  ( texinfo ) -- parsing of texinfo into SXML
;;;;
 	 Copyright ( C ) 2009 , 2010 , 2011 , 2012 , 2013 , 2014   Free Software Foundation , Inc.
     Copyright ( C ) 2004 , 2009   < wingo at pobox dot com >
     Copyright ( C ) 2001,2002 Oleg Kiselyov < oleg at pobox dot com >
;;;;
  This file is based on  's SSAX.scm .
;;;; 
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation ; either
  version 3 of the License , or ( at your option ) any later version .
;;;; 
;;;; This library is distributed in the hope that it will be useful,
;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;;;; Lesser General Public License for more details.
;;;; 
  You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
  Foundation , Inc. , 51 Franklin Street , Fifth Floor , Boston ,     USA

;;; Commentary:
;;
    processing in scheme
;; 
  This module parses texinfo into SXML .  will always be the
;; processor of choice for print output, of course. However, although
;; @code{makeinfo} works well for info, its output in other formats is
;; not very customizable, and the program is not extensible as a whole.
;; This module aims to provide an extensible framework for texinfo
  processing that integrates texinfo into the constellation of SXML
;; processing tools.
;; 
  @subheading Notes on the SXML vocabulary
;;
;; Consider the following texinfo fragment:
;; 
;;@example
;; @@deffn Primitive set-car! pair value
;; This function...
;; @@end deffn
;;@end example
;; 
;; Logically, the category (Primitive), name (set-car!), and arguments
;; (pair value) are ``attributes'' of the deffn, with the description as
  the content . However , texinfo allows for @@-commands within the
;; arguments to an environment, like @code{@@deffn}, which means that
  texinfo ` ` attributes '' are PCDATA . XML attributes , on the other hand ,
  are CDATA . For this reason , ` ` attributes '' of texinfo @@-commands are
;; called ``arguments'', and are grouped under the special element, `%'.
;;
  Because ` % ' is not a valid NCName , stexinfo is a superset of SXML . In
;; the interests of interoperability, this module provides a conversion
;; function to replace the `%' with `texinfo-arguments'.
;; 
;;; Code:

  Comparison to xml output of texinfo ( which is rather undocumented ):
   Does n't conform to  
;;  No DTD at all, in fact :-/
;;  Actually outputs valid xml, after transforming %
   Slower ( although with caching the SXML that problem can go away )
;;  Doesn't parse menus (although menus are shite)
    go in a dedicated element , FBOFW
;;  Definitions are handled a lot better
;;  Does parse comments
;;  Outputs only significant line breaks (a biggie!)
;;  Nodes are treated as anchors, rather than content organizers (a biggie)
;;    (more book-like, less info-like)

  TODO
;; Integration: help, indexing, plain text

(define-module (texinfo)
  #:use-module (sxml simple)
  #:use-module (sxml transform)
  #:use-module (sxml ssax input-parse)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-13)
  #:export (call-with-file-and-dir
            texi-command-specs
            texi-command-depth
            texi-fragment->stexi
            texi->stexi
            stexi->sxml))

;; Some utilities

(define (parser-error port message . rest)
  (apply throw 'parser-error port message rest))

(define (call-with-file-and-dir filename proc)
  "Call the one-argument procedure @var{proc} with an input port that
reads from @var{filename}. During the dynamic extent of @var{proc}'s
execution, the current directory will be @code{(dirname
@var{filename})}. This is useful for parsing documents that can include
files by relative path name."
  (let ((current-dir (getcwd)))
    (dynamic-wind
        (lambda () (chdir (dirname filename)))
        (lambda ()
          (call-with-input-file (basename filename) proc))
        (lambda () (chdir current-dir)))))

;;========================================================================
             Reflection on the XML vocabulary

(define texi-command-specs
  #;
"A list of (@var{name} @var{content-model} . @var{args})

@table @var
@item name 
The name of an @@-command, as a symbol.

@item content-model
A symbol indicating the syntactic type of the @@-command:
@table @code
@item EMPTY-COMMAND
No content, and no @code{@@end} is coming
@item EOL-ARGS
Unparsed arguments until end of line
@item EOL-TEXT
Parsed arguments until end of line
@item INLINE-ARGS
Unparsed arguments ending with @code{#\\@}}
@item INLINE-TEXT
Parsed arguments ending with @code{#\\@}}
@item INLINE-TEXT-ARGS
Parsed arguments ending with @code{#\\@}}
@item ENVIRON
The tag is an environment tag, expect @code{@@end foo}.
@item TABLE-ENVIRON
Like ENVIRON, but with special parsing rules for its arguments.
@item FRAGMENT
For @code{*fragment*}, the command used for parsing fragments of
texinfo documents.
@end table

@code{INLINE-TEXT} commands will receive their arguments within their
bodies, whereas the @code{-ARGS} commands will receive them in their
attribute list.

@code{EOF-TEXT} receives its arguments in its body.

@code{ENVIRON} commands have both: parsed arguments until the end of
line, received through their attribute list, and parsed text until the
@code{@@end}, received in their bodies.

@code{EOF-TEXT-ARGS} receives its arguments in its attribute list, as in
@code{ENVIRON}.

In addition, @code{ALIAS} can alias one command to another.  The alias
will never be seen in parsed stexinfo.

There are four @@-commands that are treated specially. @code{@@include}
is a low-level token that will not be seen by higher-level parsers, so
it has no content-model. @code{@@para} is the paragraph command, which
is only implicit in the texinfo source. @code{@@item} has special
syntax, as noted above, and @code{@@entry} is how this parser treats
@code{@@item} commands within @code{@@table}, @code{@@ftable}, and
@code{@@vtable}.

Also, indexing commands (@code{@@cindex}, etc.) are treated specially.
Their arguments are parsed, but they are needed before entering the
element so that an anchor can be inserted into the text before the index
entry.

@item args
Named arguments to the command, in the same format as the formals for a
lambda. Only present for @code{INLINE-ARGS}, @code{EOL-ARGS},
@code{INLINE-TEXT-ARGS}, @code{ENVIRON}, @code{TABLE-ENVIRON} commands.
@end table"
  '(;; Special commands
    (include            #f) ;; this is a low-level token
    (para               PARAGRAPH)
    (item               ITEM)
    (entry              ENTRY . heading)
    (noindent           EMPTY-COMMAND)
    (*fragment*         FRAGMENT)

    ;; Inline text commands
    (*braces*           INLINE-TEXT) ;; FIXME: make me irrelevant
    (bold               INLINE-TEXT)
    (sample             INLINE-TEXT)
    (samp               INLINE-TEXT)
    (code               INLINE-TEXT)
    (math               INLINE-TEXT)
    (kbd                INLINE-TEXT)
    (key                INLINE-TEXT)
    (var                INLINE-TEXT)
    (env                INLINE-TEXT)
    (file               INLINE-TEXT)
    (command            INLINE-TEXT)
    (option             INLINE-TEXT)
    (dfn                INLINE-TEXT)
    (cite               INLINE-TEXT)
    (acro               INLINE-TEXT)
    (email              INLINE-TEXT)
    (emph               INLINE-TEXT)
    (strong             INLINE-TEXT)
    (sample             INLINE-TEXT)
    (sc                 INLINE-TEXT)
    (titlefont          INLINE-TEXT)
    (asis               INLINE-TEXT)
    (b                  INLINE-TEXT)
    (i                  INLINE-TEXT)
    (r                  INLINE-TEXT)
    (sansserif          INLINE-TEXT)
    (slanted            INLINE-TEXT)
    (t                  INLINE-TEXT)

    ;; Inline args commands
    (value              INLINE-ARGS . (key))
    (ref                INLINE-ARGS . (node #:opt name section info-file manual))
    (xref               INLINE-ARGS . (node #:opt name section info-file manual))
    (pxref              INLINE-TEXT-ARGS
                        . (node #:opt name section info-file manual))
    (url                ALIAS       . uref)
    (uref               INLINE-TEXT-ARGS . (url #:opt title replacement))
    (anchor             INLINE-ARGS . (name))
    (dots               INLINE-ARGS . ())
    (result             INLINE-ARGS . ())
    (bullet             INLINE-ARGS . ())
    (copyright          INLINE-ARGS . ())
    (tie                INLINE-ARGS . ())
    (image              INLINE-ARGS . (file #:opt width height alt-text extension))

    ;; Inline parsed args commands
    (acronym            INLINE-TEXT-ARGS . (acronym #:opt meaning))

  EOL args elements
    (node               EOL-ARGS . (name #:opt next previous up))
    (c                  EOL-ARGS . all)
    (comment            EOL-ARGS . all)
    (setchapternewpage  EOL-ARGS . all)
    (sp                 EOL-ARGS . all)
    (page               EOL-ARGS . ())
    (vskip              EOL-ARGS . all)
    (syncodeindex       EOL-ARGS . all)
    (contents           EOL-ARGS . ())
    (shortcontents      EOL-ARGS . ())
    (summarycontents    EOL-ARGS . ())
    (insertcopying      EOL-ARGS . ())
    (dircategory        EOL-ARGS . (category))
    (top		EOL-ARGS . (title))
    (printindex		EOL-ARGS . (type))
    (paragraphindent    EOL-ARGS . (indent))

  EOL text commands
    (*ENVIRON-ARGS*     EOL-TEXT)
    (itemx              EOL-TEXT)
    (set                EOL-TEXT)
    (center             EOL-TEXT)
    (title              EOL-TEXT)
    (subtitle           EOL-TEXT)
    (author             EOL-TEXT)
    (chapter            EOL-TEXT)
    (section            EOL-TEXT)
    (appendix           EOL-TEXT)
    (appendixsec        EOL-TEXT)
    (unnumbered         EOL-TEXT)
    (unnumberedsec      EOL-TEXT)
    (subsection         EOL-TEXT)
    (subsubsection      EOL-TEXT)
    (appendixsubsec     EOL-TEXT)
    (appendixsubsubsec  EOL-TEXT)
    (unnumberedsubsec   EOL-TEXT)
    (unnumberedsubsubsec EOL-TEXT)
    (chapheading        EOL-TEXT)
    (majorheading       EOL-TEXT)
    (heading            EOL-TEXT)
    (subheading         EOL-TEXT)
    (subsubheading      EOL-TEXT)

    (deftpx             EOL-TEXT-ARGS . (category name . attributes))
    (defcvx             EOL-TEXT-ARGS . (category class name))
    (defivarx           EOL-TEXT-ARGS . (class name))
    (deftypeivarx       EOL-TEXT-ARGS . (class data-type name))
    (defopx             EOL-TEXT-ARGS . (category class name . arguments))
    (deftypeopx         EOL-TEXT-ARGS . (category class data-type name . arguments))
    (defmethodx         EOL-TEXT-ARGS . (class name . arguments))
    (deftypemethodx     EOL-TEXT-ARGS . (class data-type name . arguments))
    (defoptx            EOL-TEXT-ARGS . (name))
    (defvrx             EOL-TEXT-ARGS . (category name))
    (defvarx            EOL-TEXT-ARGS . (name))
    (deftypevrx         EOL-TEXT-ARGS . (category data-type name))
    (deftypevarx        EOL-TEXT-ARGS . (data-type name))
    (deffnx             EOL-TEXT-ARGS . (category name . arguments))
    (deftypefnx         EOL-TEXT-ARGS . (category data-type name . arguments))
    (defspecx           EOL-TEXT-ARGS . (name . arguments))
    (defmacx            EOL-TEXT-ARGS . (name . arguments))
    (defunx             EOL-TEXT-ARGS . (name . arguments))
    (deftypefunx        EOL-TEXT-ARGS . (data-type name . arguments))

    ;; Indexing commands
    (cindex             INDEX . entry)
    (findex             INDEX . entry)
    (vindex             INDEX . entry)
    (kindex             INDEX . entry)
    (pindex             INDEX . entry)
    (tindex             INDEX . entry)

    ;; Environment commands (those that need @end)
    (texinfo            ENVIRON . title)
    (ignore             ENVIRON . ())
    (ifinfo             ENVIRON . ())
    (iftex              ENVIRON . ())
    (ifhtml             ENVIRON . ())
    (ifxml              ENVIRON . ())
    (ifplaintext        ENVIRON . ())
    (ifnotinfo          ENVIRON . ())
    (ifnottex           ENVIRON . ())
    (ifnothtml          ENVIRON . ())
    (ifnotxml           ENVIRON . ())
    (ifnotplaintext     ENVIRON . ())
    (titlepage          ENVIRON . ())
    (menu               ENVIRON . ())
    (direntry           ENVIRON . ())
    (copying            ENVIRON . ())
    (example            ENVIRON . ())
    (smallexample       ENVIRON . ())
    (display            ENVIRON . ())
    (smalldisplay       ENVIRON . ())
    (verbatim           ENVIRON . ())
    (format             ENVIRON . ())
    (smallformat        ENVIRON . ())
    (lisp               ENVIRON . ())
    (smalllisp          ENVIRON . ())
    (cartouche          ENVIRON . ())
    (quotation          ENVIRON . ())

    (deftp              ENVIRON . (category name . attributes))
    (defcv              ENVIRON . (category class name))
    (defivar            ENVIRON . (class name))
    (deftypeivar        ENVIRON . (class data-type name))
    (defop              ENVIRON . (category class name . arguments))
    (deftypeop          ENVIRON . (category class data-type name . arguments))
    (defmethod          ENVIRON . (class name . arguments))
    (deftypemethod      ENVIRON . (class data-type name . arguments))
    (defopt             ENVIRON . (name))
    (defvr              ENVIRON . (category name))
    (defvar             ENVIRON . (name))
    (deftypevr          ENVIRON . (category data-type name))
    (deftypevar         ENVIRON . (data-type name))
    (deffn              ENVIRON . (category name . arguments))
    (deftypefn          ENVIRON . (category data-type name . arguments))
    (defspec            ENVIRON . (name . arguments))
    (defmac             ENVIRON . (name . arguments))
    (defun              ENVIRON . (name . arguments))
    (deftypefun         ENVIRON . (data-type name . arguments))

    (table              TABLE-ENVIRON . (formatter))
    (itemize            TABLE-ENVIRON . (formatter))
    (enumerate          TABLE-ENVIRON . (start))
    (ftable             TABLE-ENVIRON . (formatter))
    (vtable             TABLE-ENVIRON . (formatter))))

(define command-depths
  '((chapter . 1) (section . 2) (subsection . 3) (subsubsection . 4)
    (top . 0) (unnumbered . 1) (unnumberedsec . 2)
    (unnumberedsubsec . 3) (unnumberedsubsubsec . 4)
    (appendix . 1) (appendixsec . 2) (appendixsection . 2)
    (appendixsubsec . 3) (appendixsubsubsec . 4)))
(define (texi-command-depth command max-depth)
  "Given the texinfo command @var{command}, return its nesting level, or
@code{#f} if it nests too deep for @var{max-depth}.

Examples:
@example
 (texi-command-depth 'chapter 4)        @result{} 1
 (texi-command-depth 'top 4)            @result{} 0
 (texi-command-depth 'subsection 4)     @result{} 3
 (texi-command-depth 'appendixsubsec 4) @result{} 3
 (texi-command-depth 'subsection 2)     @result{} #f
@end example"
  (let ((depth (and=> (assq command command-depths) cdr)))
    (and depth (<= depth max-depth) depth)))

;; The % is for arguments
(define (space-significant? command)
  (memq command
        '(example smallexample verbatim lisp smalllisp menu %)))

  Like a DTD for texinfo
(define (command-spec command)
  (let ((spec (assq command texi-command-specs)))
    (cond
     ((not spec)
      (parser-error #f "Unknown command" command))
     ((eq? (cadr spec) 'ALIAS)
      (command-spec (cddr spec)))
     (else
      spec))))

(define (inline-content? content)
  (case content
    ((INLINE-TEXT INLINE-ARGS INLINE-TEXT-ARGS) #t)
    (else #f)))


;;========================================================================
;;		Lower-level parsers and scanners
;;
;; They deal with primitive lexical units (Names, whitespaces, tags) and
;; with pieces of more generic productions. Most of these parsers must
;; be called in appropriate context. For example, complete-start-command
;; must be called only when the @-command start has been detected and
;; its name token has been read.

;; Test if a string is made of only whitespace
;; An empty string is considered made of whitespace as well
(define (string-whitespace? str)
  (or (string-null? str)
      (string-every char-whitespace? str)))

  Like read - text - line , but allows EOF .
(define read-eof-breaks '(*eof* #\return #\newline))
(define (read-eof-line port)
  (if (eof-object? (peek-char port))
      (peek-char port)
      (let* ((line (next-token '() read-eof-breaks
                               "reading a line" port))
  must be either  or \r or EOF
        (if (and (eq? c #\return) (eq? (peek-char port) #\newline))
  skip  that follows \r
        line)))

(define (skip-whitespace port)
  (skip-while '(#\space #\tab #\return #\newline) port))

(define (skip-horizontal-whitespace port)
  (skip-while '(#\space #\tab) port))

;; command ::= Letter+

;; procedure:   read-command PORT
;;
;; Read a command starting from the current position in the PORT and
;; return it as a symbol.
(define (read-command port)
  (let ((first-char (peek-char port)))
    (or (char-alphabetic? first-char)
        (parser-error port "Nonalphabetic @-command char: '" first-char "'")))
  (string->symbol
    (next-token-of
      (lambda (c)
        (cond
          ((eof-object? c) #f)
          ((char-alphabetic? c) c)
          (else #f)))
      port)))

  A token is a primitive lexical unit . It is a record with two fields ,
;; token-head and token-kind.
;;
;; Token types:
;;      END     The end of a texinfo command. If the command is ended by },
;;              token-head will be #f. Otherwise if the command is ended by
;;              @end COMMAND, token-head will be COMMAND. As a special case,
;;              @bye is the end of a special @texinfo command.
       START    The start of a texinfo command . The token - head will be a
;;              symbol of the @-command name.
;;      INCLUDE An @include directive. The token-head will be empty -- the
;;              caller is responsible for reading the include file name.
       ITEM      commands have an irregular syntax . They end at the
;;              next @item, or at the end of the environment. For that
;;              read-command-token treats them specially.

(define (make-token kind head) (cons kind head))
(define token? pair?)
(define token-kind car)
(define token-head cdr)

;; procedure:	read-command-token PORT
;;
;; This procedure starts parsing of a command token. The current
  position in the stream must be # \@. This procedure scans enough of
;; the input stream to figure out what kind of a command token it is
;; seeing. The procedure returns a token structure describing the token.

(define (read-command-token port)
  (assert-curr-char '(#\@) "start of the command" port)
  (let ((peeked (peek-char port)))
    (cond
     ((memq peeked '(#\! #\: #\. #\? #\@ #\\ #\{ #\}))
  @-commands that escape characters
      (make-token 'STRING (string (read-char port))))
     (else
      (let ((name (read-command port)))
        (case name
          ((end)
           ;; got an ending tag
           (let ((command (string-trim-both
                           (read-eof-line port))))
             (or (and (not (string-null? command))
                      (string-every char-alphabetic? command))
                 (parser-error port "malformed @end" command))
             (make-token 'END (string->symbol command))))
          ((bye)
           ;; the end of the top
           (make-token 'END 'texinfo))
          ((item)
           (make-token 'ITEM 'item))
          ((include)
           (make-token 'INCLUDE #f))
          (else
           (make-token 'START name))))))))

;; procedure+: 	read-verbatim-body PORT STR-HANDLER SEED
;;
;; This procedure must be called after we have read a string
;; "@verbatim\n" that begins a verbatim section. The current position
  must be the first position of the verbatim body . This function reads
;; _lines_ of the verbatim body and passes them to a STR-HANDLER, a
;; character data consumer.
;;
;; The str-handler is a STR-HANDLER, a procedure STRING1 STRING2 SEED.
  The first STRING1 argument to STR - HANDLER never contains a newline .
  The second STRING2 argument often will . On the first invocation of the
;; STR-HANDLER, the seed is the one passed to read-verbatim-body
  as the third argument . The result of this first invocation will be
  passed as the seed argument to the second invocation of the line
;; consumer, and so on. The result of the last invocation of the
;; STR-HANDLER is returned by the read-verbatim-body. Note a
;; similarity to the fundamental 'fold' iterator.
;;
;; Within a verbatim section all characters are taken at their face
;; value. It ends with "\n@end verbatim(\r)?\n".

;; Must be called right after the newline after @verbatim.
(define (read-verbatim-body port str-handler seed)
  (let loop ((seed seed))
    (let ((fragment (next-token '() '(#\newline)
                                "reading verbatim" port)))
      ;; We're reading the char after the 'fragment', which is
      ;; #\newline.
      (read-char port)
      (if (string=? fragment "@end verbatim")
          seed
          (loop (str-handler fragment "\n" seed))))))

;; procedure+:	read-arguments PORT
;;
  This procedure reads and parses a production ArgumentList .
  ArgumentList : : = S * Argument ( S * , S * Argument ) * S *
;; Argument ::= ([^@{},])*
;;
  Arguments are the things in braces , i.e @ref{my node } has one
;; argument, "my node". Most commands taking braces actually don't have
;; arguments, they process text. For example, in
;; @emph{@strong{emphasized}}, the emph takes text, because the parse
;; continues into the braces.
;;
;; Any whitespace within Argument is replaced with a single space.
  Whitespace around an Argument is trimmed .
;;
;; The procedure returns a list of arguments. Afterwards the current
;; character will be after the final #\}.

(define (read-arguments port stop-char)
  (define (split str)
    (read-char port) ;; eat the delimiter
    (let ((ret (map (lambda (x) (if (string-null? x) #f x))
                    (map string-trim-both (string-split str #\,)))))
      (if (and (pair? ret) (eq? (car ret) #f) (null? (cdr ret)))
          '()
          ret)))
  (split (next-token '() (list stop-char)
                     "arguments of @-command" port)))

;; procedure+:	complete-start-command COMMAND PORT
;;
;; This procedure is to complete parsing of an @-command. The procedure
;; must be called after the command token has been read. COMMAND is a
  TAG - NAME .
;;
;; This procedure returns several values:
;;  COMMAND: a symbol.
;;  ARGUMENTS: command's arguments, as an alist.
;;  CONTENT-MODEL: the content model of the command.
;;
;; On exit, the current position in PORT will depend on the CONTENT-MODEL.
;;
  Content model      Port position
;; =============     =============
  INLINE - TEXT        One character after the # \ { .
  INLINE - TEXT - ARGS   One character after the # \ { .
  INLINE - ARGS        The first character after the # \ } .
  EOL - TEXT           The first non - whitespace character after the command .
  ENVIRON , TABLE - ENVIRON , EOL - ARGS , EOL - TEXT
                    The first character on the next line .
  PARAGRAPH , ITEM , EMPTY - COMMAND
                    The first character after the command .

(define (arguments->attlist port args arg-names)
  (let loop ((in args) (names arg-names) (opt? #f) (out '()))
    (cond
     ((symbol? names) ;; a rest arg
      (reverse (if (null? in) out (acons names in out))))
     ((and (not (null? names)) (eq? (car names) #:opt))
      (loop in (cdr names) #t out))
     ((null? in)
      (if (or (null? names) opt?)
          (reverse out)
          (parser-error port "@-command expected more arguments:" 
                        args arg-names names)))
     ((null? names)
      (parser-error port "@-command didn't expect more arguments:" in))
     ((not (car in))
      (or (and opt? (loop (cdr in) (cdr names) opt? out))
          (parser-error "@-command missing required argument"
                        (car names))))
     (else
      (loop (cdr in) (cdr names) opt?
            (acons (car names)
                   (if (list? (car in)) (car in) (list (car in)))
                   out))))))

(define (parse-table-args command port)
  (let* ((line (string-trim-both (read-text-line port)))
         (length (string-length line)))
    (define (get-formatter)
      (or (and (not (zero? length))
               (eq? (string-ref line 0) #\@)
               (let ((f (string->symbol (substring line 1))))
                 (or (inline-content? (cadr (command-spec f)))
                     (parser-error
                      port "@item formatter must be INLINE" f))
                 f))
          (parser-error port "Invalid @item formatter" line)))
    (case command
      ((enumerate)
       (if (zero? length)
           '()
           `((start
              ,(if (or (and (eq? length 1)
                            (char-alphabetic? (string-ref line 0)))
                       (string-every char-numeric? line))
                   line
                   (parser-error
                    port "Invalid enumerate start" line))))))
      ((itemize)
       `((bullet
          ,(or (and (eq? length 1) line)
               (and (string-null? line) '(bullet))
               (list (get-formatter))))))
      (else ;; tables of various varieties
       `((formatter (,(get-formatter))))))))

(define (complete-start-command command port)
  (define (get-arguments type arg-names stop-char)
    (arguments->attlist port (read-arguments port stop-char) arg-names))

  (let* ((spec (command-spec command))
         (command (car spec))
         (type (cadr spec))
         (arg-names (cddr spec)))
    (case type
      ((INLINE-TEXT)
       (assert-curr-char '(#\{) "Inline element lacks {" port)
       (values command '() type))
      ((INLINE-ARGS)
       (assert-curr-char '(#\{) "Inline element lacks {" port)
       (values command (get-arguments type arg-names #\}) type))
      ((INLINE-TEXT-ARGS)
       (assert-curr-char '(#\{) "Inline element lacks {" port)
       (values command '() type))
      ((EOL-ARGS)
       (values command (get-arguments type arg-names #\newline) type))
      ((ENVIRON ENTRY INDEX)
       (skip-horizontal-whitespace port)
       (values command (parse-environment-args command port) type))
      ((TABLE-ENVIRON)
       (skip-horizontal-whitespace port)
       (values command (parse-table-args command port) type))
      ((EOL-TEXT)
       (skip-horizontal-whitespace port)
       (values command '() type))
      ((EOL-TEXT-ARGS)
       (skip-horizontal-whitespace port)
       (values command (parse-eol-text-args command port) type))
      ((PARAGRAPH EMPTY-COMMAND ITEM FRAGMENT)
       (values command '() type))
      (else ;; INCLUDE shouldn't get here
       (parser-error port "can't happen")))))

;;-----------------------------------------------------------------------------
;;			Higher-level parsers and scanners
;;
  They parse productions corresponding entire @-commands .

  Only reads @settitle , leaves it to the command parser to finish
;; reading the title.
(define (take-until-settitle port)
  (or (find-string-from-port? "\n@settitle " port)
      (parser-error port "No \\n@settitle  found"))
  (skip-horizontal-whitespace port)
  (and (eq? (peek-char port) #\newline)
       (parser-error port "You have a @settitle, but no title")))

;; procedure+:	read-char-data PORT EXPECT-EOF? STR-HANDLER SEED
;;
  This procedure is to read the CharData of a texinfo document .
;;
  text : : = ( CharData | Command ) *
;;
  The procedure reads CharData and stops at @-commands ( or
;; environments). It also stops at an open or close brace.
;;
;; port
;;	a PORT to read
;; expect-eof?
	 a boolean indicating if EOF is normal , i.e. , the character
	 data may be terminated by the EOF . EOF is normal
;;	while processing the main document.
;; preserve-ws?
;;	a boolean indicating if we are within a whitespace-preserving
;;      environment. If #t, suppress paragraph detection.
;; str-handler
;;	a STR-HANDLER, see read-verbatim-body
;; seed
	 an argument passed to the first invocation of STR - HANDLER .
;;
  The procedure returns two results : SEED and TOKEN . The SEED is the
;; result of the last invocation of STR-HANDLER, or the original seed if
;; STR-HANDLER was never called.
;;
  TOKEN can be either an eof - object ( this can happen only if expect - eof ?
  was # t ) , or a texinfo token denoting the start or end of a tag .

;; read-char-data port expect-eof? preserve-ws? str-handler seed
(define read-char-data
  (let* ((end-chars-eof '(*eof* #\{ #\} #\@ #\newline)))
    (define (handle str-handler str1 str2 seed)
      (if (and (string-null? str1) (string-null? str2))
          seed
          (str-handler str1 str2 seed)))

    (lambda (port expect-eof? preserve-ws? str-handler seed)
      (let ((end-chars ((if expect-eof? identity cdr) end-chars-eof)))
        (let loop ((seed seed))
          (let* ((fragment (next-token '() end-chars "reading char data" port))
                 (term-char (peek-char port))) ; one of end-chars
            (cond
             ((eof-object? term-char) ; only if expect-eof?
              (values (handle str-handler fragment "" seed) term-char))
             ((memq term-char '(#\@ #\{ #\}))
              (values (handle str-handler fragment "" seed)
                      (case term-char
                        ((#\@) (read-command-token port))
                        ((#\{) (make-token 'START '*braces*))
                        ((#\}) (read-char port) (make-token 'END #f)))))
             ((eq? term-char #\newline)
              ;; Always significant, unless directly before an end token.
              (let ((c (peek-next-char port)))
                (cond
                 ((eof-object? c)
                  (or expect-eof?
                      (parser-error port "EOF while reading char data"))
                  (values (handle str-handler fragment "" seed) c))
                 ((eq? c #\@)
                  (let* ((token (read-command-token port))
                         (end? (eq? (token-kind token) 'END)))
                    (values
                     (handle str-handler fragment
                             (if end? "" (if preserve-ws? "\n" " "))
                             seed)
                     token)))
                 ((and (not preserve-ws?) (eq? c #\newline))
  paragraph - separator : : = # \newline # \newline+
                  (skip-while '(#\newline) port)
                  (skip-horizontal-whitespace port)
                  (values (handle str-handler fragment "" seed)
                          (make-token 'PARA 'para)))
                 (else
                  (loop (handle str-handler fragment
                                (if preserve-ws? "\n" " ") seed)))))))))))))

; procedure+:	assert-token TOKEN KIND NAME
  Make sure that TOKEN is of anticipated KIND and has anticipated NAME
(define (assert-token token kind name)
  (or (and (token? token)
           (eq? kind (token-kind token))
           (equal? name (token-head token)))
      (parser-error #f "Expecting @end for " name ", got " token)))

;;========================================================================
		 Highest - level parsers : Texinfo to SXML

;; These parsers are a set of syntactic forms to instantiate a SSAX
;; parser. The user tells what to do with the parsed character and
;; element data. These latter handlers determine if the parsing follows a
  SAX or a DOM model .

  syntax : make - command - parser fdown    

  Create a parser to parse and process one element , including its
;; character content or children elements. The parser is typically
;; applied to the root element of a document.

;; fdown
;;	procedure COMMAND ARGUMENTS EXPECTED-CONTENT SEED
;;
;;	This procedure is to generate the seed to be passed to handlers
;;	that process the content of the element. This is the function
;;	identified as 'fdown' in the denotational semantics of the XML
	 parser given in the title comments to (   ) .
;;
;; fup
;;	procedure COMMAND ARGUMENTS PARENT-SEED SEED
;;
;;	This procedure is called when parsing of COMMAND is finished.
;;	The SEED is the result from the last content parser (or from
	 fdown if the element has the empty content ) . PARENT - SEED is the
;;	same seed as was passed to fdown. The procedure is to generate a
;;	seed that will be the result of the element parser. This is the
;;	function identified as 'fup' in the denotational semantics of
	 the XML parser given in the title comments to (   ) .
;;
;; str-handler
;;	A STR-HANDLER, see read-verbatim-body
;;

;; The generated parser is a
;;	procedure COMMAND PORT SEED
;;
;; The procedure must be called *after* the command token has been read.

(define (read-include-file-name port)
  (let ((x (string-trim-both (read-eof-line port))))
    (if (string-null? x)
        (error "no file listed")
  fixme : should expand @value { } references

(define (sxml->node-name sxml)
  "Turn some sxml string into a valid node name."
  (let loop ((in (string->list (sxml->string sxml))) (out '()))
    (if (null? in)
        (apply string (reverse out))
        (if (memq (car in) '(#\{ #\} #\@ #\,))
            (loop (cdr in) out)
            (loop (cdr in) (cons (car in) out))))))

(define (index command arguments fdown fup parent-seed)
  (case command
    ((deftp defcv defivar deftypeivar defop deftypeop defmethod
      deftypemethod defopt defvr defvar deftypevr deftypevar deffn
      deftypefn defspec defmac defun deftypefun)
     (let ((args `((name ,(string-append (symbol->string command) "-"
                                         (cadr (assq 'name arguments)))))))
       (fup 'anchor args parent-seed
            (fdown 'anchor args 'INLINE-ARGS '()))))
    ((cindex findex vindex kindex pindex tindex)
     (let ((args `((name ,(string-append (symbol->string command) "-"
                                         (sxml->node-name
                                          (assq 'entry arguments)))))))
       (fup 'anchor args parent-seed
            (fdown 'anchor args 'INLINE-ARGS '()))))
    (else parent-seed)))

(define (make-command-parser fdown fup str-handler)
  (lambda (command port seed)
    (let visit ((command command) (port port) (sig-ws? #f) (parent-seed seed))
      (let*-values (((command arguments expected-content)
                     (complete-start-command command port)))
        (let* ((parent-seed (index command arguments fdown fup parent-seed))
               (seed (fdown command arguments expected-content parent-seed))
               (eof-closes? (or (memq command '(texinfo para *fragment*))
                                (eq? expected-content 'EOL-TEXT)))
               (sig-ws? (or sig-ws? (space-significant? command)))
               (up (lambda (s) (fup command arguments parent-seed s)))
               (new-para (lambda (s) (fdown 'para '() 'PARAGRAPH s)))
               (make-end-para (lambda (p) (lambda (s) (fup 'para '() p s)))))
          
          (define (port-for-content)
            (if (eq? expected-content 'EOL-TEXT)
                (call-with-input-string (read-text-line port) identity)
                port))

          (cond
           ((memq expected-content '(EMPTY-COMMAND INLINE-ARGS EOL-ARGS INDEX
                                     EOL-TEXT-ARGS))
            ;; empty or finished by complete-start-command
            (up seed))
           ((eq? command 'verbatim)
            (up (read-verbatim-body port str-handler seed)))
           (else
            (let loop ((port (port-for-content))
                       (expect-eof? eof-closes?)
                       (end-para identity)
                       (need-break? (and (not sig-ws?)
                                         (memq expected-content
                                               '(ENVIRON TABLE-ENVIRON
                                                 ENTRY ITEM FRAGMENT))))
                       (seed seed))
              (cond
               ((and need-break? (or sig-ws? (skip-whitespace port))
                     (not (memq (peek-char port) '(#\@ #\})))
                     (not (eof-object? (peek-char port))))
                ;; Even if we have an @, it might be inline -- check
                ;; that later
                (let ((seed (end-para seed)))
                  (loop port expect-eof? (make-end-para seed) #f
                        (new-para seed))))
               (else
                (let*-values (((seed token)
                               (read-char-data
                                port expect-eof? sig-ws? str-handler seed)))
                  (cond
                   ((eof-object? token)
                    (case expect-eof? 
                      ((include #f) (end-para seed))
                      (else (up (end-para seed)))))
                   (else
                    (case (token-kind token)
                      ((STRING)
                       ;; this is only @-commands that escape
                       ;; characters: @}, @@, @{ -- new para if need-break
                       (let ((seed ((if need-break? end-para identity) seed)))
                         (loop port expect-eof?
                               (if need-break? (make-end-para seed) end-para) #f
                               (str-handler (token-head token) ""
                                            ((if need-break? new-para identity)
                                             seed)))))
                      ((END)
                       ;; The end will only have a name if it's for an
                       ;; environment
                       (cond
                        ((memq command '(item entry))
                         (let ((spec (command-spec (token-head token))))
                           (or (eq? (cadr spec) 'TABLE-ENVIRON)
                               (parser-error
                                port "@item not ended by @end table/enumerate/itemize"
                                token))))
                        ((eq? expected-content 'ENVIRON)
                         (assert-token token 'END command)))
                       (up (end-para seed)))
                      ((ITEM)
                       (cond
                        ((memq command '(enumerate itemize))
                         (up (visit 'item port sig-ws? (end-para seed))))
                        ((eq? expected-content 'TABLE-ENVIRON)
                         (up (visit 'entry port sig-ws? (end-para seed))))
                        ((memq command '(item entry))
                         (visit command port sig-ws? (up (end-para seed))))
                        (else
                         (parser-error
                          port "@item must be within a table environment"
                          command))))
                      ((PARA)
                       ;; examine valid paragraphs?
                       (loop port expect-eof? end-para (not sig-ws?) seed))
                      ((INCLUDE)
                       ;; Recurse for include files
                       (let ((seed (call-with-file-and-dir
                                    (read-include-file-name port)
                                    (lambda (port)
                                      (loop port 'include end-para
                                            need-break? seed)))))
                         (loop port expect-eof? end-para need-break? seed)))
                      ((START)          ; Start of an @-command
                       (let* ((head (token-head token))
                              (spec (command-spec head))
                              (head (car spec))
                              (type (cadr spec))
                              (inline? (inline-content? type))
                              (seed ((if (and inline? (not need-break?))
                                         identity end-para) seed))
                              (end-para (if inline?
                                            (if need-break? (make-end-para seed)
                                                end-para)
                                            identity))
                              (new-para (if (and inline? need-break?)
                                            new-para identity)))
                         (loop port expect-eof? end-para (not inline?)
                               (visit head port sig-ws? (new-para seed)))))
                      (else
                       (parser-error port "Unknown token type" token))))))))))))))))

;; procedure: reverse-collect-str-drop-ws fragments
;;
;; Given the list of fragments (some of which are text strings), reverse
;; the list and concatenate adjacent text strings. We also drop
;; "unsignificant" whitespace, that is, whitespace in front, behind and
;; between elements. The whitespace that is included in character data
;; is not affected.
(define (reverse-collect-str-drop-ws fragments)
  (cond 
   ((null? fragments)                   ; a shortcut
    '())
   ((and (string? (car fragments))	; another shortcut
         (null? (cdr fragments))	; remove single ws-only string
         (string-whitespace? (car fragments)))
    '())
   (else
    (let loop ((fragments fragments) (result '()) (strs '())
               (all-whitespace? #t))
      (cond
       ((null? fragments)
        (if all-whitespace?
            result                      ; remove leading ws
            (cons (apply string-append strs) result)))
       ((string? (car fragments))
        (loop (cdr fragments) result (cons (car fragments) strs)
              (and all-whitespace?
                   (string-whitespace? (car fragments)))))
       (else
        (loop (cdr fragments)
              (cons
               (car fragments)
               (cond
                ((null? strs) result)
                (all-whitespace?
                 (if (null? result)
                     result             ; remove trailing whitespace
                     (cons " " result))); replace interstitial ws with
  one space
                (else
                 (cons (apply string-append strs) result))))
              '() #t)))))))

(define (parse-inline-text-args port spec text)
  (let lp ((in text) (cur '()) (out '()))
    (cond
     ((null? in)
      (if (and (pair? cur)
               (string? (car cur))
               (string-whitespace? (car cur)))
          (lp in (cdr cur) out)
          (let ((args (reverse (if (null? cur)
                                   out
                                   (cons (reverse cur) out)))))
            (arguments->attlist port args (cddr spec)))))
     ((pair? (car in))
      (lp (cdr in) (cons (car in) cur) out))
     ((string-index (car in) #\,)
      (let* ((parts (string-split (car in) #\,))
             (head (string-trim-right (car parts)))
             (rev-tail (reverse (cdr parts)))
             (last (string-trim (car rev-tail))))
        (lp (cdr in)
            (if (string-null? last) cur (cons last cur))
            (append (cdr rev-tail)
                    (cons (reverse (if (string-null? head) cur (cons head cur)))
                          out)))))
     (else
      (lp (cdr in)
          (cons (if (null? cur) (string-trim (car in)) (car in)) cur)
          out)))))

(define (make-dom-parser)
  (make-command-parser
   (lambda (command args content seed)      ; fdown
     '())
   (lambda (command args parent-seed seed)  ; fup
     (let* ((seed (reverse-collect-str-drop-ws seed))
            (spec (command-spec command))
            (command (car spec)))
       (if (eq? (cadr spec) 'INLINE-TEXT-ARGS)
           (cons (list command (cons '% (parse-inline-text-args #f spec seed)))
                 parent-seed)
           (acons command
                  (if (null? args) seed (acons '% args seed))
                  parent-seed))))
   (lambda (string1 string2 seed)           ; str-handler
     (if (string-null? string2)
         (cons string1 seed)
         (cons* string2 string1 seed)))))

(define parse-environment-args
  (let ((parser (make-dom-parser)))
    ;; duplicate arguments->attlist to avoid unnecessary splitting
    (lambda (command port)
      (let* ((args (cdar (parser '*ENVIRON-ARGS* port '())))
             (spec (command-spec command))
             (command (car spec))
             (arg-names (cddr spec)))
        (cond
         ((not arg-names)
          (if (null? args) '()
              (parser-error port "@-command doesn't take args" command)))
         ((eq? arg-names #t)
          (list (cons 'arguments args)))
         (else
          (let loop ((args args) (arg-names arg-names) (out '()))
            (cond
             ((null? arg-names)
              (if (null? args) (reverse! out)
                  (parser-error port "@-command didn't expect more args"
                                command args)))
             ((symbol? arg-names)
              (reverse! (acons arg-names args out)))
             ((null? args)
              (parser-error port "@-command expects more args"
                            command arg-names))
             ((and (string? (car args)) (string-index (car args) #\space))
              => (lambda (i)
                   (let ((rest (substring/shared (car args) (1+ i))))
                     (if (zero? i)
                         (loop (cons rest (cdr args)) arg-names out)
                         (loop (cons rest (cdr args)) (cdr arg-names)
                               (cons (list (car arg-names)
                                           (substring (car args) 0 i))
                                     out))))))
             (else
              (loop (cdr args) (cdr arg-names)
                    (if (and (pair? (car args)) (eq? (caar args) '*braces*))
                        (acons (car arg-names) (cdar args) out)
                        (cons (list (car arg-names) (car args)) out))))))))))))
   
(define (parse-eol-text-args command port)
  ;; perhaps parse-environment-args should be named more
  ;; generically.
  (parse-environment-args command port))

;; procedure: texi-fragment->stexi STRING
;;
  A DOM parser for a texinfo fragment STRING .
;;
  The procedure returns an SXML tree headed by the special tag ,
;; *fragment*.

(define (texi-fragment->stexi string-or-port)
  "Parse the texinfo commands in @var{string-or-port}, and return the
resultant stexi tree. The head of the tree will be the special command,
@code{*fragment*}."
  (define (parse port)
    (postprocess (car ((make-dom-parser) '*fragment* port '()))))
  (if (input-port? string-or-port)
      (parse string-or-port)
      (call-with-input-string string-or-port parse)))

;; procedure: texi->stexi PORT
;;
  This is an instance of a SSAX parser above that returns an SXML
;; representation of the texinfo document ready to be read at PORT.
;;
  The procedure returns an SXML tree . The port points to the
;; first character after the @bye, or to the end of the file.

(define (texi->stexi port)
  "Read a full texinfo document from @var{port} and return the parsed
stexi tree. The parsing will start at the @code{@@settitle} and end at
@code{@@bye} or EOF."
  (let ((parser (make-dom-parser)))
    (take-until-settitle port)
    (postprocess (car (parser 'texinfo port '())))))

(define (car-eq? x y) (and (pair? x) (eq? (car x) y)))
(define (make-contents tree)
  (define (lp in out depth)
    (cond
     ((null? in) (values in (cons 'enumerate (reverse! out))))
     ((and (pair? (cdr in)) (texi-command-depth (caadr in) 4))
      => (lambda (new-depth)
           (let ((node-name (and (car-eq? (car in) 'node)
                                 (cadr (assq 'name (cdadar in))))))
             (cond
              ((< new-depth depth)
               (values in (cons 'enumerate (reverse! out))))
              ((> new-depth depth)
               (let ((out-cdr (if (null? out) '() (cdr out)))
                     (out-car (if (null? out) (list 'item) (car out))))
                 (let*-values (((new-in new-out) (lp in '() (1+ depth))))
                   (lp new-in
                       (cons (append out-car (list new-out)) out-cdr)
                       depth))))
              (else ;; same depth
               (lp (cddr in)
                   (cons
                    `(item (para
                            ,@(if node-name
                                  `((ref (% (node ,node-name))))
                                  (cdadr in))))
                    out)
                   depth))))))
     (else (lp (cdr in) out depth))))
  (let*-values (((_ contents) (lp tree '() 1)))
    `((chapheading "Table of Contents") ,contents)))

(define (trim-whitespace str trim-left? trim-right?)
  (let* ((left-space? (and (not trim-left?)
                           (string-prefix? " " str)))
         (right-space? (and (not trim-right?)
                            (string-suffix? " " str)))
         (tail (append! (string-tokenize str)
                        (if right-space? '("") '()))))
    (string-join (if left-space? (cons "" tail) tail))))

(define (postprocess tree)
  (define (loop in out state first? sig-ws?)
    (cond
     ((null? in)
      (values (reverse! out) state))
     ((string? (car in))
      (loop (cdr in)
            (cons (if sig-ws? (car in)
                      (trim-whitespace (car in) first? (null? (cdr in))))
                  out)
            state #f sig-ws?))
     ((pair? (car in))
      (case (caar in)
        ((set)
         (if (null? (cdar in)) (error "@set missing arguments" in))
         (if (string? (cadar in))
             (let ((i (string-index (cadar in) #\space)))
               (if i 
                   (loop (cdr in) out
                         (acons (substring (cadar in) 0 i)
                                (cons (substring (cadar in) (1+ i)) (cddar in))
                                state)
                         #f sig-ws?)
                   (loop (cdr in) out (acons (cadar in) (cddar in) state)
                         #f sig-ws?)))
             (error "expected a constant to define for @set" in)))
        ((value)
         (loop (fold-right cons (cdr in)
                           (or (and=>
                                (assoc (cadr (assq 'key (cdadar in))) state) cdr)
                               (error "unknown value" (cdadar in) state)))
               out
               state #f sig-ws?))
        ((copying)
         (loop (cdr in) out (cons (car in) state) #f sig-ws?))
        ((insertcopying)
         (loop (fold-right cons (cdr in)
                           (or (cdr (assoc 'copying state))
                               (error "copying isn't set yet")))
               out
               state #f sig-ws?))
        ((contents)
         (loop (cdr in) (fold cons out (make-contents tree)) state #f sig-ws?))
        (else
         (let*-values (((kid-out state)
                        (loop (car in) '() state #t
                              (or sig-ws? (space-significant? (caar in))))))
           (loop (cdr in) (cons kid-out out) state #f sig-ws?)))))
     (else ; a symbol
      (loop (cdr in) (cons (car in) out) state #t sig-ws?))))

  (call-with-values
      (lambda () (loop tree '() '() #t #f))
    (lambda (out state) out)))

;; Replace % with texinfo-arguments.
(define (stexi->sxml tree)
  "Transform the stexi tree @var{tree} into sxml. This involves
replacing the @code{%} element that keeps the texinfo arguments with an
element for each argument.

FIXME: right now it just changes % to @code{texinfo-arguments} -- that
doesn't hang with the idea of making a dtd at some point"
  (pre-post-order
   tree
   `((% . ,(lambda (x . t) (cons 'texinfo-arguments t)))
     (*text* . ,(lambda (x t) t))
     (*default* . ,(lambda (x . t) (cons x t))))))

  arch - tag : 73890afa-597c-4264 - ae70 - 46fe7756ffb5
;;; texinfo.scm ends here



 
 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 either
 
 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.
 
 License along with this library; if not, write to the Free Software
 Commentary:

 
 processor of choice for print output, of course. However, although
 @code{makeinfo} works well for info, its output in other formats is
 not very customizable, and the program is not extensible as a whole.
 This module aims to provide an extensible framework for texinfo
 processing tools.
 

 Consider the following texinfo fragment:
 
@example
 @@deffn Primitive set-car! pair value
 This function...
 @@end deffn
@end example
 
 Logically, the category (Primitive), name (set-car!), and arguments
 (pair value) are ``attributes'' of the deffn, with the description as
 arguments to an environment, like @code{@@deffn}, which means that
 called ``arguments'', and are grouped under the special element, `%'.

 the interests of interoperability, this module provides a conversion
 function to replace the `%' with `texinfo-arguments'.
 
 Code:
  No DTD at all, in fact :-/
  Actually outputs valid xml, after transforming %
  Doesn't parse menus (although menus are shite)
  Definitions are handled a lot better
  Does parse comments
  Outputs only significant line breaks (a biggie!)
  Nodes are treated as anchors, rather than content organizers (a biggie)
    (more book-like, less info-like)
 Integration: help, indexing, plain text
 Some utilities
========================================================================

 Special commands
 this is a low-level token
 Inline text commands
 FIXME: make me irrelevant
 Inline args commands
 Inline parsed args commands
 Indexing commands
 Environment commands (those that need @end)
 The % is for arguments
========================================================================
		Lower-level parsers and scanners

 They deal with primitive lexical units (Names, whitespaces, tags) and
 with pieces of more generic productions. Most of these parsers must
 be called in appropriate context. For example, complete-start-command
 must be called only when the @-command start has been detected and
 its name token has been read.
 Test if a string is made of only whitespace
 An empty string is considered made of whitespace as well
 command ::= Letter+
 procedure:   read-command PORT

 Read a command starting from the current position in the PORT and
 return it as a symbol.
 token-head and token-kind.

 Token types:
      END     The end of a texinfo command. If the command is ended by },
              token-head will be #f. Otherwise if the command is ended by
              @end COMMAND, token-head will be COMMAND. As a special case,
              @bye is the end of a special @texinfo command.
              symbol of the @-command name.
      INCLUDE An @include directive. The token-head will be empty -- the
              caller is responsible for reading the include file name.
              next @item, or at the end of the environment. For that
              read-command-token treats them specially.
 procedure:	read-command-token PORT

 This procedure starts parsing of a command token. The current
 the input stream to figure out what kind of a command token it is
 seeing. The procedure returns a token structure describing the token.
 got an ending tag
 the end of the top
 procedure+: 	read-verbatim-body PORT STR-HANDLER SEED

 This procedure must be called after we have read a string
 "@verbatim\n" that begins a verbatim section. The current position
 _lines_ of the verbatim body and passes them to a STR-HANDLER, a
 character data consumer.

 The str-handler is a STR-HANDLER, a procedure STRING1 STRING2 SEED.
 STR-HANDLER, the seed is the one passed to read-verbatim-body
 consumer, and so on. The result of the last invocation of the
 STR-HANDLER is returned by the read-verbatim-body. Note a
 similarity to the fundamental 'fold' iterator.

 Within a verbatim section all characters are taken at their face
 value. It ends with "\n@end verbatim(\r)?\n".
 Must be called right after the newline after @verbatim.
 We're reading the char after the 'fragment', which is
 #\newline.
 procedure+:	read-arguments PORT

 Argument ::= ([^@{},])*

 argument, "my node". Most commands taking braces actually don't have
 arguments, they process text. For example, in
 @emph{@strong{emphasized}}, the emph takes text, because the parse
 continues into the braces.

 Any whitespace within Argument is replaced with a single space.

 The procedure returns a list of arguments. Afterwards the current
 character will be after the final #\}.
 eat the delimiter
 procedure+:	complete-start-command COMMAND PORT

 This procedure is to complete parsing of an @-command. The procedure
 must be called after the command token has been read. COMMAND is a

 This procedure returns several values:
  COMMAND: a symbol.
  ARGUMENTS: command's arguments, as an alist.
  CONTENT-MODEL: the content model of the command.

 On exit, the current position in PORT will depend on the CONTENT-MODEL.

 =============     =============
 a rest arg
 tables of various varieties
 INCLUDE shouldn't get here
-----------------------------------------------------------------------------
			Higher-level parsers and scanners

 reading the title.
 procedure+:	read-char-data PORT EXPECT-EOF? STR-HANDLER SEED



 environments). It also stops at an open or close brace.

 port
	a PORT to read
 expect-eof?
	while processing the main document.
 preserve-ws?
	a boolean indicating if we are within a whitespace-preserving
      environment. If #t, suppress paragraph detection.
 str-handler
	a STR-HANDLER, see read-verbatim-body
 seed

 result of the last invocation of STR-HANDLER, or the original seed if
 STR-HANDLER was never called.

 read-char-data port expect-eof? preserve-ws? str-handler seed
 one of end-chars
 only if expect-eof?
 Always significant, unless directly before an end token.
 procedure+:	assert-token TOKEN KIND NAME
========================================================================
 These parsers are a set of syntactic forms to instantiate a SSAX
 parser. The user tells what to do with the parsed character and
 element data. These latter handlers determine if the parsing follows a
 character content or children elements. The parser is typically
 applied to the root element of a document.
 fdown
	procedure COMMAND ARGUMENTS EXPECTED-CONTENT SEED

	This procedure is to generate the seed to be passed to handlers
	that process the content of the element. This is the function
	identified as 'fdown' in the denotational semantics of the XML

 fup
	procedure COMMAND ARGUMENTS PARENT-SEED SEED

	This procedure is called when parsing of COMMAND is finished.
	The SEED is the result from the last content parser (or from
	same seed as was passed to fdown. The procedure is to generate a
	seed that will be the result of the element parser. This is the
	function identified as 'fup' in the denotational semantics of

 str-handler
	A STR-HANDLER, see read-verbatim-body

 The generated parser is a
	procedure COMMAND PORT SEED

 The procedure must be called *after* the command token has been read.
 empty or finished by complete-start-command
 Even if we have an @, it might be inline -- check
 that later
 this is only @-commands that escape
 characters: @}, @@, @{ -- new para if need-break
 The end will only have a name if it's for an
 environment
 examine valid paragraphs?
 Recurse for include files
 Start of an @-command
 procedure: reverse-collect-str-drop-ws fragments

 Given the list of fragments (some of which are text strings), reverse
 the list and concatenate adjacent text strings. We also drop
 "unsignificant" whitespace, that is, whitespace in front, behind and
 between elements. The whitespace that is included in character data
 is not affected.
 a shortcut
 another shortcut
 remove single ws-only string
 remove leading ws
 remove trailing whitespace
 replace interstitial ws with
 fdown
 fup
 str-handler
 duplicate arguments->attlist to avoid unnecessary splitting
 perhaps parse-environment-args should be named more
 generically.
 procedure: texi-fragment->stexi STRING


 *fragment*.
 procedure: texi->stexi PORT

 representation of the texinfo document ready to be read at PORT.

 first character after the @bye, or to the end of the file.
 same depth
 a symbol
 Replace % with texinfo-arguments.
 texinfo.scm ends here
  ( texinfo ) -- parsing of texinfo into SXML
 	 Copyright ( C ) 2009 , 2010 , 2011 , 2012 , 2013 , 2014   Free Software Foundation , Inc.
     Copyright ( C ) 2004 , 2009   < wingo at pobox dot com >
     Copyright ( C ) 2001,2002 Oleg Kiselyov < oleg at pobox dot com >
  This file is based on  's SSAX.scm .
  version 3 of the License , or ( at your option ) any later version .
  You should have received a copy of the GNU Lesser General Public
  Foundation , Inc. , 51 Franklin Street , Fifth Floor , Boston ,     USA

    processing in scheme
  This module parses texinfo into SXML .  will always be the
  processing that integrates texinfo into the constellation of SXML
  @subheading Notes on the SXML vocabulary
  the content . However , texinfo allows for @@-commands within the
  texinfo ` ` attributes '' are PCDATA . XML attributes , on the other hand ,
  are CDATA . For this reason , ` ` attributes '' of texinfo @@-commands are
  Because ` % ' is not a valid NCName , stexinfo is a superset of SXML . In

  Comparison to xml output of texinfo ( which is rather undocumented ):
   Does n't conform to  
   Slower ( although with caching the SXML that problem can go away )
    go in a dedicated element , FBOFW

  TODO

(define-module (texinfo)
  #:use-module (sxml simple)
  #:use-module (sxml transform)
  #:use-module (sxml ssax input-parse)
  #:use-module (srfi srfi-1)
  #:use-module (srfi srfi-11)
  #:use-module (srfi srfi-13)
  #:export (call-with-file-and-dir
            texi-command-specs
            texi-command-depth
            texi-fragment->stexi
            texi->stexi
            stexi->sxml))


(define (parser-error port message . rest)
  (apply throw 'parser-error port message rest))

(define (call-with-file-and-dir filename proc)
  "Call the one-argument procedure @var{proc} with an input port that
reads from @var{filename}. During the dynamic extent of @var{proc}'s
execution, the current directory will be @code{(dirname
@var{filename})}. This is useful for parsing documents that can include
files by relative path name."
  (let ((current-dir (getcwd)))
    (dynamic-wind
        (lambda () (chdir (dirname filename)))
        (lambda ()
          (call-with-input-file (basename filename) proc))
        (lambda () (chdir current-dir)))))

             Reflection on the XML vocabulary

(define texi-command-specs
"A list of (@var{name} @var{content-model} . @var{args})

@table @var
@item name 
The name of an @@-command, as a symbol.

@item content-model
A symbol indicating the syntactic type of the @@-command:
@table @code
@item EMPTY-COMMAND
No content, and no @code{@@end} is coming
@item EOL-ARGS
Unparsed arguments until end of line
@item EOL-TEXT
Parsed arguments until end of line
@item INLINE-ARGS
Unparsed arguments ending with @code{#\\@}}
@item INLINE-TEXT
Parsed arguments ending with @code{#\\@}}
@item INLINE-TEXT-ARGS
Parsed arguments ending with @code{#\\@}}
@item ENVIRON
The tag is an environment tag, expect @code{@@end foo}.
@item TABLE-ENVIRON
Like ENVIRON, but with special parsing rules for its arguments.
@item FRAGMENT
For @code{*fragment*}, the command used for parsing fragments of
texinfo documents.
@end table

@code{INLINE-TEXT} commands will receive their arguments within their
bodies, whereas the @code{-ARGS} commands will receive them in their
attribute list.

@code{EOF-TEXT} receives its arguments in its body.

@code{ENVIRON} commands have both: parsed arguments until the end of
line, received through their attribute list, and parsed text until the
@code{@@end}, received in their bodies.

@code{EOF-TEXT-ARGS} receives its arguments in its attribute list, as in
@code{ENVIRON}.

In addition, @code{ALIAS} can alias one command to another.  The alias
will never be seen in parsed stexinfo.

There are four @@-commands that are treated specially. @code{@@include}
is a low-level token that will not be seen by higher-level parsers, so
it has no content-model. @code{@@para} is the paragraph command, which
is only implicit in the texinfo source. @code{@@item} has special
syntax, as noted above, and @code{@@entry} is how this parser treats
@code{@@item} commands within @code{@@table}, @code{@@ftable}, and
@code{@@vtable}.

Also, indexing commands (@code{@@cindex}, etc.) are treated specially.
Their arguments are parsed, but they are needed before entering the
element so that an anchor can be inserted into the text before the index
entry.

@item args
Named arguments to the command, in the same format as the formals for a
lambda. Only present for @code{INLINE-ARGS}, @code{EOL-ARGS},
@code{INLINE-TEXT-ARGS}, @code{ENVIRON}, @code{TABLE-ENVIRON} commands.
@end table"
    (para               PARAGRAPH)
    (item               ITEM)
    (entry              ENTRY . heading)
    (noindent           EMPTY-COMMAND)
    (*fragment*         FRAGMENT)

    (bold               INLINE-TEXT)
    (sample             INLINE-TEXT)
    (samp               INLINE-TEXT)
    (code               INLINE-TEXT)
    (math               INLINE-TEXT)
    (kbd                INLINE-TEXT)
    (key                INLINE-TEXT)
    (var                INLINE-TEXT)
    (env                INLINE-TEXT)
    (file               INLINE-TEXT)
    (command            INLINE-TEXT)
    (option             INLINE-TEXT)
    (dfn                INLINE-TEXT)
    (cite               INLINE-TEXT)
    (acro               INLINE-TEXT)
    (email              INLINE-TEXT)
    (emph               INLINE-TEXT)
    (strong             INLINE-TEXT)
    (sample             INLINE-TEXT)
    (sc                 INLINE-TEXT)
    (titlefont          INLINE-TEXT)
    (asis               INLINE-TEXT)
    (b                  INLINE-TEXT)
    (i                  INLINE-TEXT)
    (r                  INLINE-TEXT)
    (sansserif          INLINE-TEXT)
    (slanted            INLINE-TEXT)
    (t                  INLINE-TEXT)

    (value              INLINE-ARGS . (key))
    (ref                INLINE-ARGS . (node #:opt name section info-file manual))
    (xref               INLINE-ARGS . (node #:opt name section info-file manual))
    (pxref              INLINE-TEXT-ARGS
                        . (node #:opt name section info-file manual))
    (url                ALIAS       . uref)
    (uref               INLINE-TEXT-ARGS . (url #:opt title replacement))
    (anchor             INLINE-ARGS . (name))
    (dots               INLINE-ARGS . ())
    (result             INLINE-ARGS . ())
    (bullet             INLINE-ARGS . ())
    (copyright          INLINE-ARGS . ())
    (tie                INLINE-ARGS . ())
    (image              INLINE-ARGS . (file #:opt width height alt-text extension))

    (acronym            INLINE-TEXT-ARGS . (acronym #:opt meaning))

  EOL args elements
    (node               EOL-ARGS . (name #:opt next previous up))
    (c                  EOL-ARGS . all)
    (comment            EOL-ARGS . all)
    (setchapternewpage  EOL-ARGS . all)
    (sp                 EOL-ARGS . all)
    (page               EOL-ARGS . ())
    (vskip              EOL-ARGS . all)
    (syncodeindex       EOL-ARGS . all)
    (contents           EOL-ARGS . ())
    (shortcontents      EOL-ARGS . ())
    (summarycontents    EOL-ARGS . ())
    (insertcopying      EOL-ARGS . ())
    (dircategory        EOL-ARGS . (category))
    (top		EOL-ARGS . (title))
    (printindex		EOL-ARGS . (type))
    (paragraphindent    EOL-ARGS . (indent))

  EOL text commands
    (*ENVIRON-ARGS*     EOL-TEXT)
    (itemx              EOL-TEXT)
    (set                EOL-TEXT)
    (center             EOL-TEXT)
    (title              EOL-TEXT)
    (subtitle           EOL-TEXT)
    (author             EOL-TEXT)
    (chapter            EOL-TEXT)
    (section            EOL-TEXT)
    (appendix           EOL-TEXT)
    (appendixsec        EOL-TEXT)
    (unnumbered         EOL-TEXT)
    (unnumberedsec      EOL-TEXT)
    (subsection         EOL-TEXT)
    (subsubsection      EOL-TEXT)
    (appendixsubsec     EOL-TEXT)
    (appendixsubsubsec  EOL-TEXT)
    (unnumberedsubsec   EOL-TEXT)
    (unnumberedsubsubsec EOL-TEXT)
    (chapheading        EOL-TEXT)
    (majorheading       EOL-TEXT)
    (heading            EOL-TEXT)
    (subheading         EOL-TEXT)
    (subsubheading      EOL-TEXT)

    (deftpx             EOL-TEXT-ARGS . (category name . attributes))
    (defcvx             EOL-TEXT-ARGS . (category class name))
    (defivarx           EOL-TEXT-ARGS . (class name))
    (deftypeivarx       EOL-TEXT-ARGS . (class data-type name))
    (defopx             EOL-TEXT-ARGS . (category class name . arguments))
    (deftypeopx         EOL-TEXT-ARGS . (category class data-type name . arguments))
    (defmethodx         EOL-TEXT-ARGS . (class name . arguments))
    (deftypemethodx     EOL-TEXT-ARGS . (class data-type name . arguments))
    (defoptx            EOL-TEXT-ARGS . (name))
    (defvrx             EOL-TEXT-ARGS . (category name))
    (defvarx            EOL-TEXT-ARGS . (name))
    (deftypevrx         EOL-TEXT-ARGS . (category data-type name))
    (deftypevarx        EOL-TEXT-ARGS . (data-type name))
    (deffnx             EOL-TEXT-ARGS . (category name . arguments))
    (deftypefnx         EOL-TEXT-ARGS . (category data-type name . arguments))
    (defspecx           EOL-TEXT-ARGS . (name . arguments))
    (defmacx            EOL-TEXT-ARGS . (name . arguments))
    (defunx             EOL-TEXT-ARGS . (name . arguments))
    (deftypefunx        EOL-TEXT-ARGS . (data-type name . arguments))

    (cindex             INDEX . entry)
    (findex             INDEX . entry)
    (vindex             INDEX . entry)
    (kindex             INDEX . entry)
    (pindex             INDEX . entry)
    (tindex             INDEX . entry)

    (texinfo            ENVIRON . title)
    (ignore             ENVIRON . ())
    (ifinfo             ENVIRON . ())
    (iftex              ENVIRON . ())
    (ifhtml             ENVIRON . ())
    (ifxml              ENVIRON . ())
    (ifplaintext        ENVIRON . ())
    (ifnotinfo          ENVIRON . ())
    (ifnottex           ENVIRON . ())
    (ifnothtml          ENVIRON . ())
    (ifnotxml           ENVIRON . ())
    (ifnotplaintext     ENVIRON . ())
    (titlepage          ENVIRON . ())
    (menu               ENVIRON . ())
    (direntry           ENVIRON . ())
    (copying            ENVIRON . ())
    (example            ENVIRON . ())
    (smallexample       ENVIRON . ())
    (display            ENVIRON . ())
    (smalldisplay       ENVIRON . ())
    (verbatim           ENVIRON . ())
    (format             ENVIRON . ())
    (smallformat        ENVIRON . ())
    (lisp               ENVIRON . ())
    (smalllisp          ENVIRON . ())
    (cartouche          ENVIRON . ())
    (quotation          ENVIRON . ())

    (deftp              ENVIRON . (category name . attributes))
    (defcv              ENVIRON . (category class name))
    (defivar            ENVIRON . (class name))
    (deftypeivar        ENVIRON . (class data-type name))
    (defop              ENVIRON . (category class name . arguments))
    (deftypeop          ENVIRON . (category class data-type name . arguments))
    (defmethod          ENVIRON . (class name . arguments))
    (deftypemethod      ENVIRON . (class data-type name . arguments))
    (defopt             ENVIRON . (name))
    (defvr              ENVIRON . (category name))
    (defvar             ENVIRON . (name))
    (deftypevr          ENVIRON . (category data-type name))
    (deftypevar         ENVIRON . (data-type name))
    (deffn              ENVIRON . (category name . arguments))
    (deftypefn          ENVIRON . (category data-type name . arguments))
    (defspec            ENVIRON . (name . arguments))
    (defmac             ENVIRON . (name . arguments))
    (defun              ENVIRON . (name . arguments))
    (deftypefun         ENVIRON . (data-type name . arguments))

    (table              TABLE-ENVIRON . (formatter))
    (itemize            TABLE-ENVIRON . (formatter))
    (enumerate          TABLE-ENVIRON . (start))
    (ftable             TABLE-ENVIRON . (formatter))
    (vtable             TABLE-ENVIRON . (formatter))))

(define command-depths
  '((chapter . 1) (section . 2) (subsection . 3) (subsubsection . 4)
    (top . 0) (unnumbered . 1) (unnumberedsec . 2)
    (unnumberedsubsec . 3) (unnumberedsubsubsec . 4)
    (appendix . 1) (appendixsec . 2) (appendixsection . 2)
    (appendixsubsec . 3) (appendixsubsubsec . 4)))
(define (texi-command-depth command max-depth)
  "Given the texinfo command @var{command}, return its nesting level, or
@code{#f} if it nests too deep for @var{max-depth}.

Examples:
@example
 (texi-command-depth 'chapter 4)        @result{} 1
 (texi-command-depth 'top 4)            @result{} 0
 (texi-command-depth 'subsection 4)     @result{} 3
 (texi-command-depth 'appendixsubsec 4) @result{} 3
 (texi-command-depth 'subsection 2)     @result{} #f
@end example"
  (let ((depth (and=> (assq command command-depths) cdr)))
    (and depth (<= depth max-depth) depth)))

(define (space-significant? command)
  (memq command
        '(example smallexample verbatim lisp smalllisp menu %)))

  Like a DTD for texinfo
(define (command-spec command)
  (let ((spec (assq command texi-command-specs)))
    (cond
     ((not spec)
      (parser-error #f "Unknown command" command))
     ((eq? (cadr spec) 'ALIAS)
      (command-spec (cddr spec)))
     (else
      spec))))

(define (inline-content? content)
  (case content
    ((INLINE-TEXT INLINE-ARGS INLINE-TEXT-ARGS) #t)
    (else #f)))



(define (string-whitespace? str)
  (or (string-null? str)
      (string-every char-whitespace? str)))

  Like read - text - line , but allows EOF .
(define read-eof-breaks '(*eof* #\return #\newline))
(define (read-eof-line port)
  (if (eof-object? (peek-char port))
      (peek-char port)
      (let* ((line (next-token '() read-eof-breaks
                               "reading a line" port))
  must be either  or \r or EOF
        (if (and (eq? c #\return) (eq? (peek-char port) #\newline))
  skip  that follows \r
        line)))

(define (skip-whitespace port)
  (skip-while '(#\space #\tab #\return #\newline) port))

(define (skip-horizontal-whitespace port)
  (skip-while '(#\space #\tab) port))


(define (read-command port)
  (let ((first-char (peek-char port)))
    (or (char-alphabetic? first-char)
        (parser-error port "Nonalphabetic @-command char: '" first-char "'")))
  (string->symbol
    (next-token-of
      (lambda (c)
        (cond
          ((eof-object? c) #f)
          ((char-alphabetic? c) c)
          (else #f)))
      port)))

  A token is a primitive lexical unit . It is a record with two fields ,
       START    The start of a texinfo command . The token - head will be a
       ITEM      commands have an irregular syntax . They end at the

(define (make-token kind head) (cons kind head))
(define token? pair?)
(define token-kind car)
(define token-head cdr)

  position in the stream must be # \@. This procedure scans enough of

(define (read-command-token port)
  (assert-curr-char '(#\@) "start of the command" port)
  (let ((peeked (peek-char port)))
    (cond
     ((memq peeked '(#\! #\: #\. #\? #\@ #\\ #\{ #\}))
  @-commands that escape characters
      (make-token 'STRING (string (read-char port))))
     (else
      (let ((name (read-command port)))
        (case name
          ((end)
           (let ((command (string-trim-both
                           (read-eof-line port))))
             (or (and (not (string-null? command))
                      (string-every char-alphabetic? command))
                 (parser-error port "malformed @end" command))
             (make-token 'END (string->symbol command))))
          ((bye)
           (make-token 'END 'texinfo))
          ((item)
           (make-token 'ITEM 'item))
          ((include)
           (make-token 'INCLUDE #f))
          (else
           (make-token 'START name))))))))

  must be the first position of the verbatim body . This function reads
  The first STRING1 argument to STR - HANDLER never contains a newline .
  The second STRING2 argument often will . On the first invocation of the
  as the third argument . The result of this first invocation will be
  passed as the seed argument to the second invocation of the line

(define (read-verbatim-body port str-handler seed)
  (let loop ((seed seed))
    (let ((fragment (next-token '() '(#\newline)
                                "reading verbatim" port)))
      (read-char port)
      (if (string=? fragment "@end verbatim")
          seed
          (loop (str-handler fragment "\n" seed))))))

  This procedure reads and parses a production ArgumentList .
  ArgumentList : : = S * Argument ( S * , S * Argument ) * S *
  Arguments are the things in braces , i.e @ref{my node } has one
  Whitespace around an Argument is trimmed .

(define (read-arguments port stop-char)
  (define (split str)
    (let ((ret (map (lambda (x) (if (string-null? x) #f x))
                    (map string-trim-both (string-split str #\,)))))
      (if (and (pair? ret) (eq? (car ret) #f) (null? (cdr ret)))
          '()
          ret)))
  (split (next-token '() (list stop-char)
                     "arguments of @-command" port)))

  TAG - NAME .
  Content model      Port position
  INLINE - TEXT        One character after the # \ { .
  INLINE - TEXT - ARGS   One character after the # \ { .
  INLINE - ARGS        The first character after the # \ } .
  EOL - TEXT           The first non - whitespace character after the command .
  ENVIRON , TABLE - ENVIRON , EOL - ARGS , EOL - TEXT
                    The first character on the next line .
  PARAGRAPH , ITEM , EMPTY - COMMAND
                    The first character after the command .

(define (arguments->attlist port args arg-names)
  (let loop ((in args) (names arg-names) (opt? #f) (out '()))
    (cond
      (reverse (if (null? in) out (acons names in out))))
     ((and (not (null? names)) (eq? (car names) #:opt))
      (loop in (cdr names) #t out))
     ((null? in)
      (if (or (null? names) opt?)
          (reverse out)
          (parser-error port "@-command expected more arguments:" 
                        args arg-names names)))
     ((null? names)
      (parser-error port "@-command didn't expect more arguments:" in))
     ((not (car in))
      (or (and opt? (loop (cdr in) (cdr names) opt? out))
          (parser-error "@-command missing required argument"
                        (car names))))
     (else
      (loop (cdr in) (cdr names) opt?
            (acons (car names)
                   (if (list? (car in)) (car in) (list (car in)))
                   out))))))

(define (parse-table-args command port)
  (let* ((line (string-trim-both (read-text-line port)))
         (length (string-length line)))
    (define (get-formatter)
      (or (and (not (zero? length))
               (eq? (string-ref line 0) #\@)
               (let ((f (string->symbol (substring line 1))))
                 (or (inline-content? (cadr (command-spec f)))
                     (parser-error
                      port "@item formatter must be INLINE" f))
                 f))
          (parser-error port "Invalid @item formatter" line)))
    (case command
      ((enumerate)
       (if (zero? length)
           '()
           `((start
              ,(if (or (and (eq? length 1)
                            (char-alphabetic? (string-ref line 0)))
                       (string-every char-numeric? line))
                   line
                   (parser-error
                    port "Invalid enumerate start" line))))))
      ((itemize)
       `((bullet
          ,(or (and (eq? length 1) line)
               (and (string-null? line) '(bullet))
               (list (get-formatter))))))
       `((formatter (,(get-formatter))))))))

(define (complete-start-command command port)
  (define (get-arguments type arg-names stop-char)
    (arguments->attlist port (read-arguments port stop-char) arg-names))

  (let* ((spec (command-spec command))
         (command (car spec))
         (type (cadr spec))
         (arg-names (cddr spec)))
    (case type
      ((INLINE-TEXT)
       (assert-curr-char '(#\{) "Inline element lacks {" port)
       (values command '() type))
      ((INLINE-ARGS)
       (assert-curr-char '(#\{) "Inline element lacks {" port)
       (values command (get-arguments type arg-names #\}) type))
      ((INLINE-TEXT-ARGS)
       (assert-curr-char '(#\{) "Inline element lacks {" port)
       (values command '() type))
      ((EOL-ARGS)
       (values command (get-arguments type arg-names #\newline) type))
      ((ENVIRON ENTRY INDEX)
       (skip-horizontal-whitespace port)
       (values command (parse-environment-args command port) type))
      ((TABLE-ENVIRON)
       (skip-horizontal-whitespace port)
       (values command (parse-table-args command port) type))
      ((EOL-TEXT)
       (skip-horizontal-whitespace port)
       (values command '() type))
      ((EOL-TEXT-ARGS)
       (skip-horizontal-whitespace port)
       (values command (parse-eol-text-args command port) type))
      ((PARAGRAPH EMPTY-COMMAND ITEM FRAGMENT)
       (values command '() type))
       (parser-error port "can't happen")))))

  They parse productions corresponding entire @-commands .

  Only reads @settitle , leaves it to the command parser to finish
(define (take-until-settitle port)
  (or (find-string-from-port? "\n@settitle " port)
      (parser-error port "No \\n@settitle  found"))
  (skip-horizontal-whitespace port)
  (and (eq? (peek-char port) #\newline)
       (parser-error port "You have a @settitle, but no title")))

  This procedure is to read the CharData of a texinfo document .
  text : : = ( CharData | Command ) *
  The procedure reads CharData and stops at @-commands ( or
	 a boolean indicating if EOF is normal , i.e. , the character
	 data may be terminated by the EOF . EOF is normal
	 an argument passed to the first invocation of STR - HANDLER .
  The procedure returns two results : SEED and TOKEN . The SEED is the
  TOKEN can be either an eof - object ( this can happen only if expect - eof ?
  was # t ) , or a texinfo token denoting the start or end of a tag .

(define read-char-data
  (let* ((end-chars-eof '(*eof* #\{ #\} #\@ #\newline)))
    (define (handle str-handler str1 str2 seed)
      (if (and (string-null? str1) (string-null? str2))
          seed
          (str-handler str1 str2 seed)))

    (lambda (port expect-eof? preserve-ws? str-handler seed)
      (let ((end-chars ((if expect-eof? identity cdr) end-chars-eof)))
        (let loop ((seed seed))
          (let* ((fragment (next-token '() end-chars "reading char data" port))
            (cond
              (values (handle str-handler fragment "" seed) term-char))
             ((memq term-char '(#\@ #\{ #\}))
              (values (handle str-handler fragment "" seed)
                      (case term-char
                        ((#\@) (read-command-token port))
                        ((#\{) (make-token 'START '*braces*))
                        ((#\}) (read-char port) (make-token 'END #f)))))
             ((eq? term-char #\newline)
              (let ((c (peek-next-char port)))
                (cond
                 ((eof-object? c)
                  (or expect-eof?
                      (parser-error port "EOF while reading char data"))
                  (values (handle str-handler fragment "" seed) c))
                 ((eq? c #\@)
                  (let* ((token (read-command-token port))
                         (end? (eq? (token-kind token) 'END)))
                    (values
                     (handle str-handler fragment
                             (if end? "" (if preserve-ws? "\n" " "))
                             seed)
                     token)))
                 ((and (not preserve-ws?) (eq? c #\newline))
  paragraph - separator : : = # \newline # \newline+
                  (skip-while '(#\newline) port)
                  (skip-horizontal-whitespace port)
                  (values (handle str-handler fragment "" seed)
                          (make-token 'PARA 'para)))
                 (else
                  (loop (handle str-handler fragment
                                (if preserve-ws? "\n" " ") seed)))))))))))))

  Make sure that TOKEN is of anticipated KIND and has anticipated NAME
(define (assert-token token kind name)
  (or (and (token? token)
           (eq? kind (token-kind token))
           (equal? name (token-head token)))
      (parser-error #f "Expecting @end for " name ", got " token)))

		 Highest - level parsers : Texinfo to SXML

  SAX or a DOM model .

  syntax : make - command - parser fdown    

  Create a parser to parse and process one element , including its

	 parser given in the title comments to (   ) .
	 fdown if the element has the empty content ) . PARENT - SEED is the
	 the XML parser given in the title comments to (   ) .


(define (read-include-file-name port)
  (let ((x (string-trim-both (read-eof-line port))))
    (if (string-null? x)
        (error "no file listed")
  fixme : should expand @value { } references

(define (sxml->node-name sxml)
  "Turn some sxml string into a valid node name."
  (let loop ((in (string->list (sxml->string sxml))) (out '()))
    (if (null? in)
        (apply string (reverse out))
        (if (memq (car in) '(#\{ #\} #\@ #\,))
            (loop (cdr in) out)
            (loop (cdr in) (cons (car in) out))))))

(define (index command arguments fdown fup parent-seed)
  (case command
    ((deftp defcv defivar deftypeivar defop deftypeop defmethod
      deftypemethod defopt defvr defvar deftypevr deftypevar deffn
      deftypefn defspec defmac defun deftypefun)
     (let ((args `((name ,(string-append (symbol->string command) "-"
                                         (cadr (assq 'name arguments)))))))
       (fup 'anchor args parent-seed
            (fdown 'anchor args 'INLINE-ARGS '()))))
    ((cindex findex vindex kindex pindex tindex)
     (let ((args `((name ,(string-append (symbol->string command) "-"
                                         (sxml->node-name
                                          (assq 'entry arguments)))))))
       (fup 'anchor args parent-seed
            (fdown 'anchor args 'INLINE-ARGS '()))))
    (else parent-seed)))

(define (make-command-parser fdown fup str-handler)
  (lambda (command port seed)
    (let visit ((command command) (port port) (sig-ws? #f) (parent-seed seed))
      (let*-values (((command arguments expected-content)
                     (complete-start-command command port)))
        (let* ((parent-seed (index command arguments fdown fup parent-seed))
               (seed (fdown command arguments expected-content parent-seed))
               (eof-closes? (or (memq command '(texinfo para *fragment*))
                                (eq? expected-content 'EOL-TEXT)))
               (sig-ws? (or sig-ws? (space-significant? command)))
               (up (lambda (s) (fup command arguments parent-seed s)))
               (new-para (lambda (s) (fdown 'para '() 'PARAGRAPH s)))
               (make-end-para (lambda (p) (lambda (s) (fup 'para '() p s)))))
          
          (define (port-for-content)
            (if (eq? expected-content 'EOL-TEXT)
                (call-with-input-string (read-text-line port) identity)
                port))

          (cond
           ((memq expected-content '(EMPTY-COMMAND INLINE-ARGS EOL-ARGS INDEX
                                     EOL-TEXT-ARGS))
            (up seed))
           ((eq? command 'verbatim)
            (up (read-verbatim-body port str-handler seed)))
           (else
            (let loop ((port (port-for-content))
                       (expect-eof? eof-closes?)
                       (end-para identity)
                       (need-break? (and (not sig-ws?)
                                         (memq expected-content
                                               '(ENVIRON TABLE-ENVIRON
                                                 ENTRY ITEM FRAGMENT))))
                       (seed seed))
              (cond
               ((and need-break? (or sig-ws? (skip-whitespace port))
                     (not (memq (peek-char port) '(#\@ #\})))
                     (not (eof-object? (peek-char port))))
                (let ((seed (end-para seed)))
                  (loop port expect-eof? (make-end-para seed) #f
                        (new-para seed))))
               (else
                (let*-values (((seed token)
                               (read-char-data
                                port expect-eof? sig-ws? str-handler seed)))
                  (cond
                   ((eof-object? token)
                    (case expect-eof? 
                      ((include #f) (end-para seed))
                      (else (up (end-para seed)))))
                   (else
                    (case (token-kind token)
                      ((STRING)
                       (let ((seed ((if need-break? end-para identity) seed)))
                         (loop port expect-eof?
                               (if need-break? (make-end-para seed) end-para) #f
                               (str-handler (token-head token) ""
                                            ((if need-break? new-para identity)
                                             seed)))))
                      ((END)
                       (cond
                        ((memq command '(item entry))
                         (let ((spec (command-spec (token-head token))))
                           (or (eq? (cadr spec) 'TABLE-ENVIRON)
                               (parser-error
                                port "@item not ended by @end table/enumerate/itemize"
                                token))))
                        ((eq? expected-content 'ENVIRON)
                         (assert-token token 'END command)))
                       (up (end-para seed)))
                      ((ITEM)
                       (cond
                        ((memq command '(enumerate itemize))
                         (up (visit 'item port sig-ws? (end-para seed))))
                        ((eq? expected-content 'TABLE-ENVIRON)
                         (up (visit 'entry port sig-ws? (end-para seed))))
                        ((memq command '(item entry))
                         (visit command port sig-ws? (up (end-para seed))))
                        (else
                         (parser-error
                          port "@item must be within a table environment"
                          command))))
                      ((PARA)
                       (loop port expect-eof? end-para (not sig-ws?) seed))
                      ((INCLUDE)
                       (let ((seed (call-with-file-and-dir
                                    (read-include-file-name port)
                                    (lambda (port)
                                      (loop port 'include end-para
                                            need-break? seed)))))
                         (loop port expect-eof? end-para need-break? seed)))
                       (let* ((head (token-head token))
                              (spec (command-spec head))
                              (head (car spec))
                              (type (cadr spec))
                              (inline? (inline-content? type))
                              (seed ((if (and inline? (not need-break?))
                                         identity end-para) seed))
                              (end-para (if inline?
                                            (if need-break? (make-end-para seed)
                                                end-para)
                                            identity))
                              (new-para (if (and inline? need-break?)
                                            new-para identity)))
                         (loop port expect-eof? end-para (not inline?)
                               (visit head port sig-ws? (new-para seed)))))
                      (else
                       (parser-error port "Unknown token type" token))))))))))))))))

(define (reverse-collect-str-drop-ws fragments)
  (cond 
    '())
         (string-whitespace? (car fragments)))
    '())
   (else
    (let loop ((fragments fragments) (result '()) (strs '())
               (all-whitespace? #t))
      (cond
       ((null? fragments)
        (if all-whitespace?
            (cons (apply string-append strs) result)))
       ((string? (car fragments))
        (loop (cdr fragments) result (cons (car fragments) strs)
              (and all-whitespace?
                   (string-whitespace? (car fragments)))))
       (else
        (loop (cdr fragments)
              (cons
               (car fragments)
               (cond
                ((null? strs) result)
                (all-whitespace?
                 (if (null? result)
  one space
                (else
                 (cons (apply string-append strs) result))))
              '() #t)))))))

(define (parse-inline-text-args port spec text)
  (let lp ((in text) (cur '()) (out '()))
    (cond
     ((null? in)
      (if (and (pair? cur)
               (string? (car cur))
               (string-whitespace? (car cur)))
          (lp in (cdr cur) out)
          (let ((args (reverse (if (null? cur)
                                   out
                                   (cons (reverse cur) out)))))
            (arguments->attlist port args (cddr spec)))))
     ((pair? (car in))
      (lp (cdr in) (cons (car in) cur) out))
     ((string-index (car in) #\,)
      (let* ((parts (string-split (car in) #\,))
             (head (string-trim-right (car parts)))
             (rev-tail (reverse (cdr parts)))
             (last (string-trim (car rev-tail))))
        (lp (cdr in)
            (if (string-null? last) cur (cons last cur))
            (append (cdr rev-tail)
                    (cons (reverse (if (string-null? head) cur (cons head cur)))
                          out)))))
     (else
      (lp (cdr in)
          (cons (if (null? cur) (string-trim (car in)) (car in)) cur)
          out)))))

(define (make-dom-parser)
  (make-command-parser
     '())
     (let* ((seed (reverse-collect-str-drop-ws seed))
            (spec (command-spec command))
            (command (car spec)))
       (if (eq? (cadr spec) 'INLINE-TEXT-ARGS)
           (cons (list command (cons '% (parse-inline-text-args #f spec seed)))
                 parent-seed)
           (acons command
                  (if (null? args) seed (acons '% args seed))
                  parent-seed))))
     (if (string-null? string2)
         (cons string1 seed)
         (cons* string2 string1 seed)))))

(define parse-environment-args
  (let ((parser (make-dom-parser)))
    (lambda (command port)
      (let* ((args (cdar (parser '*ENVIRON-ARGS* port '())))
             (spec (command-spec command))
             (command (car spec))
             (arg-names (cddr spec)))
        (cond
         ((not arg-names)
          (if (null? args) '()
              (parser-error port "@-command doesn't take args" command)))
         ((eq? arg-names #t)
          (list (cons 'arguments args)))
         (else
          (let loop ((args args) (arg-names arg-names) (out '()))
            (cond
             ((null? arg-names)
              (if (null? args) (reverse! out)
                  (parser-error port "@-command didn't expect more args"
                                command args)))
             ((symbol? arg-names)
              (reverse! (acons arg-names args out)))
             ((null? args)
              (parser-error port "@-command expects more args"
                            command arg-names))
             ((and (string? (car args)) (string-index (car args) #\space))
              => (lambda (i)
                   (let ((rest (substring/shared (car args) (1+ i))))
                     (if (zero? i)
                         (loop (cons rest (cdr args)) arg-names out)
                         (loop (cons rest (cdr args)) (cdr arg-names)
                               (cons (list (car arg-names)
                                           (substring (car args) 0 i))
                                     out))))))
             (else
              (loop (cdr args) (cdr arg-names)
                    (if (and (pair? (car args)) (eq? (caar args) '*braces*))
                        (acons (car arg-names) (cdar args) out)
                        (cons (list (car arg-names) (car args)) out))))))))))))
   
(define (parse-eol-text-args command port)
  (parse-environment-args command port))

  A DOM parser for a texinfo fragment STRING .
  The procedure returns an SXML tree headed by the special tag ,

(define (texi-fragment->stexi string-or-port)
  "Parse the texinfo commands in @var{string-or-port}, and return the
resultant stexi tree. The head of the tree will be the special command,
@code{*fragment*}."
  (define (parse port)
    (postprocess (car ((make-dom-parser) '*fragment* port '()))))
  (if (input-port? string-or-port)
      (parse string-or-port)
      (call-with-input-string string-or-port parse)))

  This is an instance of a SSAX parser above that returns an SXML
  The procedure returns an SXML tree . The port points to the

(define (texi->stexi port)
  "Read a full texinfo document from @var{port} and return the parsed
stexi tree. The parsing will start at the @code{@@settitle} and end at
@code{@@bye} or EOF."
  (let ((parser (make-dom-parser)))
    (take-until-settitle port)
    (postprocess (car (parser 'texinfo port '())))))

(define (car-eq? x y) (and (pair? x) (eq? (car x) y)))
(define (make-contents tree)
  (define (lp in out depth)
    (cond
     ((null? in) (values in (cons 'enumerate (reverse! out))))
     ((and (pair? (cdr in)) (texi-command-depth (caadr in) 4))
      => (lambda (new-depth)
           (let ((node-name (and (car-eq? (car in) 'node)
                                 (cadr (assq 'name (cdadar in))))))
             (cond
              ((< new-depth depth)
               (values in (cons 'enumerate (reverse! out))))
              ((> new-depth depth)
               (let ((out-cdr (if (null? out) '() (cdr out)))
                     (out-car (if (null? out) (list 'item) (car out))))
                 (let*-values (((new-in new-out) (lp in '() (1+ depth))))
                   (lp new-in
                       (cons (append out-car (list new-out)) out-cdr)
                       depth))))
               (lp (cddr in)
                   (cons
                    `(item (para
                            ,@(if node-name
                                  `((ref (% (node ,node-name))))
                                  (cdadr in))))
                    out)
                   depth))))))
     (else (lp (cdr in) out depth))))
  (let*-values (((_ contents) (lp tree '() 1)))
    `((chapheading "Table of Contents") ,contents)))

(define (trim-whitespace str trim-left? trim-right?)
  (let* ((left-space? (and (not trim-left?)
                           (string-prefix? " " str)))
         (right-space? (and (not trim-right?)
                            (string-suffix? " " str)))
         (tail (append! (string-tokenize str)
                        (if right-space? '("") '()))))
    (string-join (if left-space? (cons "" tail) tail))))

(define (postprocess tree)
  (define (loop in out state first? sig-ws?)
    (cond
     ((null? in)
      (values (reverse! out) state))
     ((string? (car in))
      (loop (cdr in)
            (cons (if sig-ws? (car in)
                      (trim-whitespace (car in) first? (null? (cdr in))))
                  out)
            state #f sig-ws?))
     ((pair? (car in))
      (case (caar in)
        ((set)
         (if (null? (cdar in)) (error "@set missing arguments" in))
         (if (string? (cadar in))
             (let ((i (string-index (cadar in) #\space)))
               (if i 
                   (loop (cdr in) out
                         (acons (substring (cadar in) 0 i)
                                (cons (substring (cadar in) (1+ i)) (cddar in))
                                state)
                         #f sig-ws?)
                   (loop (cdr in) out (acons (cadar in) (cddar in) state)
                         #f sig-ws?)))
             (error "expected a constant to define for @set" in)))
        ((value)
         (loop (fold-right cons (cdr in)
                           (or (and=>
                                (assoc (cadr (assq 'key (cdadar in))) state) cdr)
                               (error "unknown value" (cdadar in) state)))
               out
               state #f sig-ws?))
        ((copying)
         (loop (cdr in) out (cons (car in) state) #f sig-ws?))
        ((insertcopying)
         (loop (fold-right cons (cdr in)
                           (or (cdr (assoc 'copying state))
                               (error "copying isn't set yet")))
               out
               state #f sig-ws?))
        ((contents)
         (loop (cdr in) (fold cons out (make-contents tree)) state #f sig-ws?))
        (else
         (let*-values (((kid-out state)
                        (loop (car in) '() state #t
                              (or sig-ws? (space-significant? (caar in))))))
           (loop (cdr in) (cons kid-out out) state #f sig-ws?)))))
      (loop (cdr in) (cons (car in) out) state #t sig-ws?))))

  (call-with-values
      (lambda () (loop tree '() '() #t #f))
    (lambda (out state) out)))

(define (stexi->sxml tree)
  "Transform the stexi tree @var{tree} into sxml. This involves
replacing the @code{%} element that keeps the texinfo arguments with an
element for each argument.

FIXME: right now it just changes % to @code{texinfo-arguments} -- that
doesn't hang with the idea of making a dtd at some point"
  (pre-post-order
   tree
   `((% . ,(lambda (x . t) (cons 'texinfo-arguments t)))
     (*text* . ,(lambda (x t) t))
     (*default* . ,(lambda (x . t) (cons x t))))))

  arch - tag : 73890afa-597c-4264 - ae70 - 46fe7756ffb5
