1 /* $OpenBSD: parse.c,v 1.7 2003/06/26 21:43:07 deraadt 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. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 35 #ifndef lint 36 /*static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93";*/ 37 static char rcsid[] = "$OpenBSD: parse.c,v 1.7 2003/06/26 21:43:07 deraadt Exp $"; 38 #endif /* not lint */ 39 40 #include <stdio.h> 41 #include "indent_globs.h" 42 #include "indent_codes.h" 43 44 void reduce(void); 45 46 void 47 parse(tk) 48 int tk; /* the code for the construct scanned */ 49 { 50 int i; 51 52 #ifdef debug 53 printf("%2d - %s\n", tk, token); 54 #endif 55 56 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 57 /* true if we have an if without an else */ 58 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 59 * reduction */ 60 reduce(); /* see if this allows any reduction */ 61 } 62 63 64 switch (tk) { /* go on and figure out what to do with the 65 * input */ 66 67 case decl: /* scanned a declaration word */ 68 ps.search_brace = btype_2; 69 /* indicate that following brace should be on same line */ 70 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 71 * onto stack */ 72 break_comma = true; /* while in declaration, newline should be 73 * forced after comma */ 74 ps.p_stack[++ps.tos] = decl; 75 ps.il[ps.tos] = ps.i_l_follow; 76 77 if (ps.ljust_decl) {/* only do if we want left justified 78 * declarations */ 79 ps.ind_level = 0; 80 for (i = ps.tos - 1; i > 0; --i) 81 if (ps.p_stack[i] == decl) 82 ++ps.ind_level; /* indentation is number of 83 * declaration levels deep we are */ 84 ps.i_l_follow = ps.ind_level; 85 } 86 } 87 break; 88 89 case ifstmt: /* scanned if (...) */ 90 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 91 ps.i_l_follow = ps.il[ps.tos]; 92 case dolit: /* 'do' */ 93 case forstmt: /* for (...) */ 94 ps.p_stack[++ps.tos] = tk; 95 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 96 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 97 ps.search_brace = btype_2; 98 break; 99 100 case lbrace: /* scanned { */ 101 break_comma = false; /* don't break comma in an initial list */ 102 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 103 || ps.p_stack[ps.tos] == stmtl) 104 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 105 * declaration */ 106 else { 107 if (s_code == e_code) { 108 /* 109 * only do this if there is nothing on the line 110 */ 111 --ps.ind_level; 112 /* 113 * it is a group as part of a while, for, etc. 114 */ 115 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 116 --ps.ind_level; 117 /* 118 * for a switch, brace should be two levels out from the code 119 */ 120 } 121 } 122 123 ps.p_stack[++ps.tos] = lbrace; 124 ps.il[ps.tos] = ps.ind_level; 125 ps.p_stack[++ps.tos] = stmt; 126 /* allow null stmt between braces */ 127 ps.il[ps.tos] = ps.i_l_follow; 128 break; 129 130 case whilestmt: /* scanned while (...) */ 131 if (ps.p_stack[ps.tos] == dohead) { 132 /* it is matched with do stmt */ 133 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 134 ps.p_stack[++ps.tos] = whilestmt; 135 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 136 } 137 else { /* it is a while loop */ 138 ps.p_stack[++ps.tos] = whilestmt; 139 ps.il[ps.tos] = ps.i_l_follow; 140 ++ps.i_l_follow; 141 ps.search_brace = btype_2; 142 } 143 144 break; 145 146 case elselit: /* scanned an else */ 147 148 if (ps.p_stack[ps.tos] != ifhead) 149 diag(1, "Unmatched 'else'"); 150 else { 151 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 152 * be same as for if */ 153 ps.i_l_follow = ps.ind_level + 1; /* everything following should 154 * be in 1 level */ 155 ps.p_stack[ps.tos] = elsehead; 156 /* remember if with else */ 157 ps.search_brace = btype_2 | ps.else_if; 158 } 159 break; 160 161 case rbrace: /* scanned a } */ 162 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 163 if (ps.p_stack[ps.tos - 1] == lbrace) { 164 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 165 ps.p_stack[ps.tos] = stmt; 166 } 167 else 168 diag(1, "Stmt nesting error."); 169 break; 170 171 case swstmt: /* had switch (...) */ 172 ps.p_stack[++ps.tos] = swstmt; 173 ps.cstk[ps.tos] = case_ind; 174 /* save current case indent level */ 175 ps.il[ps.tos] = ps.i_l_follow; 176 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 177 * level down from 178 * switch */ 179 ps.i_l_follow += ps.case_indent + 1; /* statements should be two 180 * levels in */ 181 ps.search_brace = btype_2; 182 break; 183 184 case semicolon: /* this indicates a simple stmt */ 185 break_comma = false; /* turn off flag to break after commas in a 186 * declaration */ 187 ps.p_stack[++ps.tos] = stmt; 188 ps.il[ps.tos] = ps.ind_level; 189 break; 190 191 default: /* this is an error */ 192 diag(1, "Unknown code to parser"); 193 return; 194 195 196 } /* end of switch */ 197 198 reduce(); /* see if any reduction can be done */ 199 200 #ifdef debug 201 for (i = 1; i <= ps.tos; ++i) 202 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 203 printf("\n"); 204 #endif 205 206 return; 207 } 208 209 /* 210 * NAME: reduce 211 * 212 * FUNCTION: Implements the reduce part of the parsing algorithm 213 * 214 * ALGORITHM: The following reductions are done. Reductions are repeated 215 * until no more are possible. 216 * 217 * Old TOS New TOS 218 * <stmt> <stmt> <stmtl> 219 * <stmtl> <stmt> <stmtl> 220 * do <stmt> "dostmt" 221 * if <stmt> "ifstmt" 222 * switch <stmt> <stmt> 223 * decl <stmt> <stmt> 224 * "ifelse" <stmt> <stmt> 225 * for <stmt> <stmt> 226 * while <stmt> <stmt> 227 * "dostmt" while <stmt> 228 * 229 * On each reduction, ps.i_l_follow (the indentation for the following line) 230 * is set to the indentation level associated with the old TOS. 231 * 232 * PARAMETERS: None 233 * 234 * RETURNS: Nothing 235 * 236 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 237 * 238 * CALLS: None 239 * 240 * CALLED BY: parse 241 * 242 * HISTORY: initial coding November 1976 D A Willcox of CAC 243 * 244 */ 245 /*----------------------------------------------*\ 246 | REDUCTION PHASE | 247 \*----------------------------------------------*/ 248 void 249 reduce(void) 250 { 251 252 int i; 253 254 for (;;) { /* keep looping until there is nothing left to 255 * reduce */ 256 257 switch (ps.p_stack[ps.tos]) { 258 259 case stmt: 260 switch (ps.p_stack[ps.tos - 1]) { 261 262 case stmt: 263 case stmtl: 264 /* stmtl stmt or stmt stmt */ 265 ps.p_stack[--ps.tos] = stmtl; 266 break; 267 268 case dolit: /* <do> <stmt> */ 269 ps.p_stack[--ps.tos] = dohead; 270 ps.i_l_follow = ps.il[ps.tos]; 271 break; 272 273 case ifstmt: 274 /* <if> <stmt> */ 275 ps.p_stack[--ps.tos] = ifhead; 276 for (i = ps.tos - 1; 277 ( 278 ps.p_stack[i] != stmt 279 && 280 ps.p_stack[i] != stmtl 281 && 282 ps.p_stack[i] != lbrace 283 ); 284 --i); 285 ps.i_l_follow = ps.il[i]; 286 /* 287 * for the time being, we will assume that there is no else on 288 * this if, and set the indentation level accordingly. If an 289 * else is scanned, it will be fixed up later 290 */ 291 break; 292 293 case swstmt: 294 /* <switch> <stmt> */ 295 case_ind = ps.cstk[ps.tos - 1]; 296 297 case decl: /* finish of a declaration */ 298 case elsehead: 299 /* <<if> <stmt> else> <stmt> */ 300 case forstmt: 301 /* <for> <stmt> */ 302 case whilestmt: 303 /* <while> <stmt> */ 304 ps.p_stack[--ps.tos] = stmt; 305 ps.i_l_follow = ps.il[ps.tos]; 306 break; 307 308 default: /* <anything else> <stmt> */ 309 return; 310 311 } /* end of section for <stmt> on top of stack */ 312 break; 313 314 case whilestmt: /* while (...) on top */ 315 if (ps.p_stack[ps.tos - 1] == dohead) { 316 /* it is termination of a do while */ 317 ps.p_stack[--ps.tos] = stmt; 318 break; 319 } 320 else 321 return; 322 323 default: /* anything else on top */ 324 return; 325 326 } 327 } 328 } 329