text: /*
   * Copyright (c) 1985 Sun Microsystems, Inc.
   * Copyright (c) 1980, 1993
   *	The Regents of the University of California.  All rights reserved.
   * All rights reserved.
   *
   * 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.
   * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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.
   *
   * @(#)parse.c	8.1 (Berkeley) 6/6/93
   * $FreeBSD: src/usr.bin/indent/parse.c,v 1.10 2003/06/15 09:28:17 charnier Exp $
   */
  
  #include <stdio.h>
  #include "indent_globs.h"
  #include "indent_codes.h"
  #include "indent.h"
  
  static void reduce(void);
  
  void
  parse(int tk) /* tk: the code for the construct scanned */
  {
      int         i;
  
  #ifdef debug
      printf("%2d - %s\n", tk, token);
  #endif
  
      while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
  	/* true if we have an if without an else */
  	ps.p_stack[ps.tos] = stmt;	/* apply the if(..) stmt ::= stmt
  					 * reduction */
  	reduce();		/* see if this allows any reduction */
      }
  
  
      switch (tk) {		/* go on and figure out what to do with the
  				 * input */
  
      case decl:			/* scanned a declaration word */
  	ps.search_brace = btype_2;
  	/* indicate that following brace should be on same line */
  	if (ps.p_stack[ps.tos] != decl) {	/* only put one declaration
  						 * onto stack */
  	    break_comma = true;	/* while in declaration, newline should be
  				 * forced after comma */
  	    ps.p_stack[++ps.tos] = decl;
  	    ps.il[ps.tos] = ps.i_l_follow;
  
  	    if (ps.ljust_decl) {/* only do if we want left justified
  				 * declarations */
  		ps.ind_level = 0;
  		for (i = ps.tos - 1; i > 0; --i)
  		    if (ps.p_stack[i] == decl)
  			++ps.ind_level;	/* indentation is number of
  					 * declaration levels deep we are */
  		ps.i_l_follow = ps.ind_level;
  	    }
  	}
  	break;
  
      case ifstmt:		/* scanned if (...) */
  	if (ps.p_stack[ps.tos] == elsehead && ps.else_if)	/* "else if ..." */
  	    ps.i_l_follow = ps.il[ps.tos];
      case dolit:		/* 'do' */
      case forstmt:		/* for (...) */
  	ps.p_stack[++ps.tos] = tk;
  	ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
  	++ps.i_l_follow;	/* subsequent statements should be indented 1 */
  	ps.search_brace = btype_2;
  	break;
  
      case lbrace:		/* scanned { */
  	break_comma = false;	/* don't break comma in an initial list */
  	if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
  		|| ps.p_stack[ps.tos] == stmtl)
  	    ++ps.i_l_follow;	/* it is a random, isolated stmt group or a
  				 * declaration */
  	else {
  	    if (s_code == e_code) {
  		/*
  		 * only do this if there is nothing on the line
  		 */
  		--ps.ind_level;
  		/*
  		 * it is a group as part of a while, for, etc.
  		 */
  		if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
  		    --ps.ind_level;
  		/*
  		 * for a switch, brace should be two levels out from the code
  		 */
  	    }
  	}
  
  	ps.p_stack[++ps.tos] = lbrace;
  	ps.il[ps.tos] = ps.ind_level;
  	ps.p_stack[++ps.tos] = stmt;
  	/* allow null stmt between braces */
  	ps.il[ps.tos] = ps.i_l_follow;
  	break;
  
      case whilestmt:		/* scanned while (...) */
  	if (ps.p_stack[ps.tos] == dohead) {
  	    /* it is matched with do stmt */
  	    ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
  	    ps.p_stack[++ps.tos] = whilestmt;
  	    ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
  	}
  	else {			/* it is a while loop */
  	    ps.p_stack[++ps.tos] = whilestmt;
  	    ps.il[ps.tos] = ps.i_l_follow;
  	    ++ps.i_l_follow;
  	    ps.search_brace = btype_2;
  	}
  
  	break;
  
      case elselit:		/* scanned an else */
  
  	if (ps.p_stack[ps.tos] != ifhead)
  	    diag2(1, "Unmatched 'else'");
  	else {
  	    ps.ind_level = ps.il[ps.tos];	/* indentation for else should
  						 * be same as for if */
  	    ps.i_l_follow = ps.ind_level + 1;	/* everything following should
  						 * be in 1 level */
  	    ps.p_stack[ps.tos] = elsehead;
  	    /* remember if with else */
  	    ps.search_brace = btype_2 | ps.else_if;
  	}
  	break;
  
      case rbrace:		/* scanned a } */
  	/* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
  	if (ps.p_stack[ps.tos - 1] == lbrace) {
  	    ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
  	    ps.p_stack[ps.tos] = stmt;
  	}
  	else
  	    diag2(1, "Statement nesting error");
  	break;
  
      case swstmt:		/* had switch (...) */
  	ps.p_stack[++ps.tos] = swstmt;
  	ps.cstk[ps.tos] = case_ind;
  	/* save current case indent level */
  	ps.il[ps.tos] = ps.i_l_follow;
  	case_ind = ps.i_l_follow + ps.case_indent;	/* cases should be one
  							 * level down from
  							 * switch */
  	ps.i_l_follow += ps.case_indent + 1;	/* statements should be two
  						 * levels in */
  	ps.search_brace = btype_2;
  	break;
  
      case semicolon:		/* this indicates a simple stmt */
  	break_comma = false;	/* turn off flag to break after commas in a
  				 * declaration */
  	ps.p_stack[++ps.tos] = stmt;
  	ps.il[ps.tos] = ps.ind_level;
  	break;
  
      default:			/* this is an error */
  	diag2(1, "Unknown code to parser");
  	return;
  
  
      }				/* end of switch */
  
      reduce();			/* see if any reduction can be done */
  
  #ifdef debug
      for (i = 1; i <= ps.tos; ++i)
  	printf("(%d %d)", ps.p_stack[i], ps.il[i]);
      printf("\n");
  #endif
  
      return;
  }
  
  /*
   * NAME: reduce
   *
   * FUNCTION: Implements the reduce part of the parsing algorithm
   *
   * ALGORITHM: The following reductions are done.  Reductions are repeated
   *	until no more are possible.
   *
   * Old TOS		New TOS
   * <stmt> <stmt>	<stmtl>
   * <stmtl> <stmt>	<stmtl>
   * do <stmt>		"dostmt"
   * if <stmt>		"ifstmt"
   * switch <stmt>	<stmt>
   * decl <stmt>		<stmt>
   * "ifelse" <stmt>	<stmt>
   * for <stmt>		<stmt>
   * while <stmt>		<stmt>
   * "dostmt" while	<stmt>
   *
   * On each reduction, ps.i_l_follow (the indentation for the following line)
   * is set to the indentation level associated with the old TOS.
   *
   * PARAMETERS: None
   *
   * RETURNS: Nothing
   *
   * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
   *
   * CALLS: None
   *
   * CALLED BY: parse
   *
   * HISTORY: initial coding 	November 1976	D A Willcox of CAC
   *
   */
  /*----------------------------------------------*\
  |   REDUCTION PHASE				    |
  \*----------------------------------------------*/
  static void
  reduce(void)
  {
      int i;
  
      for (;;) {			/* keep looping until there is nothing left to
  				 * reduce */
  
  	switch (ps.p_stack[ps.tos]) {
  
  	case stmt:
  	    switch (ps.p_stack[ps.tos - 1]) {
  
  	    case stmt:
  	    case stmtl:
  		/* stmtl stmt or stmt stmt */
  		ps.p_stack[--ps.tos] = stmtl;
  		break;
  
  	    case dolit:	/* <do> <stmt> */
  		ps.p_stack[--ps.tos] = dohead;
  		ps.i_l_follow = ps.il[ps.tos];
  		break;
  
  	    case ifstmt:
  		/* <if> <stmt> */
  		ps.p_stack[--ps.tos] = ifhead;
  		for (i = ps.tos - 1;
  			(
  			 ps.p_stack[i] != stmt
  			 &&
  			 ps.p_stack[i] != stmtl
  			 &&
  			 ps.p_stack[i] != lbrace
  			 );
  			--i);
  		ps.i_l_follow = ps.il[i];
  		/*
  		 * for the time being, we will assume that there is no else on
  		 * this if, and set the indentation level accordingly. If an
  		 * else is scanned, it will be fixed up later
  		 */
  		break;
  
  	    case swstmt:
  		/* <switch> <stmt> */
  		case_ind = ps.cstk[ps.tos - 1];
  
  	    case decl:		/* finish of a declaration */
  	    case elsehead:
  		/* <<if> <stmt> else> <stmt> */
  	    case forstmt:
  		/* <for> <stmt> */
  	    case whilestmt:
  		/* <while> <stmt> */
  		ps.p_stack[--ps.tos] = stmt;
  		ps.i_l_follow = ps.il[ps.tos];
  		break;
  
  	    default:		/* <anything else> <stmt> */
  		return;
  
  	    }			/* end of section for <stmt> on top of stack */
  	    break;
  
  	case whilestmt:	/* while (...) on top */
  	    if (ps.p_stack[ps.tos - 1] == dohead) {
  		/* it is termination of a do while */
  		ps.tos -= 2;
  		break;
  	    }
  	    else
  		return;
  
  	default:		/* anything else on top */
  	    return;
  
  	}
      }
  }
  