parse.c revision 256281 
1/*
2 * Copyright (c) 1985 Sun Microsystems, Inc.
3 * Copyright (c) 1980, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgement:
17 *	This product includes software developed by the University of
18 *	California, Berkeley and its contributors.
19 * 4. Neither the name of the University nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#if 0
37#ifndef lint
38static char sccsid[] = "@(#)parse.c	8.1 (Berkeley) 6/6/93";
39#endif /* not lint */
40#endif
41
42#include <sys/cdefs.h>
43__FBSDID("$FreeBSD: stable/10/usr.bin/indent/parse.c 116390 2003-06-15 09:28:17Z charnier $");
44
45#include <stdio.h>
46#include "indent_globs.h"
47#include "indent_codes.h"
48#include "indent.h"
49
50static void reduce(void);
51
52void
53parse(int tk) /* tk: the code for the construct scanned */
54{
55    int         i;
56
57#ifdef debug
58    printf("%2d - %s\n", tk, token);
59#endif
60
61    while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
62	/* true if we have an if without an else */
63	ps.p_stack[ps.tos] = stmt;	/* apply the if(..) stmt ::= stmt
64					 * reduction */
65	reduce();		/* see if this allows any reduction */
66    }
67
68
69    switch (tk) {		/* go on and figure out what to do with the
70				 * input */
71
72    case decl:			/* scanned a declaration word */
73	ps.search_brace = btype_2;
74	/* indicate that following brace should be on same line */
75	if (ps.p_stack[ps.tos] != decl) {	/* only put one declaration
76						 * onto stack */
77	    break_comma = true;	/* while in declaration, newline should be
78				 * forced after comma */
79	    ps.p_stack[++ps.tos] = decl;
80	    ps.il[ps.tos] = ps.i_l_follow;
81
82	    if (ps.ljust_decl) {/* only do if we want left justified
83				 * declarations */
84		ps.ind_level = 0;
85		for (i = ps.tos - 1; i > 0; --i)
86		    if (ps.p_stack[i] == decl)
87			++ps.ind_level;	/* indentation is number of
88					 * declaration levels deep we are */
89		ps.i_l_follow = ps.ind_level;
90	    }
91	}
92	break;
93
94    case ifstmt:		/* scanned if (...) */
95	if (ps.p_stack[ps.tos] == elsehead && ps.else_if)	/* "else if ..." */
96	    ps.i_l_follow = ps.il[ps.tos];
97    case dolit:		/* 'do' */
98    case forstmt:		/* for (...) */
99	ps.p_stack[++ps.tos] = tk;
100	ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
101	++ps.i_l_follow;	/* subsequent statements should be indented 1 */
102	ps.search_brace = btype_2;
103	break;
104
105    case lbrace:		/* scanned { */
106	break_comma = false;	/* don't break comma in an initial list */
107	if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
108		|| ps.p_stack[ps.tos] == stmtl)
109	    ++ps.i_l_follow;	/* it is a random, isolated stmt group or a
110				 * declaration */
111	else {
112	    if (s_code == e_code) {
113		/*
114		 * only do this if there is nothing on the line
115		 */
116		--ps.ind_level;
117		/*
118		 * it is a group as part of a while, for, etc.
119		 */
120		if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
121		    --ps.ind_level;
122		/*
123		 * for a switch, brace should be two levels out from the code
124		 */
125	    }
126	}
127
128	ps.p_stack[++ps.tos] = lbrace;
129	ps.il[ps.tos] = ps.ind_level;
130	ps.p_stack[++ps.tos] = stmt;
131	/* allow null stmt between braces */
132	ps.il[ps.tos] = ps.i_l_follow;
133	break;
134
135    case whilestmt:		/* scanned while (...) */
136	if (ps.p_stack[ps.tos] == dohead) {
137	    /* it is matched with do stmt */
138	    ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
139	    ps.p_stack[++ps.tos] = whilestmt;
140	    ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
141	}
142	else {			/* it is a while loop */
143	    ps.p_stack[++ps.tos] = whilestmt;
144	    ps.il[ps.tos] = ps.i_l_follow;
145	    ++ps.i_l_follow;
146	    ps.search_brace = btype_2;
147	}
148
149	break;
150
151    case elselit:		/* scanned an else */
152
153	if (ps.p_stack[ps.tos] != ifhead)
154	    diag2(1, "Unmatched 'else'");
155	else {
156	    ps.ind_level = ps.il[ps.tos];	/* indentation for else should
157						 * be same as for if */
158	    ps.i_l_follow = ps.ind_level + 1;	/* everything following should
159						 * be in 1 level */
160	    ps.p_stack[ps.tos] = elsehead;
161	    /* remember if with else */
162	    ps.search_brace = btype_2 | ps.else_if;
163	}
164	break;
165
166    case rbrace:		/* scanned a } */
167	/* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
168	if (ps.p_stack[ps.tos - 1] == lbrace) {
169	    ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
170	    ps.p_stack[ps.tos] = stmt;
171	}
172	else
173	    diag2(1, "Statement nesting error");
174	break;
175
176    case swstmt:		/* had switch (...) */
177	ps.p_stack[++ps.tos] = swstmt;
178	ps.cstk[ps.tos] = case_ind;
179	/* save current case indent level */
180	ps.il[ps.tos] = ps.i_l_follow;
181	case_ind = ps.i_l_follow + ps.case_indent;	/* cases should be one
182							 * level down from
183							 * switch */
184	ps.i_l_follow += ps.case_indent + 1;	/* statements should be two
185						 * levels in */
186	ps.search_brace = btype_2;
187	break;
188
189    case semicolon:		/* this indicates a simple stmt */
190	break_comma = false;	/* turn off flag to break after commas in a
191				 * declaration */
192	ps.p_stack[++ps.tos] = stmt;
193	ps.il[ps.tos] = ps.ind_level;
194	break;
195
196    default:			/* this is an error */
197	diag2(1, "Unknown code to parser");
198	return;
199
200
201    }				/* end of switch */
202
203    reduce();			/* see if any reduction can be done */
204
205#ifdef debug
206    for (i = 1; i <= ps.tos; ++i)
207	printf("(%d %d)", ps.p_stack[i], ps.il[i]);
208    printf("\n");
209#endif
210
211    return;
212}
213
214/*
215 * NAME: reduce
216 *
217 * FUNCTION: Implements the reduce part of the parsing algorithm
218 *
219 * ALGORITHM: The following reductions are done.  Reductions are repeated
220 *	until no more are possible.
221 *
222 * Old TOS		New TOS
223 * <stmt> <stmt>	<stmtl>
224 * <stmtl> <stmt>	<stmtl>
225 * do <stmt>		"dostmt"
226 * if <stmt>		"ifstmt"
227 * switch <stmt>	<stmt>
228 * decl <stmt>		<stmt>
229 * "ifelse" <stmt>	<stmt>
230 * for <stmt>		<stmt>
231 * while <stmt>		<stmt>
232 * "dostmt" while	<stmt>
233 *
234 * On each reduction, ps.i_l_follow (the indentation for the following line)
235 * is set to the indentation level associated with the old TOS.
236 *
237 * PARAMETERS: None
238 *
239 * RETURNS: Nothing
240 *
241 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
242 *
243 * CALLS: None
244 *
245 * CALLED BY: parse
246 *
247 * HISTORY: initial coding 	November 1976	D A Willcox of CAC
248 *
249 */
250/*----------------------------------------------*\
251|   REDUCTION PHASE				    |
252\*----------------------------------------------*/
253static void
254reduce(void)
255{
256    int i;
257
258    for (;;) {			/* keep looping until there is nothing left to
259				 * reduce */
260
261	switch (ps.p_stack[ps.tos]) {
262
263	case stmt:
264	    switch (ps.p_stack[ps.tos - 1]) {
265
266	    case stmt:
267	    case stmtl:
268		/* stmtl stmt or stmt stmt */
269		ps.p_stack[--ps.tos] = stmtl;
270		break;
271
272	    case dolit:	/* <do> <stmt> */
273		ps.p_stack[--ps.tos] = dohead;
274		ps.i_l_follow = ps.il[ps.tos];
275		break;
276
277	    case ifstmt:
278		/* <if> <stmt> */
279		ps.p_stack[--ps.tos] = ifhead;
280		for (i = ps.tos - 1;
281			(
282			 ps.p_stack[i] != stmt
283			 &&
284			 ps.p_stack[i] != stmtl
285			 &&
286			 ps.p_stack[i] != lbrace
287			 );
288			--i);
289		ps.i_l_follow = ps.il[i];
290		/*
291		 * for the time being, we will assume that there is no else on
292		 * this if, and set the indentation level accordingly. If an
293		 * else is scanned, it will be fixed up later
294		 */
295		break;
296
297	    case swstmt:
298		/* <switch> <stmt> */
299		case_ind = ps.cstk[ps.tos - 1];
300
301	    case decl:		/* finish of a declaration */
302	    case elsehead:
303		/* <<if> <stmt> else> <stmt> */
304	    case forstmt:
305		/* <for> <stmt> */
306	    case whilestmt:
307		/* <while> <stmt> */
308		ps.p_stack[--ps.tos] = stmt;
309		ps.i_l_follow = ps.il[ps.tos];
310		break;
311
312	    default:		/* <anything else> <stmt> */
313		return;
314
315	    }			/* end of section for <stmt> on top of stack */
316	    break;
317
318	case whilestmt:	/* while (...) on top */
319	    if (ps.p_stack[ps.tos - 1] == dohead) {
320		/* it is termination of a do while */
321		ps.tos -= 2;
322		break;
323	    }
324	    else
325		return;
326
327	default:		/* anything else on top */
328	    return;
329
330	}
331    }
332}
333