Line data Source code
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. Neither the name of the University nor the names of its contributors
16 : * may be used to endorse or promote products derived from this software
17 : * without specific prior written permission.
18 : *
19 : * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20 : * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 : * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 : * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23 : * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24 : * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25 : * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26 : * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27 : * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28 : * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29 : * SUCH DAMAGE.
30 : */
31 :
32 : #if 0
33 : #ifndef lint
34 : static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93";
35 : #endif /* not lint */
36 : #endif
37 :
38 : #include "c.h"
39 :
40 : #include <err.h>
41 : #include <stdio.h>
42 : #include "indent_globs.h"
43 : #include "indent_codes.h"
44 : #include "indent.h"
45 :
46 : static void reduce(void);
47 :
48 : void
49 0 : parse(int tk) /* tk: the code for the construct scanned */
50 : {
51 0 : int i;
52 :
53 : #ifdef debug
54 : printf("%2d - %s\n", tk, token);
55 : #endif
56 :
57 0 : while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
58 : /* true if we have an if without an else */
59 0 : ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt
60 : * reduction */
61 0 : reduce(); /* see if this allows any reduction */
62 : }
63 :
64 :
65 0 : switch (tk) { /* go on and figure out what to do with the
66 : * input */
67 :
68 : case decl: /* scanned a declaration word */
69 0 : ps.search_brace = btype_2;
70 : /* indicate that following brace should be on same line */
71 0 : if (ps.p_stack[ps.tos] != decl) { /* only put one declaration
72 : * onto stack */
73 0 : break_comma = true; /* while in declaration, newline should be
74 : * forced after comma */
75 0 : ps.p_stack[++ps.tos] = decl;
76 0 : ps.il[ps.tos] = ps.i_l_follow;
77 :
78 0 : if (ps.ljust_decl) {/* only do if we want left justified
79 : * declarations */
80 0 : ps.ind_level = 0;
81 0 : for (i = ps.tos - 1; i > 0; --i)
82 0 : if (ps.p_stack[i] == decl)
83 0 : ++ps.ind_level; /* indentation is number of
84 : * declaration levels deep we are */
85 0 : ps.i_l_follow = ps.ind_level;
86 0 : }
87 0 : }
88 0 : break;
89 :
90 : case ifstmt: /* scanned if (...) */
91 0 : if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */
92 : /*
93 : * Note that the stack pointer here is decremented, effectively
94 : * reducing "else if" to "if". This saves a lot of stack space
95 : * in case of a long "if-else-if ... else-if" sequence.
96 : */
97 0 : ps.i_l_follow = ps.il[ps.tos--];
98 : /* the rest is the same as for dolit and forstmt */
99 : /* FALLTHROUGH */
100 : case dolit: /* 'do' */
101 : case forstmt: /* for (...) */
102 0 : ps.p_stack[++ps.tos] = tk;
103 0 : ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
104 0 : ++ps.i_l_follow; /* subsequent statements should be indented 1 */
105 0 : ps.search_brace = btype_2;
106 0 : break;
107 :
108 : case lbrace: /* scanned { */
109 0 : break_comma = false; /* don't break comma in an initial list */
110 0 : if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
111 0 : || ps.p_stack[ps.tos] == stmtl)
112 0 : ++ps.i_l_follow; /* it is a random, isolated stmt group or a
113 : * declaration */
114 : else {
115 0 : if (s_code == e_code) {
116 : /*
117 : * only do this if there is nothing on the line
118 : */
119 0 : --ps.ind_level;
120 : /*
121 : * it is a group as part of a while, for, etc.
122 : */
123 0 : if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
124 0 : --ps.ind_level;
125 : /*
126 : * for a switch, brace should be two levels out from the code
127 : */
128 0 : }
129 : }
130 :
131 0 : ps.p_stack[++ps.tos] = lbrace;
132 0 : ps.il[ps.tos] = ps.ind_level;
133 0 : ps.p_stack[++ps.tos] = stmt;
134 : /* allow null stmt between braces */
135 0 : ps.il[ps.tos] = ps.i_l_follow;
136 0 : break;
137 :
138 : case whilestmt: /* scanned while (...) */
139 0 : if (ps.p_stack[ps.tos] == dohead) {
140 : /* it is matched with do stmt */
141 0 : ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
142 0 : ps.p_stack[++ps.tos] = whilestmt;
143 0 : ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
144 0 : }
145 : else { /* it is a while loop */
146 0 : ps.p_stack[++ps.tos] = whilestmt;
147 0 : ps.il[ps.tos] = ps.i_l_follow;
148 0 : ++ps.i_l_follow;
149 0 : ps.search_brace = btype_2;
150 : }
151 :
152 0 : break;
153 :
154 : case elselit: /* scanned an else */
155 :
156 0 : if (ps.p_stack[ps.tos] != ifhead)
157 0 : diag2(1, "Unmatched 'else'");
158 : else {
159 0 : ps.ind_level = ps.il[ps.tos]; /* indentation for else should
160 : * be same as for if */
161 0 : ps.i_l_follow = ps.ind_level + 1; /* everything following should
162 : * be in 1 level */
163 0 : ps.p_stack[ps.tos] = elsehead;
164 : /* remember if with else */
165 0 : ps.search_brace = btype_2 | ps.else_if;
166 : }
167 0 : break;
168 :
169 : case rbrace: /* scanned a } */
170 : /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
171 0 : if (ps.tos > 0 && ps.p_stack[ps.tos - 1] == lbrace) {
172 0 : ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
173 0 : ps.p_stack[ps.tos] = stmt;
174 0 : }
175 : else
176 0 : diag2(1, "Statement nesting error");
177 0 : break;
178 :
179 : case swstmt: /* had switch (...) */
180 0 : ps.p_stack[++ps.tos] = swstmt;
181 0 : ps.cstk[ps.tos] = case_ind;
182 : /* save current case indent level */
183 0 : ps.il[ps.tos] = ps.i_l_follow;
184 0 : case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one
185 : * level down from
186 : * switch */
187 0 : ps.i_l_follow += ps.case_indent + 1; /* statements should be two
188 : * levels in */
189 0 : ps.search_brace = btype_2;
190 0 : break;
191 :
192 : case semicolon: /* this indicates a simple stmt */
193 0 : break_comma = false; /* turn off flag to break after commas in a
194 : * declaration */
195 0 : ps.p_stack[++ps.tos] = stmt;
196 0 : ps.il[ps.tos] = ps.ind_level;
197 0 : break;
198 :
199 : default: /* this is an error */
200 0 : diag2(1, "Unknown code to parser");
201 0 : return;
202 :
203 :
204 : } /* end of switch */
205 :
206 0 : if (ps.tos >= nitems(ps.p_stack) - 1)
207 0 : errx(1, "Parser stack overflow");
208 :
209 0 : reduce(); /* see if any reduction can be done */
210 :
211 : #ifdef debug
212 : for (i = 1; i <= ps.tos; ++i)
213 : printf("(%d %d)", ps.p_stack[i], ps.il[i]);
214 : printf("\n");
215 : #endif
216 :
217 0 : return;
218 0 : }
219 :
220 : /*
221 : * NAME: reduce
222 : *
223 : * FUNCTION: Implements the reduce part of the parsing algorithm
224 : *
225 : * ALGORITHM: The following reductions are done. Reductions are repeated
226 : * until no more are possible.
227 : *
228 : * Old TOS New TOS
229 : * <stmt> <stmt> <stmtl>
230 : * <stmtl> <stmt> <stmtl>
231 : * do <stmt> "dostmt"
232 : * if <stmt> "ifstmt"
233 : * switch <stmt> <stmt>
234 : * decl <stmt> <stmt>
235 : * "ifelse" <stmt> <stmt>
236 : * for <stmt> <stmt>
237 : * while <stmt> <stmt>
238 : * "dostmt" while <stmt>
239 : *
240 : * On each reduction, ps.i_l_follow (the indentation for the following line)
241 : * is set to the indentation level associated with the old TOS.
242 : *
243 : * PARAMETERS: None
244 : *
245 : * RETURNS: Nothing
246 : *
247 : * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
248 : *
249 : * CALLS: None
250 : *
251 : * CALLED BY: parse
252 : *
253 : * HISTORY: initial coding November 1976 D A Willcox of CAC
254 : *
255 : */
256 : /*----------------------------------------------*\
257 : | REDUCTION PHASE |
258 : \*----------------------------------------------*/
259 : static void
260 0 : reduce(void)
261 : {
262 0 : int i;
263 :
264 0 : for (;;) { /* keep looping until there is nothing left to
265 : * reduce */
266 :
267 0 : switch (ps.p_stack[ps.tos]) {
268 :
269 : case stmt:
270 0 : switch (ps.p_stack[ps.tos - 1]) {
271 :
272 : case stmt:
273 : case stmtl:
274 : /* stmtl stmt or stmt stmt */
275 0 : ps.p_stack[--ps.tos] = stmtl;
276 0 : break;
277 :
278 : case dolit: /* <do> <stmt> */
279 0 : ps.p_stack[--ps.tos] = dohead;
280 0 : ps.i_l_follow = ps.il[ps.tos];
281 0 : break;
282 :
283 : case ifstmt:
284 : /* <if> <stmt> */
285 0 : ps.p_stack[--ps.tos] = ifhead;
286 0 : for (i = ps.tos - 1;
287 : (
288 0 : ps.p_stack[i] != stmt
289 0 : &&
290 0 : ps.p_stack[i] != stmtl
291 0 : &&
292 0 : ps.p_stack[i] != lbrace
293 : );
294 0 : --i);
295 0 : ps.i_l_follow = ps.il[i];
296 : /*
297 : * for the time being, we will assume that there is no else on
298 : * this if, and set the indentation level accordingly. If an
299 : * else is scanned, it will be fixed up later
300 : */
301 0 : break;
302 :
303 : case swstmt:
304 : /* <switch> <stmt> */
305 0 : case_ind = ps.cstk[ps.tos - 1];
306 : /* FALLTHROUGH */
307 : case decl: /* finish of a declaration */
308 : case elsehead:
309 : /* <<if> <stmt> else> <stmt> */
310 : case forstmt:
311 : /* <for> <stmt> */
312 : case whilestmt:
313 : /* <while> <stmt> */
314 0 : ps.p_stack[--ps.tos] = stmt;
315 0 : ps.i_l_follow = ps.il[ps.tos];
316 0 : break;
317 :
318 : default: /* <anything else> <stmt> */
319 0 : return;
320 :
321 : } /* end of section for <stmt> on top of stack */
322 0 : break;
323 :
324 : case whilestmt: /* while (...) on top */
325 0 : if (ps.p_stack[ps.tos - 1] == dohead) {
326 : /* it is termination of a do while */
327 0 : ps.tos -= 2;
328 0 : break;
329 : }
330 : else
331 0 : return;
332 :
333 : default: /* anything else on top */
334 0 : return;
335 :
336 : }
337 : }
338 0 : }
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