1 /* $OpenBSD: parse.c,v 1.4 2001/01/08 07:14:42 pjanzen Exp $ */ 2 3 /* 4 * Copyright (c) 1980, 1993 5 * The Regents of the University of California. 6 * Copyright (c) 1976 Board of Trustees of the University of Illinois. 7 * Copyright (c) 1985 Sun Microsystems, Inc. 8 * All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef lint 40 /*static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93";*/ 41 static char rcsid[] = "$OpenBSD: parse.c,v 1.4 2001/01/08 07:14:42 pjanzen Exp $"; 42 #endif /* not lint */ 43 44 #include <stdio.h> 45 #include "indent_globs.h" 46 #include "indent_codes.h" 47 48 void reduce(); 49 50 void 51 parse(tk) 52 int tk; /* the code for the construct scanned */ 53 { 54 int i; 55 56 #ifdef debug 57 printf("%2d - %s\n", tk, token); 58 #endif 59 60 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 61 /* true if we have an if without an else */ 62 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 63 * reduction */ 64 reduce(); /* see if this allows any reduction */ 65 } 66 67 68 switch (tk) { /* go on and figure out what to do with the 69 * input */ 70 71 case decl: /* scanned a declaration word */ 72 ps.search_brace = btype_2; 73 /* indicate that following brace should be on same line */ 74 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 75 * onto stack */ 76 break_comma = true; /* while in declaration, newline should be 77 * forced after comma */ 78 ps.p_stack[++ps.tos] = decl; 79 ps.il[ps.tos] = ps.i_l_follow; 80 81 if (ps.ljust_decl) {/* only do if we want left justified 82 * declarations */ 83 ps.ind_level = 0; 84 for (i = ps.tos - 1; i > 0; --i) 85 if (ps.p_stack[i] == decl) 86 ++ps.ind_level; /* indentation is number of 87 * declaration levels deep we are */ 88 ps.i_l_follow = ps.ind_level; 89 } 90 } 91 break; 92 93 case ifstmt: /* scanned if (...) */ 94 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 95 ps.i_l_follow = ps.il[ps.tos]; 96 case dolit: /* 'do' */ 97 case forstmt: /* for (...) */ 98 ps.p_stack[++ps.tos] = tk; 99 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 100 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 101 ps.search_brace = btype_2; 102 break; 103 104 case lbrace: /* scanned { */ 105 break_comma = false; /* don't break comma in an initial list */ 106 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 107 || ps.p_stack[ps.tos] == stmtl) 108 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 109 * declaration */ 110 else { 111 if (s_code == e_code) { 112 /* 113 * only do this if there is nothing on the line 114 */ 115 --ps.ind_level; 116 /* 117 * it is a group as part of a while, for, etc. 118 */ 119 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 120 --ps.ind_level; 121 /* 122 * for a switch, brace should be two levels out from the code 123 */ 124 } 125 } 126 127 ps.p_stack[++ps.tos] = lbrace; 128 ps.il[ps.tos] = ps.ind_level; 129 ps.p_stack[++ps.tos] = stmt; 130 /* allow null stmt between braces */ 131 ps.il[ps.tos] = ps.i_l_follow; 132 break; 133 134 case whilestmt: /* scanned while (...) */ 135 if (ps.p_stack[ps.tos] == dohead) { 136 /* it is matched with do stmt */ 137 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 138 ps.p_stack[++ps.tos] = whilestmt; 139 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 140 } 141 else { /* it is a while loop */ 142 ps.p_stack[++ps.tos] = whilestmt; 143 ps.il[ps.tos] = ps.i_l_follow; 144 ++ps.i_l_follow; 145 ps.search_brace = btype_2; 146 } 147 148 break; 149 150 case elselit: /* scanned an else */ 151 152 if (ps.p_stack[ps.tos] != ifhead) 153 diag(1, "Unmatched 'else'"); 154 else { 155 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 156 * be same as for if */ 157 ps.i_l_follow = ps.ind_level + 1; /* everything following should 158 * be in 1 level */ 159 ps.p_stack[ps.tos] = elsehead; 160 /* remember if with else */ 161 ps.search_brace = btype_2 | ps.else_if; 162 } 163 break; 164 165 case rbrace: /* scanned a } */ 166 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 167 if (ps.p_stack[ps.tos - 1] == lbrace) { 168 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 169 ps.p_stack[ps.tos] = stmt; 170 } 171 else 172 diag(1, "Stmt nesting error."); 173 break; 174 175 case swstmt: /* had switch (...) */ 176 ps.p_stack[++ps.tos] = swstmt; 177 ps.cstk[ps.tos] = case_ind; 178 /* save current case indent level */ 179 ps.il[ps.tos] = ps.i_l_follow; 180 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 181 * level down from 182 * switch */ 183 ps.i_l_follow += ps.case_indent + 1; /* statements should be two 184 * levels in */ 185 ps.search_brace = btype_2; 186 break; 187 188 case semicolon: /* this indicates a simple stmt */ 189 break_comma = false; /* turn off flag to break after commas in a 190 * declaration */ 191 ps.p_stack[++ps.tos] = stmt; 192 ps.il[ps.tos] = ps.ind_level; 193 break; 194 195 default: /* this is an error */ 196 diag(1, "Unknown code to parser"); 197 return; 198 199 200 } /* end of switch */ 201 202 reduce(); /* see if any reduction can be done */ 203 204 #ifdef debug 205 for (i = 1; i <= ps.tos; ++i) 206 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 207 printf("\n"); 208 #endif 209 210 return; 211 } 212 213 /* 214 * NAME: reduce 215 * 216 * FUNCTION: Implements the reduce part of the parsing algorithm 217 * 218 * ALGORITHM: The following reductions are done. Reductions are repeated 219 * until no more are possible. 220 * 221 * Old TOS New TOS 222 * <stmt> <stmt> <stmtl> 223 * <stmtl> <stmt> <stmtl> 224 * do <stmt> "dostmt" 225 * if <stmt> "ifstmt" 226 * switch <stmt> <stmt> 227 * decl <stmt> <stmt> 228 * "ifelse" <stmt> <stmt> 229 * for <stmt> <stmt> 230 * while <stmt> <stmt> 231 * "dostmt" while <stmt> 232 * 233 * On each reduction, ps.i_l_follow (the indentation for the following line) 234 * is set to the indentation level associated with the old TOS. 235 * 236 * PARAMETERS: None 237 * 238 * RETURNS: Nothing 239 * 240 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 241 * 242 * CALLS: None 243 * 244 * CALLED BY: parse 245 * 246 * HISTORY: initial coding November 1976 D A Willcox of CAC 247 * 248 */ 249 /*----------------------------------------------*\ 250 | REDUCTION PHASE | 251 \*----------------------------------------------*/ 252 void 253 reduce() 254 { 255 256 register 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.p_stack[--ps.tos] = stmt; 322 break; 323 } 324 else 325 return; 326 327 default: /* anything else on top */ 328 return; 329 330 } 331 } 332 } 333