2 * SPDX-License-Identifier: BSD-4-Clause
4 * Copyright (c) 1985 Sun Microsystems, Inc.
5 * Copyright (c) 1980, 1993
6 * The Regents of the University of California. All rights reserved.
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10 * modification, are permitted provided that the following conditions
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
40 static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93";
44 #include <sys/cdefs.h>
45 __FBSDID("$FreeBSD$");
49 #include "indent_globs.h"
50 #include "indent_codes.h"
53 static void reduce(void);
56 parse(int tk) /* tk: the code for the construct scanned */
61 printf("%2d - %s\n", tk, token);
64 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
65 /* true if we have an if without an else */
66 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt
68 reduce(); /* see if this allows any reduction */
72 switch (tk) { /* go on and figure out what to do with the
75 case decl: /* scanned a declaration word */
76 ps.search_brace = opt.btype_2;
77 /* indicate that following brace should be on same line */
78 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration
80 break_comma = true; /* while in declaration, newline should be
81 * forced after comma */
82 ps.p_stack[++ps.tos] = decl;
83 ps.il[ps.tos] = ps.i_l_follow;
85 if (opt.ljust_decl) {/* only do if we want left justified
88 for (i = ps.tos - 1; i > 0; --i)
89 if (ps.p_stack[i] == decl)
90 ++ps.ind_level; /* indentation is number of
91 * declaration levels deep we are */
92 ps.i_l_follow = ps.ind_level;
97 case ifstmt: /* scanned if (...) */
98 if (ps.p_stack[ps.tos] == elsehead && opt.else_if) /* "else if ..." */
100 * Note that the stack pointer here is decremented, effectively
101 * reducing "else if" to "if". This saves a lot of stack space
102 * in case of a long "if-else-if ... else-if" sequence.
104 ps.i_l_follow = ps.il[ps.tos--];
105 /* the rest is the same as for dolit and forstmt */
106 case dolit: /* 'do' */
107 case forstmt: /* for (...) */
108 ps.p_stack[++ps.tos] = tk;
109 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
110 ++ps.i_l_follow; /* subsequent statements should be indented 1 */
111 ps.search_brace = opt.btype_2;
114 case lbrace: /* scanned { */
115 break_comma = false; /* don't break comma in an initial list */
116 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
117 || ps.p_stack[ps.tos] == stmtl)
118 ++ps.i_l_follow; /* it is a random, isolated stmt group or a
121 if (s_code == e_code) {
123 * only do this if there is nothing on the line
127 * it is a group as part of a while, for, etc.
129 if (ps.p_stack[ps.tos] == swstmt && opt.case_indent >= 1)
132 * for a switch, brace should be two levels out from the code
137 ps.p_stack[++ps.tos] = lbrace;
138 ps.il[ps.tos] = ps.ind_level;
139 ps.p_stack[++ps.tos] = stmt;
140 /* allow null stmt between braces */
141 ps.il[ps.tos] = ps.i_l_follow;
144 case whilestmt: /* scanned while (...) */
145 if (ps.p_stack[ps.tos] == dohead) {
146 /* it is matched with do stmt */
147 ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
148 ps.p_stack[++ps.tos] = whilestmt;
149 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
151 else { /* it is a while loop */
152 ps.p_stack[++ps.tos] = whilestmt;
153 ps.il[ps.tos] = ps.i_l_follow;
155 ps.search_brace = opt.btype_2;
160 case elselit: /* scanned an else */
162 if (ps.p_stack[ps.tos] != ifhead)
163 diag2(1, "Unmatched 'else'");
165 ps.ind_level = ps.il[ps.tos]; /* indentation for else should
166 * be same as for if */
167 ps.i_l_follow = ps.ind_level + 1; /* everything following should
169 ps.p_stack[ps.tos] = elsehead;
170 /* remember if with else */
171 ps.search_brace = opt.btype_2 | opt.else_if;
175 case rbrace: /* scanned a } */
176 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
177 if (ps.tos > 0 && ps.p_stack[ps.tos - 1] == lbrace) {
178 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
179 ps.p_stack[ps.tos] = stmt;
182 diag2(1, "Statement nesting error");
185 case swstmt: /* had switch (...) */
186 ps.p_stack[++ps.tos] = swstmt;
187 ps.cstk[ps.tos] = case_ind;
188 /* save current case indent level */
189 ps.il[ps.tos] = ps.i_l_follow;
190 case_ind = ps.i_l_follow + opt.case_indent; /* cases should be one
193 ps.i_l_follow += opt.case_indent + 1; /* statements should be two
195 ps.search_brace = opt.btype_2;
198 case semicolon: /* this indicates a simple stmt */
199 break_comma = false; /* turn off flag to break after commas in a
201 ps.p_stack[++ps.tos] = stmt;
202 ps.il[ps.tos] = ps.ind_level;
205 default: /* this is an error */
206 diag2(1, "Unknown code to parser");
210 } /* end of switch */
212 if (ps.tos >= STACKSIZE - 1)
213 errx(1, "Parser stack overflow");
215 reduce(); /* see if any reduction can be done */
218 for (i = 1; i <= ps.tos; ++i)
219 printf("(%d %d)", ps.p_stack[i], ps.il[i]);
229 * FUNCTION: Implements the reduce part of the parsing algorithm
231 * ALGORITHM: The following reductions are done. Reductions are repeated
232 * until no more are possible.
235 * <stmt> <stmt> <stmtl>
236 * <stmtl> <stmt> <stmtl>
239 * switch <stmt> <stmt>
241 * "ifelse" <stmt> <stmt>
243 * while <stmt> <stmt>
244 * "dostmt" while <stmt>
246 * On each reduction, ps.i_l_follow (the indentation for the following line)
247 * is set to the indentation level associated with the old TOS.
253 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
259 * HISTORY: initial coding November 1976 D A Willcox of CAC
262 /*----------------------------------------------*\
264 \*----------------------------------------------*/
270 for (;;) { /* keep looping until there is nothing left to
273 switch (ps.p_stack[ps.tos]) {
276 switch (ps.p_stack[ps.tos - 1]) {
280 /* stmtl stmt or stmt stmt */
281 ps.p_stack[--ps.tos] = stmtl;
284 case dolit: /* <do> <stmt> */
285 ps.p_stack[--ps.tos] = dohead;
286 ps.i_l_follow = ps.il[ps.tos];
291 ps.p_stack[--ps.tos] = ifhead;
294 ps.p_stack[i] != stmt
296 ps.p_stack[i] != stmtl
298 ps.p_stack[i] != lbrace
301 ps.i_l_follow = ps.il[i];
303 * for the time being, we will assume that there is no else on
304 * this if, and set the indentation level accordingly. If an
305 * else is scanned, it will be fixed up later
310 /* <switch> <stmt> */
311 case_ind = ps.cstk[ps.tos - 1];
313 case decl: /* finish of a declaration */
315 /* <<if> <stmt> else> <stmt> */
320 ps.p_stack[--ps.tos] = stmt;
321 ps.i_l_follow = ps.il[ps.tos];
324 default: /* <anything else> <stmt> */
327 } /* end of section for <stmt> on top of stack */
330 case whilestmt: /* while (...) on top */
331 if (ps.p_stack[ps.tos - 1] == dohead) {
332 /* it is termination of a do while */
339 default: /* anything else on top */