1 /* $OpenBSD: parse.c,v 1.9 2009/10/27 23:59:39 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 #include <stdio.h> 36 #include "indent_globs.h" 37 #include "indent_codes.h" 38 39 void reduce(void); 40 41 void 42 parse(int tk) /* the code for the construct scanned */ 43 { 44 int i; 45 46 #ifdef debug 47 printf("%2d - %s\n", tk, token); 48 #endif 49 50 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 51 /* true if we have an if without an else */ 52 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 53 * reduction */ 54 reduce(); /* see if this allows any reduction */ 55 } 56 57 58 switch (tk) { /* go on and figure out what to do with the 59 * input */ 60 61 case decl: /* scanned a declaration word */ 62 ps.search_brace = btype_2; 63 /* indicate that following brace should be on same line */ 64 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 65 * onto stack */ 66 break_comma = true; /* while in declaration, newline should be 67 * forced after comma */ 68 ps.p_stack[++ps.tos] = decl; 69 ps.il[ps.tos] = ps.i_l_follow; 70 71 if (ps.ljust_decl) {/* only do if we want left justified 72 * declarations */ 73 ps.ind_level = 0; 74 for (i = ps.tos - 1; i > 0; --i) 75 if (ps.p_stack[i] == decl) 76 ++ps.ind_level; /* indentation is number of 77 * declaration levels deep we are */ 78 ps.i_l_follow = ps.ind_level; 79 } 80 } 81 break; 82 83 case ifstmt: /* scanned if (...) */ 84 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 85 ps.i_l_follow = ps.il[ps.tos]; 86 case dolit: /* 'do' */ 87 case forstmt: /* for (...) */ 88 ps.p_stack[++ps.tos] = tk; 89 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 90 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 91 ps.search_brace = btype_2; 92 break; 93 94 case lbrace: /* scanned { */ 95 break_comma = false; /* don't break comma in an initial list */ 96 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 97 || ps.p_stack[ps.tos] == stmtl) 98 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 99 * declaration */ 100 else { 101 if (s_code == e_code) { 102 /* 103 * only do this if there is nothing on the line 104 */ 105 --ps.ind_level; 106 /* 107 * it is a group as part of a while, for, etc. 108 */ 109 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 110 --ps.ind_level; 111 /* 112 * for a switch, brace should be two levels out from the code 113 */ 114 } 115 } 116 117 ps.p_stack[++ps.tos] = lbrace; 118 ps.il[ps.tos] = ps.ind_level; 119 ps.p_stack[++ps.tos] = stmt; 120 /* allow null stmt between braces */ 121 ps.il[ps.tos] = ps.i_l_follow; 122 break; 123 124 case whilestmt: /* scanned while (...) */ 125 if (ps.p_stack[ps.tos] == dohead) { 126 /* it is matched with do stmt */ 127 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 128 ps.p_stack[++ps.tos] = whilestmt; 129 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 130 } 131 else { /* it is a while loop */ 132 ps.p_stack[++ps.tos] = whilestmt; 133 ps.il[ps.tos] = ps.i_l_follow; 134 ++ps.i_l_follow; 135 ps.search_brace = btype_2; 136 } 137 138 break; 139 140 case elselit: /* scanned an else */ 141 142 if (ps.p_stack[ps.tos] != ifhead) 143 diag(1, "Unmatched 'else'"); 144 else { 145 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 146 * be same as for if */ 147 ps.i_l_follow = ps.ind_level + 1; /* everything following should 148 * be in 1 level */ 149 ps.p_stack[ps.tos] = elsehead; 150 /* remember if with else */ 151 ps.search_brace = btype_2 | ps.else_if; 152 } 153 break; 154 155 case rbrace: /* scanned a } */ 156 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 157 if (ps.p_stack[ps.tos - 1] == lbrace) { 158 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 159 ps.p_stack[ps.tos] = stmt; 160 } 161 else 162 diag(1, "Stmt nesting error."); 163 break; 164 165 case swstmt: /* had switch (...) */ 166 ps.p_stack[++ps.tos] = swstmt; 167 ps.cstk[ps.tos] = case_ind; 168 /* save current case indent level */ 169 ps.il[ps.tos] = ps.i_l_follow; 170 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 171 * level down from 172 * switch */ 173 ps.i_l_follow += ps.case_indent + 1; /* statements should be two 174 * levels in */ 175 ps.search_brace = btype_2; 176 break; 177 178 case semicolon: /* this indicates a simple stmt */ 179 break_comma = false; /* turn off flag to break after commas in a 180 * declaration */ 181 ps.p_stack[++ps.tos] = stmt; 182 ps.il[ps.tos] = ps.ind_level; 183 break; 184 185 default: /* this is an error */ 186 diag(1, "Unknown code to parser"); 187 return; 188 189 190 } /* end of switch */ 191 192 reduce(); /* see if any reduction can be done */ 193 194 #ifdef debug 195 for (i = 1; i <= ps.tos; ++i) 196 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 197 printf("\n"); 198 #endif 199 200 return; 201 } 202 203 /* 204 * NAME: reduce 205 * 206 * FUNCTION: Implements the reduce part of the parsing algorithm 207 * 208 * ALGORITHM: The following reductions are done. Reductions are repeated 209 * until no more are possible. 210 * 211 * Old TOS New TOS 212 * <stmt> <stmt> <stmtl> 213 * <stmtl> <stmt> <stmtl> 214 * do <stmt> "dostmt" 215 * if <stmt> "ifstmt" 216 * switch <stmt> <stmt> 217 * decl <stmt> <stmt> 218 * "ifelse" <stmt> <stmt> 219 * for <stmt> <stmt> 220 * while <stmt> <stmt> 221 * "dostmt" while <stmt> 222 * 223 * On each reduction, ps.i_l_follow (the indentation for the following line) 224 * is set to the indentation level associated with the old TOS. 225 * 226 * PARAMETERS: None 227 * 228 * RETURNS: Nothing 229 * 230 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 231 * 232 * CALLS: None 233 * 234 * CALLED BY: parse 235 * 236 * HISTORY: initial coding November 1976 D A Willcox of CAC 237 * 238 */ 239 /*----------------------------------------------*\ 240 | REDUCTION PHASE | 241 \*----------------------------------------------*/ 242 void 243 reduce(void) 244 { 245 246 int i; 247 248 for (;;) { /* keep looping until there is nothing left to 249 * reduce */ 250 251 switch (ps.p_stack[ps.tos]) { 252 253 case stmt: 254 switch (ps.p_stack[ps.tos - 1]) { 255 256 case stmt: 257 case stmtl: 258 /* stmtl stmt or stmt stmt */ 259 ps.p_stack[--ps.tos] = stmtl; 260 break; 261 262 case dolit: /* <do> <stmt> */ 263 ps.p_stack[--ps.tos] = dohead; 264 ps.i_l_follow = ps.il[ps.tos]; 265 break; 266 267 case ifstmt: 268 /* <if> <stmt> */ 269 ps.p_stack[--ps.tos] = ifhead; 270 for (i = ps.tos - 1; 271 ( 272 ps.p_stack[i] != stmt 273 && 274 ps.p_stack[i] != stmtl 275 && 276 ps.p_stack[i] != lbrace 277 ); 278 --i); 279 ps.i_l_follow = ps.il[i]; 280 /* 281 * for the time being, we will assume that there is no else on 282 * this if, and set the indentation level accordingly. If an 283 * else is scanned, it will be fixed up later 284 */ 285 break; 286 287 case swstmt: 288 /* <switch> <stmt> */ 289 case_ind = ps.cstk[ps.tos - 1]; 290 291 case decl: /* finish of a declaration */ 292 case elsehead: 293 /* <<if> <stmt> else> <stmt> */ 294 case forstmt: 295 /* <for> <stmt> */ 296 case whilestmt: 297 /* <while> <stmt> */ 298 ps.p_stack[--ps.tos] = stmt; 299 ps.i_l_follow = ps.il[ps.tos]; 300 break; 301 302 default: /* <anything else> <stmt> */ 303 return; 304 305 } /* end of section for <stmt> on top of stack */ 306 break; 307 308 case whilestmt: /* while (...) on top */ 309 if (ps.p_stack[ps.tos - 1] == dohead) { 310 /* it is termination of a do while */ 311 ps.p_stack[--ps.tos] = stmt; 312 break; 313 } 314 else 315 return; 316 317 default: /* anything else on top */ 318 return; 319 320 } 321 } 322 } 323