1 /* $NetBSD: parse.c,v 1.6 2002/05/26 22:53:38 wiz Exp $ */ 2 3 /* 4 * Copyright (c) 1980, 1993 5 * The Regents of the University of California. All rights reserved. 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 #include <sys/cdefs.h> 40 #ifndef lint 41 #if 0 42 static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93"; 43 #else 44 __RCSID("$NetBSD: parse.c,v 1.6 2002/05/26 22:53:38 wiz Exp $"); 45 #endif 46 #endif /* not lint */ 47 48 #include <stdio.h> 49 #include "indent_globs.h" 50 #include "indent_codes.h" 51 52 /* tk: the code for the construct scanned */ 53 void 54 parse(int tk) 55 { 56 int i; 57 58 #ifdef debug 59 printf("%2d - %s\n", tk, token); 60 #endif 61 62 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 63 /* true if we have an if without an else */ 64 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= 65 * stmt reduction */ 66 reduce(); /* see if this allows any reduction */ 67 } 68 69 70 switch (tk) { /* go on and figure out what to do with the 71 * input */ 72 73 case decl: /* scanned a declaration word */ 74 ps.search_brace = btype_2; 75 /* indicate that following brace should be on same line */ 76 if (ps.p_stack[ps.tos] != decl) { /* only put one 77 * declaration onto 78 * stack */ 79 break_comma = true; /* while in declaration, 80 * newline should be forced 81 * after comma */ 82 ps.p_stack[++ps.tos] = decl; 83 ps.il[ps.tos] = ps.i_l_follow; 84 85 if (ps.ljust_decl) { /* only do if we want left 86 * justified declarations */ 87 ps.ind_level = 0; 88 for (i = ps.tos - 1; i > 0; --i) 89 if (ps.p_stack[i] == decl) 90 ++ps.ind_level; /* indentation is number 91 * of declaration levels 92 * deep we are */ 93 ps.i_l_follow = ps.ind_level; 94 } 95 } 96 break; 97 98 case ifstmt: /* scanned if (...) */ 99 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 100 ps.i_l_follow = ps.il[ps.tos]; 101 case dolit: /* 'do' */ 102 case forstmt: /* for (...) */ 103 ps.p_stack[++ps.tos] = tk; 104 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 105 ++ps.i_l_follow;/* subsequent statements should be indented 1 */ 106 ps.search_brace = btype_2; 107 break; 108 109 case lbrace: /* scanned { */ 110 break_comma = false; /* don't break comma in an initial 111 * list */ 112 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 113 || ps.p_stack[ps.tos] == stmtl) 114 ++ps.i_l_follow; /* it is a random, isolated 115 * stmt group or a declaration */ 116 else { 117 if (s_code == e_code) { 118 /* 119 * only do this if there is nothing on the line 120 */ 121 --ps.ind_level; 122 /* 123 * it is a group as part of a while, for, etc. 124 */ 125 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 126 --ps.ind_level; 127 /* 128 * for a switch, brace should be two levels out from the code 129 */ 130 } 131 } 132 133 ps.p_stack[++ps.tos] = lbrace; 134 ps.il[ps.tos] = ps.ind_level; 135 ps.p_stack[++ps.tos] = stmt; 136 /* allow null stmt between braces */ 137 ps.il[ps.tos] = ps.i_l_follow; 138 break; 139 140 case whilestmt: /* scanned while (...) */ 141 if (ps.p_stack[ps.tos] == dohead) { 142 /* it is matched with do stmt */ 143 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 144 ps.p_stack[++ps.tos] = whilestmt; 145 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 146 } else { /* it is a while loop */ 147 ps.p_stack[++ps.tos] = whilestmt; 148 ps.il[ps.tos] = ps.i_l_follow; 149 ++ps.i_l_follow; 150 ps.search_brace = btype_2; 151 } 152 153 break; 154 155 case elselit: /* scanned an else */ 156 157 if (ps.p_stack[ps.tos] != ifhead) 158 diag(1, "Unmatched 'else'"); 159 else { 160 ps.ind_level = ps.il[ps.tos]; /* indentation for else 161 * should be same as for 162 * if */ 163 ps.i_l_follow = ps.ind_level + 1; /* everything following 164 * should be in 1 level */ 165 ps.p_stack[ps.tos] = elsehead; 166 /* remember if with else */ 167 ps.search_brace = btype_2 | ps.else_if; 168 } 169 break; 170 171 case rbrace: /* scanned a } */ 172 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 173 if (ps.p_stack[ps.tos - 1] == lbrace) { 174 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 175 ps.p_stack[ps.tos] = stmt; 176 } else 177 diag(1, "Stmt nesting error."); 178 break; 179 180 case swstmt: /* had switch (...) */ 181 ps.p_stack[++ps.tos] = swstmt; 182 ps.cstk[ps.tos] = case_ind; 183 /* save current case indent level */ 184 ps.il[ps.tos] = ps.i_l_follow; 185 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 186 * level down from 187 * switch */ 188 ps.i_l_follow += ps.case_indent + 1; /* statements should be 189 * two levels in */ 190 ps.search_brace = btype_2; 191 break; 192 193 case semicolon: /* this indicates a simple stmt */ 194 break_comma = false; /* turn off flag to break after commas 195 * in a declaration */ 196 ps.p_stack[++ps.tos] = stmt; 197 ps.il[ps.tos] = ps.ind_level; 198 break; 199 200 default: /* this is an error */ 201 diag(1, "Unknown code to parser"); 202 return; 203 204 205 } /* end of switch */ 206 207 reduce(); /* see if any reduction can be done */ 208 209 #ifdef debug 210 for (i = 1; i <= ps.tos; ++i) 211 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 212 printf("\n"); 213 #endif 214 } 215 /* 216 * NAME: reduce 217 * 218 * FUNCTION: Implements the reduce part of the parsing algorithm 219 * 220 * ALGORITHM: The following reductions are done. Reductions are repeated 221 * until no more are possible. 222 * 223 * Old TOS New TOS 224 * <stmt> <stmt> <stmtl> 225 * <stmtl> <stmt> <stmtl> 226 * do <stmt> "dostmt" 227 * if <stmt> "ifstmt" 228 * switch <stmt> <stmt> 229 * decl <stmt> <stmt> 230 * "ifelse" <stmt> <stmt> 231 * for <stmt> <stmt> 232 * while <stmt> <stmt> 233 * "dostmt" while <stmt> 234 * 235 * On each reduction, ps.i_l_follow (the indentation for the following line) 236 * is set to the indentation level associated with the old TOS. 237 * 238 * PARAMETERS: None 239 * 240 * RETURNS: Nothing 241 * 242 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 243 * 244 * CALLS: None 245 * 246 * CALLED BY: parse 247 * 248 * HISTORY: initial coding November 1976 D A Willcox of CAC 249 * 250 */ 251 /*----------------------------------------------*\ 252 | REDUCTION PHASE | 253 \*----------------------------------------------*/ 254 void 255 reduce(void) 256 { 257 258 int i; 259 260 for (;;) { /* keep looping until there is nothing left to 261 * reduce */ 262 263 switch (ps.p_stack[ps.tos]) { 264 265 case stmt: 266 switch (ps.p_stack[ps.tos - 1]) { 267 268 case stmt: 269 case stmtl: 270 /* stmtl stmt or stmt stmt */ 271 ps.p_stack[--ps.tos] = stmtl; 272 break; 273 274 case dolit: /* <do> <stmt> */ 275 ps.p_stack[--ps.tos] = dohead; 276 ps.i_l_follow = ps.il[ps.tos]; 277 break; 278 279 case ifstmt: 280 /* <if> <stmt> */ 281 ps.p_stack[--ps.tos] = ifhead; 282 for (i = ps.tos - 1; 283 ( 284 ps.p_stack[i] != stmt 285 && 286 ps.p_stack[i] != stmtl 287 && 288 ps.p_stack[i] != lbrace 289 ); 290 --i); 291 ps.i_l_follow = ps.il[i]; 292 /* 293 * for the time being, we will assume that there is no else on 294 * this if, and set the indentation level accordingly. If an 295 * else is scanned, it will be fixed up later 296 */ 297 break; 298 299 case swstmt: 300 /* <switch> <stmt> */ 301 case_ind = ps.cstk[ps.tos - 1]; 302 303 case decl: /* finish of a declaration */ 304 case elsehead: 305 /* <<if> <stmt> else> <stmt> */ 306 case forstmt: 307 /* <for> <stmt> */ 308 case whilestmt: 309 /* <while> <stmt> */ 310 ps.p_stack[--ps.tos] = stmt; 311 ps.i_l_follow = ps.il[ps.tos]; 312 break; 313 314 default: /* <anything else> <stmt> */ 315 return; 316 317 } /* end of section for <stmt> on top of stack */ 318 break; 319 320 case whilestmt:/* while (...) on top */ 321 if (ps.p_stack[ps.tos - 1] == dohead) { 322 /* it is termination of a do while */ 323 ps.p_stack[--ps.tos] = stmt; 324 break; 325 } else 326 return; 327 328 default: /* anything else on top */ 329 return; 330 331 } 332 } 333 } 334