1 /* $NetBSD: parse.c,v 1.10 2019/10/19 15:44:31 christos Exp $ */ 2 3 /*- 4 * SPDX-License-Identifier: BSD-4-Clause 5 * 6 * Copyright (c) 1985 Sun Microsystems, Inc. 7 * Copyright (c) 1980, 1993 8 * The Regents of the University of California. All rights reserved. 9 * All rights reserved. 10 * 11 * Redistribution and use in source and binary forms, with or without 12 * modification, are permitted provided that the following conditions 13 * are met: 14 * 1. Redistributions of source code must retain the above copyright 15 * notice, this list of conditions and the following disclaimer. 16 * 2. Redistributions in binary form must reproduce the above copyright 17 * notice, this list of conditions and the following disclaimer in the 18 * documentation and/or other materials provided with the distribution. 19 * 3. All advertising materials mentioning features or use of this software 20 * must display the following acknowledgement: 21 * This product includes software developed by the University of 22 * California, Berkeley and its contributors. 23 * 4. Neither the name of the University nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * 27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 37 * SUCH DAMAGE. 38 */ 39 40 #if 0 41 #ifndef lint 42 static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93"; 43 #endif /* not lint */ 44 #endif 45 46 #include <sys/cdefs.h> 47 #ifndef lint 48 #if defined(__NetBSD__) 49 __RCSID("$FreeBSD$"); 50 #else 51 __FBSDID("$FreeBSD: head/usr.bin/indent/parse.c 337651 2018-08-11 19:20:06Z pstef $"); 52 #endif 53 #endif 54 55 #include <err.h> 56 #include <stdio.h> 57 #include "indent_globs.h" 58 #include "indent_codes.h" 59 #include "indent.h" 60 61 static void reduce(void); 62 63 void 64 parse(int tk) /* tk: the code for the construct scanned */ 65 { 66 int i; 67 68 #ifdef debug 69 printf("%2d - %s\n", tk, token); 70 #endif 71 72 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 73 /* true if we have an if without an else */ 74 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 75 * reduction */ 76 reduce(); /* see if this allows any reduction */ 77 } 78 79 80 switch (tk) { /* go on and figure out what to do with the 81 * input */ 82 83 case decl: /* scanned a declaration word */ 84 ps.search_brace = opt.btype_2; 85 /* indicate that following brace should be on same line */ 86 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 87 * onto stack */ 88 break_comma = true; /* while in declaration, newline should be 89 * forced after comma */ 90 ps.p_stack[++ps.tos] = decl; 91 ps.il[ps.tos] = ps.i_l_follow; 92 93 if (opt.ljust_decl) {/* only do if we want left justified 94 * declarations */ 95 ps.ind_level = 0; 96 for (i = ps.tos - 1; i > 0; --i) 97 if (ps.p_stack[i] == decl) 98 ++ps.ind_level; /* indentation is number of 99 * declaration levels deep we are */ 100 ps.i_l_follow = ps.ind_level; 101 } 102 } 103 break; 104 105 case ifstmt: /* scanned if (...) */ 106 if (ps.p_stack[ps.tos] == elsehead && opt.else_if) /* "else if ..." */ 107 /* 108 * Note that the stack pointer here is decremented, effectively 109 * reducing "else if" to "if". This saves a lot of stack space 110 * in case of a long "if-else-if ... else-if" sequence. 111 */ 112 ps.i_l_follow = ps.il[ps.tos--]; 113 /* the rest is the same as for dolit and forstmt */ 114 /* FALLTHROUGH */ 115 case dolit: /* 'do' */ 116 case forstmt: /* for (...) */ 117 ps.p_stack[++ps.tos] = tk; 118 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 119 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 120 ps.search_brace = opt.btype_2; 121 break; 122 123 case lbrace: /* scanned { */ 124 break_comma = false; /* don't break comma in an initial list */ 125 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 126 || ps.p_stack[ps.tos] == stmtl) 127 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 128 * declaration */ 129 else { 130 if (s_code == e_code) { 131 /* 132 * only do this if there is nothing on the line 133 */ 134 --ps.ind_level; 135 /* 136 * it is a group as part of a while, for, etc. 137 */ 138 if (ps.p_stack[ps.tos] == swstmt && opt.case_indent >= 1) 139 --ps.ind_level; 140 /* 141 * for a switch, brace should be two levels out from the code 142 */ 143 } 144 } 145 146 ps.p_stack[++ps.tos] = lbrace; 147 ps.il[ps.tos] = ps.ind_level; 148 ps.p_stack[++ps.tos] = stmt; 149 /* allow null stmt between braces */ 150 ps.il[ps.tos] = ps.i_l_follow; 151 break; 152 153 case whilestmt: /* scanned while (...) */ 154 if (ps.p_stack[ps.tos] == dohead) { 155 /* it is matched with do stmt */ 156 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 157 ps.p_stack[++ps.tos] = whilestmt; 158 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 159 } 160 else { /* it is a while loop */ 161 ps.p_stack[++ps.tos] = whilestmt; 162 ps.il[ps.tos] = ps.i_l_follow; 163 ++ps.i_l_follow; 164 ps.search_brace = opt.btype_2; 165 } 166 167 break; 168 169 case elselit: /* scanned an else */ 170 171 if (ps.p_stack[ps.tos] != ifhead) 172 diag(1, "Unmatched 'else'"); 173 else { 174 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 175 * be same as for if */ 176 ps.i_l_follow = ps.ind_level + 1; /* everything following should 177 * be in 1 level */ 178 ps.p_stack[ps.tos] = elsehead; 179 /* remember if with else */ 180 ps.search_brace = opt.btype_2 | opt.else_if; 181 } 182 break; 183 184 case rbrace: /* scanned a } */ 185 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 186 if (ps.tos > 0 && ps.p_stack[ps.tos - 1] == lbrace) { 187 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 188 ps.p_stack[ps.tos] = stmt; 189 } 190 else 191 diag(1, "Statement nesting error"); 192 break; 193 194 case swstmt: /* had switch (...) */ 195 ps.p_stack[++ps.tos] = swstmt; 196 ps.cstk[ps.tos] = case_ind; 197 /* save current case indent level */ 198 ps.il[ps.tos] = ps.i_l_follow; 199 case_ind = ps.i_l_follow + opt.case_indent; /* cases should be one 200 * level down from 201 * switch */ 202 ps.i_l_follow += opt.case_indent + 1; /* statements should be two 203 * levels in */ 204 ps.search_brace = opt.btype_2; 205 break; 206 207 case semicolon: /* this indicates a simple stmt */ 208 break_comma = false; /* turn off flag to break after commas in a 209 * declaration */ 210 ps.p_stack[++ps.tos] = stmt; 211 ps.il[ps.tos] = ps.ind_level; 212 break; 213 214 default: /* this is an error */ 215 diag(1, "Unknown code to parser"); 216 return; 217 218 219 } /* end of switch */ 220 221 if (ps.tos >= STACKSIZE - 1) 222 errx(1, "Parser stack overflow"); 223 224 reduce(); /* see if any reduction can be done */ 225 226 #ifdef debug 227 for (i = 1; i <= ps.tos; ++i) 228 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 229 printf("\n"); 230 #endif 231 232 return; 233 } 234 235 /* 236 * NAME: reduce 237 * 238 * FUNCTION: Implements the reduce part of the parsing algorithm 239 * 240 * ALGORITHM: The following reductions are done. Reductions are repeated 241 * until no more are possible. 242 * 243 * Old TOS New TOS 244 * <stmt> <stmt> <stmtl> 245 * <stmtl> <stmt> <stmtl> 246 * do <stmt> "dostmt" 247 * if <stmt> "ifstmt" 248 * switch <stmt> <stmt> 249 * decl <stmt> <stmt> 250 * "ifelse" <stmt> <stmt> 251 * for <stmt> <stmt> 252 * while <stmt> <stmt> 253 * "dostmt" while <stmt> 254 * 255 * On each reduction, ps.i_l_follow (the indentation for the following line) 256 * is set to the indentation level associated with the old TOS. 257 * 258 * PARAMETERS: None 259 * 260 * RETURNS: Nothing 261 * 262 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 263 * 264 * CALLS: None 265 * 266 * CALLED BY: parse 267 * 268 * HISTORY: initial coding November 1976 D A Willcox of CAC 269 * 270 */ 271 /*----------------------------------------------*\ 272 | REDUCTION PHASE | 273 \*----------------------------------------------*/ 274 static void 275 reduce(void) 276 { 277 int i; 278 279 for (;;) { /* keep looping until there is nothing left to 280 * reduce */ 281 282 switch (ps.p_stack[ps.tos]) { 283 284 case stmt: 285 switch (ps.p_stack[ps.tos - 1]) { 286 287 case stmt: 288 case stmtl: 289 /* stmtl stmt or stmt stmt */ 290 ps.p_stack[--ps.tos] = stmtl; 291 break; 292 293 case dolit: /* <do> <stmt> */ 294 ps.p_stack[--ps.tos] = dohead; 295 ps.i_l_follow = ps.il[ps.tos]; 296 break; 297 298 case ifstmt: 299 /* <if> <stmt> */ 300 ps.p_stack[--ps.tos] = ifhead; 301 for (i = ps.tos - 1; 302 ( 303 ps.p_stack[i] != stmt 304 && 305 ps.p_stack[i] != stmtl 306 && 307 ps.p_stack[i] != lbrace 308 ); 309 --i); 310 ps.i_l_follow = ps.il[i]; 311 /* 312 * for the time being, we will assume that there is no else on 313 * this if, and set the indentation level accordingly. If an 314 * else is scanned, it will be fixed up later 315 */ 316 break; 317 318 case swstmt: 319 /* <switch> <stmt> */ 320 case_ind = ps.cstk[ps.tos - 1]; 321 /* FALLTHROUGH */ 322 case decl: /* finish of a declaration */ 323 case elsehead: 324 /* <<if> <stmt> else> <stmt> */ 325 case forstmt: 326 /* <for> <stmt> */ 327 case whilestmt: 328 /* <while> <stmt> */ 329 ps.p_stack[--ps.tos] = stmt; 330 ps.i_l_follow = ps.il[ps.tos]; 331 break; 332 333 default: /* <anything else> <stmt> */ 334 return; 335 336 } /* end of section for <stmt> on top of stack */ 337 break; 338 339 case whilestmt: /* while (...) on top */ 340 if (ps.p_stack[ps.tos - 1] == dohead) { 341 /* it is termination of a do while */ 342 ps.tos -= 2; 343 break; 344 } 345 else 346 return; 347 348 default: /* anything else on top */ 349 return; 350 351 } 352 } 353 } 354