;;;
;;; text.template - simple text templating
;;;
    Copyright ( c ) 2016 - 2022       <  >
;;;
;;;   Redistribution and use in source and binary forms, with or without
;;;   modification, are permitted provided that the following conditions
;;;   are met:
;;;
;;;   1. Redistributions of source code must retain the above copyright
;;;      notice, this list of conditions and the following disclaimer.
;;;
;;;   2. Redistributions in binary form must reproduce the above copyright
;;;      notice, this list of conditions and the following disclaimer in the
;;;      documentation and/or other materials provided with the distribution.
;;;
;;;   3. Neither the name of the authors nor the names of its contributors
;;;      may be used to endorse or promote products derived from this
;;;      software without specific prior written permission.
;;;
;;;   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
    " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT
;;;   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
;;;   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
;;;   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
    SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT LIMITED
;;;   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
;;;   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
    LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT ( INCLUDING
;;;   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
;;;   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
;;;

;; This module just uses string-interpolate feature to apply
;; runtime-provided text (template).  Most of the code is for
;; easy-to-use environment manipulation.

(define-module text.template
  (use gauche.dictionary)
  (use file.util)
  (export make-template-environment
          expand-template-string
          expand-template-file))
(select-module text.template)

(define-class <template-environment> ()
  (;; all slots are private
   (module  :init-keyword :module)))

(define (make-template-environment :key
                                   (extends '(gauche))
                                   (imports '())
                                   (bindings #f)) ; can be dict, or kv-list
  (make <template-environment>
    :module (setup-template-environment extends imports bindings)))

(define (setup-template-environment extends imports bindings)
  (rlet1 m (make-module #f)
    (dolist [i imports]
      (if (list? i)
        (eval `(import ,@i) m)
        (eval `(import ,i) m)))
    (cond
     [(is-a? bindings <dictionary>)
      (dict-for-each
       bindings
       (^[k v]
         (unless (symbol? k)
           (error "Symbol required for binding table key, but got:" k))
         (eval `(define ,k ',v) m)))]
     [(list? bindings)
      (do-plist ([k v] bindings)
        (unless (symbol? k)
          (error "Symbol required for binding table key, but got:" k))
         (eval `(define ,k ',v) m))]
     [(not bindings)]
     [else (error "Invalid bindings: a dictionary or kv-list expected, but got"
                  bindings)])
    (eval `(extend ,@extends) m)))

(define (expand-template-string text env)
  (assume-type env <template-environment>)
  (eval (string-interpolate text) (~ env'module)))

(define (expand-template-file filename env :optional (paths '()))
  (assume-type env <template-environment>)
  (if-let1 file (if (or (null? paths) (absolute-path? filename))
                  filename
                  (any (^p (let1 f (build-path p filename)
                             (and (file-exists? f) f)))
                       paths))
    (expand-template-string (file->string file) env)
    (errorf "Couldn't find template file ~s in ~s" filename paths)))


 text.template - simple text templating


   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:

   1. Redistributions of source code must retain the above copyright
      notice, this list of conditions and the following disclaimer.

   2. Redistributions in binary form must reproduce the above copyright
      notice, this list of conditions and the following disclaimer in the
      documentation and/or other materials provided with the distribution.

   3. Neither the name of the authors nor the names of its contributors
      may be used to endorse or promote products derived from this
      software without specific prior written permission.

   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 This module just uses string-interpolate feature to apply
 runtime-provided text (template).  Most of the code is for
 easy-to-use environment manipulation.
 all slots are private
 can be dict, or kv-list
    Copyright ( c ) 2016 - 2022       <  >
    " AS IS " AND ANY EXPRESS OR IMPLIED WARRANTIES , INCLUDING , BUT NOT
    SPECIAL , EXEMPLARY , OR CONSEQUENTIAL DAMAGES ( INCLUDING , BUT NOT LIMITED
    LIABILITY , WHETHER IN CONTRACT , STRICT LIABILITY , OR TORT ( INCLUDING


(define-module text.template
  (use gauche.dictionary)
  (use file.util)
  (export make-template-environment
          expand-template-string
          expand-template-file))
(select-module text.template)

(define-class <template-environment> ()
   (module  :init-keyword :module)))

(define (make-template-environment :key
                                   (extends '(gauche))
                                   (imports '())
  (make <template-environment>
    :module (setup-template-environment extends imports bindings)))

(define (setup-template-environment extends imports bindings)
  (rlet1 m (make-module #f)
    (dolist [i imports]
      (if (list? i)
        (eval `(import ,@i) m)
        (eval `(import ,i) m)))
    (cond
     [(is-a? bindings <dictionary>)
      (dict-for-each
       bindings
       (^[k v]
         (unless (symbol? k)
           (error "Symbol required for binding table key, but got:" k))
         (eval `(define ,k ',v) m)))]
     [(list? bindings)
      (do-plist ([k v] bindings)
        (unless (symbol? k)
          (error "Symbol required for binding table key, but got:" k))
         (eval `(define ,k ',v) m))]
     [(not bindings)]
     [else (error "Invalid bindings: a dictionary or kv-list expected, but got"
                  bindings)])
    (eval `(extend ,@extends) m)))

(define (expand-template-string text env)
  (assume-type env <template-environment>)
  (eval (string-interpolate text) (~ env'module)))

(define (expand-template-file filename env :optional (paths '()))
  (assume-type env <template-environment>)
  (if-let1 file (if (or (null? paths) (absolute-path? filename))
                  filename
                  (any (^p (let1 f (build-path p filename)
                             (and (file-exists? f) f)))
                       paths))
    (expand-template-string (file->string file) env)
    (errorf "Couldn't find template file ~s in ~s" filename paths)))
