parse.c revision 1.8
1 /* $NetBSD: parse.c,v 1.8 2019/02/03 03:19:29 mrg Exp $ */ 2 3 /* 4 * Copyright (c) 1980, 1993 5 * The Regents of the University of California. 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 /* 33 * Copyright (c) 1976 Board of Trustees of the University of Illinois. 34 * Copyright (c) 1985 Sun Microsystems, Inc. 35 * All rights reserved. 36 * 37 * Redistribution and use in source and binary forms, with or without 38 * modification, are permitted provided that the following conditions 39 * are met: 40 * 1. Redistributions of source code must retain the above copyright 41 * notice, this list of conditions and the following disclaimer. 42 * 2. Redistributions in binary form must reproduce the above copyright 43 * notice, this list of conditions and the following disclaimer in the 44 * documentation and/or other materials provided with the distribution. 45 * 3. All advertising materials mentioning features or use of this software 46 * must display the following acknowledgement: 47 * This product includes software developed by the University of 48 * California, Berkeley and its contributors. 49 * 4. Neither the name of the University nor the names of its contributors 50 * may be used to endorse or promote products derived from this software 51 * without specific prior written permission. 52 * 53 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 54 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 55 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 56 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 57 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 58 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 59 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 60 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 61 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 62 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 63 * SUCH DAMAGE. 64 */ 65 66 #include <sys/cdefs.h> 67 #ifndef lint 68 #if 0 69 static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93"; 70 #else 71 __RCSID("$NetBSD: parse.c,v 1.8 2019/02/03 03:19:29 mrg Exp $"); 72 #endif 73 #endif /* not lint */ 74 75 #include <stdio.h> 76 #include "indent_globs.h" 77 #include "indent_codes.h" 78 79 /* tk: the code for the construct scanned */ 80 void 81 parse(int tk) 82 { 83 int i; 84 85 #ifdef debug 86 printf("%2d - %s\n", tk, token); 87 #endif 88 89 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 90 /* true if we have an if without an else */ 91 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= 92 * stmt reduction */ 93 reduce(); /* see if this allows any reduction */ 94 } 95 96 97 switch (tk) { /* go on and figure out what to do with the 98 * input */ 99 100 case decl: /* scanned a declaration word */ 101 ps.search_brace = btype_2; 102 /* indicate that following brace should be on same line */ 103 if (ps.p_stack[ps.tos] != decl) { /* only put one 104 * declaration onto 105 * stack */ 106 break_comma = true; /* while in declaration, 107 * newline should be forced 108 * after comma */ 109 ps.p_stack[++ps.tos] = decl; 110 ps.il[ps.tos] = ps.i_l_follow; 111 112 if (ps.ljust_decl) { /* only do if we want left 113 * justified declarations */ 114 ps.ind_level = 0; 115 for (i = ps.tos - 1; i > 0; --i) 116 if (ps.p_stack[i] == decl) 117 ++ps.ind_level; /* indentation is number 118 * of declaration levels 119 * deep we are */ 120 ps.i_l_follow = ps.ind_level; 121 } 122 } 123 break; 124 125 case ifstmt: /* scanned if (...) */ 126 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 127 ps.i_l_follow = ps.il[ps.tos]; 128 /* FALLTHROUGH */ 129 case dolit: /* 'do' */ 130 case forstmt: /* for (...) */ 131 ps.p_stack[++ps.tos] = tk; 132 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 133 ++ps.i_l_follow;/* subsequent statements should be indented 1 */ 134 ps.search_brace = btype_2; 135 break; 136 137 case lbrace: /* scanned { */ 138 break_comma = false; /* don't break comma in an initial 139 * list */ 140 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 141 || ps.p_stack[ps.tos] == stmtl) 142 ++ps.i_l_follow; /* it is a random, isolated 143 * stmt group or a declaration */ 144 else { 145 if (s_code == e_code) { 146 /* 147 * only do this if there is nothing on the line 148 */ 149 --ps.ind_level; 150 /* 151 * it is a group as part of a while, for, etc. 152 */ 153 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 154 --ps.ind_level; 155 /* 156 * for a switch, brace should be two levels out from the code 157 */ 158 } 159 } 160 161 ps.p_stack[++ps.tos] = lbrace; 162 ps.il[ps.tos] = ps.ind_level; 163 ps.p_stack[++ps.tos] = stmt; 164 /* allow null stmt between braces */ 165 ps.il[ps.tos] = ps.i_l_follow; 166 break; 167 168 case whilestmt: /* scanned while (...) */ 169 if (ps.p_stack[ps.tos] == dohead) { 170 /* it is matched with do stmt */ 171 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 172 ps.p_stack[++ps.tos] = whilestmt; 173 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 174 } else { /* it is a while loop */ 175 ps.p_stack[++ps.tos] = whilestmt; 176 ps.il[ps.tos] = ps.i_l_follow; 177 ++ps.i_l_follow; 178 ps.search_brace = btype_2; 179 } 180 181 break; 182 183 case elselit: /* scanned an else */ 184 185 if (ps.p_stack[ps.tos] != ifhead) 186 diag(1, "Unmatched 'else'"); 187 else { 188 ps.ind_level = ps.il[ps.tos]; /* indentation for else 189 * should be same as for 190 * if */ 191 ps.i_l_follow = ps.ind_level + 1; /* everything following 192 * should be in 1 level */ 193 ps.p_stack[ps.tos] = elsehead; 194 /* remember if with else */ 195 ps.search_brace = btype_2 | ps.else_if; 196 } 197 break; 198 199 case rbrace: /* scanned a } */ 200 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 201 if (ps.p_stack[ps.tos - 1] == lbrace) { 202 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 203 ps.p_stack[ps.tos] = stmt; 204 } else 205 diag(1, "Stmt nesting error."); 206 break; 207 208 case swstmt: /* had switch (...) */ 209 ps.p_stack[++ps.tos] = swstmt; 210 ps.cstk[ps.tos] = case_ind; 211 /* save current case indent level */ 212 ps.il[ps.tos] = ps.i_l_follow; 213 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 214 * level down from 215 * switch */ 216 ps.i_l_follow += ps.case_indent + 1; /* statements should be 217 * two levels in */ 218 ps.search_brace = btype_2; 219 break; 220 221 case semicolon: /* this indicates a simple stmt */ 222 break_comma = false; /* turn off flag to break after commas 223 * in a declaration */ 224 ps.p_stack[++ps.tos] = stmt; 225 ps.il[ps.tos] = ps.ind_level; 226 break; 227 228 default: /* this is an error */ 229 diag(1, "Unknown code to parser"); 230 return; 231 232 233 } /* end of switch */ 234 235 reduce(); /* see if any reduction can be done */ 236 237 #ifdef debug 238 for (i = 1; i <= ps.tos; ++i) 239 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 240 printf("\n"); 241 #endif 242 } 243 /* 244 * NAME: reduce 245 * 246 * FUNCTION: Implements the reduce part of the parsing algorithm 247 * 248 * ALGORITHM: The following reductions are done. Reductions are repeated 249 * until no more are possible. 250 * 251 * Old TOS New TOS 252 * <stmt> <stmt> <stmtl> 253 * <stmtl> <stmt> <stmtl> 254 * do <stmt> "dostmt" 255 * if <stmt> "ifstmt" 256 * switch <stmt> <stmt> 257 * decl <stmt> <stmt> 258 * "ifelse" <stmt> <stmt> 259 * for <stmt> <stmt> 260 * while <stmt> <stmt> 261 * "dostmt" while <stmt> 262 * 263 * On each reduction, ps.i_l_follow (the indentation for the following line) 264 * is set to the indentation level associated with the old TOS. 265 * 266 * PARAMETERS: None 267 * 268 * RETURNS: Nothing 269 * 270 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 271 * 272 * CALLS: None 273 * 274 * CALLED BY: parse 275 * 276 * HISTORY: initial coding November 1976 D A Willcox of CAC 277 * 278 */ 279 /*----------------------------------------------*\ 280 | REDUCTION PHASE | 281 \*----------------------------------------------*/ 282 void 283 reduce(void) 284 { 285 286 int i; 287 288 for (;;) { /* keep looping until there is nothing left to 289 * reduce */ 290 291 switch (ps.p_stack[ps.tos]) { 292 293 case stmt: 294 switch (ps.p_stack[ps.tos - 1]) { 295 296 case stmt: 297 case stmtl: 298 /* stmtl stmt or stmt stmt */ 299 ps.p_stack[--ps.tos] = stmtl; 300 break; 301 302 case dolit: /* <do> <stmt> */ 303 ps.p_stack[--ps.tos] = dohead; 304 ps.i_l_follow = ps.il[ps.tos]; 305 break; 306 307 case ifstmt: 308 /* <if> <stmt> */ 309 ps.p_stack[--ps.tos] = ifhead; 310 for (i = ps.tos - 1; 311 ( 312 ps.p_stack[i] != stmt 313 && 314 ps.p_stack[i] != stmtl 315 && 316 ps.p_stack[i] != lbrace 317 ); 318 --i); 319 ps.i_l_follow = ps.il[i]; 320 /* 321 * for the time being, we will assume that there is no else on 322 * this if, and set the indentation level accordingly. If an 323 * else is scanned, it will be fixed up later 324 */ 325 break; 326 327 case swstmt: 328 /* <switch> <stmt> */ 329 case_ind = ps.cstk[ps.tos - 1]; 330 331 /* FALLTHROUGH */ 332 case decl: /* finish of a declaration */ 333 case elsehead: 334 /* <<if> <stmt> else> <stmt> */ 335 case forstmt: 336 /* <for> <stmt> */ 337 case whilestmt: 338 /* <while> <stmt> */ 339 ps.p_stack[--ps.tos] = stmt; 340 ps.i_l_follow = ps.il[ps.tos]; 341 break; 342 343 default: /* <anything else> <stmt> */ 344 return; 345 346 } /* end of section for <stmt> on top of stack */ 347 break; 348 349 case whilestmt:/* while (...) on top */ 350 if (ps.p_stack[ps.tos - 1] == dohead) { 351 /* it is termination of a do while */ 352 ps.p_stack[--ps.tos] = stmt; 353 break; 354 } else 355 return; 356 357 default: /* anything else on top */ 358 return; 359 360 } 361 } 362 } 363
Indexes created Tue Sep 30 20:09:53 GMT 2025