xref: /src/usr.bin/indent/parse.c

/*	$NetBSD: parse.c,v 1.6 2002/05/26 22:53:38 wiz Exp $	*/

/*
 * Copyright (c) 1980, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1976 Board of Trustees of the University of Illinois.
 * Copyright (c) 1985 Sun Microsystems, Inc.
 * 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.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 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.
 */

#include <sys/cdefs.h>
#ifndef lint
#if 0
static char sccsid[] = "@(#)parse.c	8.1 (Berkeley) 6/6/93";
#else
__RCSID("$NetBSD: parse.c,v 1.6 2002/05/26 22:53:38 wiz Exp $");
#endif
#endif				/* not lint */

#include <stdio.h>
#include "indent_globs.h"
#include "indent_codes.h"

/* tk: the code for the construct scanned */
void
parse(int tk)
{
	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)
			diag(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
			diag(1, "Stmt 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 */
		diag(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
}
/*
 * 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				    |
\*----------------------------------------------*/
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.p_stack[--ps.tos] = stmt;
				break;
			} else
				return;

		default:	/* anything else on top */
			return;

		}
	}
}