1 /*- 2 * Copyright (c) 1985 Sun Microsystems, Inc. 3 * Copyright (c) 1980, 1993 4 * The Regents of the University of California. All rights reserved. 5 * 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. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by the University of 18 * California, Berkeley and its contributors. 19 * 4. Neither the name of the University nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #if 0 37 #ifndef lint 38 static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93"; 39 #endif /* not lint */ 40 #endif 41 42 #include <sys/cdefs.h> 43 __FBSDID("$FreeBSD$"); 44 45 #include <err.h> 46 #include <stdio.h> 47 #include "indent_globs.h" 48 #include "indent_codes.h" 49 #include "indent.h" 50 51 static void reduce(void); 52 53 void 54 parse(int tk) /* tk: the code for the construct scanned */ 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 ::= stmt 65 * 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 declaration 77 * onto stack */ 78 break_comma = true; /* while in declaration, newline should be 79 * forced after comma */ 80 ps.p_stack[++ps.tos] = decl; 81 ps.il[ps.tos] = ps.i_l_follow; 82 83 if (ps.ljust_decl) {/* only do if we want left justified 84 * declarations */ 85 ps.ind_level = 0; 86 for (i = ps.tos - 1; i > 0; --i) 87 if (ps.p_stack[i] == decl) 88 ++ps.ind_level; /* indentation is number of 89 * declaration levels deep we are */ 90 ps.i_l_follow = ps.ind_level; 91 } 92 } 93 break; 94 95 case ifstmt: /* scanned if (...) */ 96 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 97 /* 98 * Note that the stack pointer here is decremented, effectively 99 * reducing "else if" to "if". This saves a lot of stack space 100 * in case of a long "if-else-if ... else-if" sequence. 101 */ 102 ps.i_l_follow = ps.il[ps.tos--]; 103 /* the rest is the same as for dolit and forstmt */ 104 case dolit: /* 'do' */ 105 case forstmt: /* for (...) */ 106 ps.p_stack[++ps.tos] = tk; 107 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 108 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 109 ps.search_brace = btype_2; 110 break; 111 112 case lbrace: /* scanned { */ 113 break_comma = false; /* don't break comma in an initial list */ 114 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 115 || ps.p_stack[ps.tos] == stmtl) 116 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 117 * declaration */ 118 else { 119 if (s_code == e_code) { 120 /* 121 * only do this if there is nothing on the line 122 */ 123 --ps.ind_level; 124 /* 125 * it is a group as part of a while, for, etc. 126 */ 127 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 128 --ps.ind_level; 129 /* 130 * for a switch, brace should be two levels out from the code 131 */ 132 } 133 } 134 135 ps.p_stack[++ps.tos] = lbrace; 136 ps.il[ps.tos] = ps.ind_level; 137 ps.p_stack[++ps.tos] = stmt; 138 /* allow null stmt between braces */ 139 ps.il[ps.tos] = ps.i_l_follow; 140 break; 141 142 case whilestmt: /* scanned while (...) */ 143 if (ps.p_stack[ps.tos] == dohead) { 144 /* it is matched with do stmt */ 145 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 146 ps.p_stack[++ps.tos] = whilestmt; 147 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 148 } 149 else { /* it is a while loop */ 150 ps.p_stack[++ps.tos] = whilestmt; 151 ps.il[ps.tos] = ps.i_l_follow; 152 ++ps.i_l_follow; 153 ps.search_brace = btype_2; 154 } 155 156 break; 157 158 case elselit: /* scanned an else */ 159 160 if (ps.p_stack[ps.tos] != ifhead) 161 diag2(1, "Unmatched 'else'"); 162 else { 163 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 164 * be same as for if */ 165 ps.i_l_follow = ps.ind_level + 1; /* everything following should 166 * be in 1 level */ 167 ps.p_stack[ps.tos] = elsehead; 168 /* remember if with else */ 169 ps.search_brace = btype_2 | ps.else_if; 170 } 171 break; 172 173 case rbrace: /* scanned a } */ 174 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 175 if (ps.tos > 0 && ps.p_stack[ps.tos - 1] == lbrace) { 176 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 177 ps.p_stack[ps.tos] = stmt; 178 } 179 else 180 diag2(1, "Statement nesting error"); 181 break; 182 183 case swstmt: /* had switch (...) */ 184 ps.p_stack[++ps.tos] = swstmt; 185 ps.cstk[ps.tos] = case_ind; 186 /* save current case indent level */ 187 ps.il[ps.tos] = ps.i_l_follow; 188 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 189 * level down from 190 * switch */ 191 ps.i_l_follow += ps.case_indent + 1; /* statements should be two 192 * levels in */ 193 ps.search_brace = btype_2; 194 break; 195 196 case semicolon: /* this indicates a simple stmt */ 197 break_comma = false; /* turn off flag to break after commas in a 198 * declaration */ 199 ps.p_stack[++ps.tos] = stmt; 200 ps.il[ps.tos] = ps.ind_level; 201 break; 202 203 default: /* this is an error */ 204 diag2(1, "Unknown code to parser"); 205 return; 206 207 208 } /* end of switch */ 209 210 if (ps.tos >= STACKSIZE - 1) 211 errx(1, "Parser stack overflow"); 212 213 reduce(); /* see if any reduction can be done */ 214 215 #ifdef debug 216 for (i = 1; i <= ps.tos; ++i) 217 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 218 printf("\n"); 219 #endif 220 221 return; 222 } 223 224 /* 225 * NAME: reduce 226 * 227 * FUNCTION: Implements the reduce part of the parsing algorithm 228 * 229 * ALGORITHM: The following reductions are done. Reductions are repeated 230 * until no more are possible. 231 * 232 * Old TOS New TOS 233 * <stmt> <stmt> <stmtl> 234 * <stmtl> <stmt> <stmtl> 235 * do <stmt> "dostmt" 236 * if <stmt> "ifstmt" 237 * switch <stmt> <stmt> 238 * decl <stmt> <stmt> 239 * "ifelse" <stmt> <stmt> 240 * for <stmt> <stmt> 241 * while <stmt> <stmt> 242 * "dostmt" while <stmt> 243 * 244 * On each reduction, ps.i_l_follow (the indentation for the following line) 245 * is set to the indentation level associated with the old TOS. 246 * 247 * PARAMETERS: None 248 * 249 * RETURNS: Nothing 250 * 251 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 252 * 253 * CALLS: None 254 * 255 * CALLED BY: parse 256 * 257 * HISTORY: initial coding November 1976 D A Willcox of CAC 258 * 259 */ 260 /*----------------------------------------------*\ 261 | REDUCTION PHASE | 262 \*----------------------------------------------*/ 263 static void 264 reduce(void) 265 { 266 int i; 267 268 for (;;) { /* keep looping until there is nothing left to 269 * reduce */ 270 271 switch (ps.p_stack[ps.tos]) { 272 273 case stmt: 274 switch (ps.p_stack[ps.tos - 1]) { 275 276 case stmt: 277 case stmtl: 278 /* stmtl stmt or stmt stmt */ 279 ps.p_stack[--ps.tos] = stmtl; 280 break; 281 282 case dolit: /* <do> <stmt> */ 283 ps.p_stack[--ps.tos] = dohead; 284 ps.i_l_follow = ps.il[ps.tos]; 285 break; 286 287 case ifstmt: 288 /* <if> <stmt> */ 289 ps.p_stack[--ps.tos] = ifhead; 290 for (i = ps.tos - 1; 291 ( 292 ps.p_stack[i] != stmt 293 && 294 ps.p_stack[i] != stmtl 295 && 296 ps.p_stack[i] != lbrace 297 ); 298 --i); 299 ps.i_l_follow = ps.il[i]; 300 /* 301 * for the time being, we will assume that there is no else on 302 * this if, and set the indentation level accordingly. If an 303 * else is scanned, it will be fixed up later 304 */ 305 break; 306 307 case swstmt: 308 /* <switch> <stmt> */ 309 case_ind = ps.cstk[ps.tos - 1]; 310 /* FALLTHROUGH */ 311 case decl: /* finish of a declaration */ 312 case elsehead: 313 /* <<if> <stmt> else> <stmt> */ 314 case forstmt: 315 /* <for> <stmt> */ 316 case whilestmt: 317 /* <while> <stmt> */ 318 ps.p_stack[--ps.tos] = stmt; 319 ps.i_l_follow = ps.il[ps.tos]; 320 break; 321 322 default: /* <anything else> <stmt> */ 323 return; 324 325 } /* end of section for <stmt> on top of stack */ 326 break; 327 328 case whilestmt: /* while (...) on top */ 329 if (ps.p_stack[ps.tos - 1] == dohead) { 330 /* it is termination of a do while */ 331 ps.tos -= 2; 332 break; 333 } 334 else 335 return; 336 337 default: /* anything else on top */ 338 return; 339 340 } 341 } 342 } 343