1 /*- 2 * SPDX-License-Identifier: BSD-4-Clause 3 * 4 * Copyright (c) 1985 Sun Microsystems, Inc. 5 * Copyright (c) 1980, 1993 6 * The Regents of the University of California. All rights reserved. 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 3. All advertising materials mentioning features or use of this software 18 * must display the following acknowledgement: 19 * This product includes software developed by the University of 20 * California, Berkeley and its contributors. 21 * 4. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 */ 37 38 #if 0 39 #ifndef lint 40 static char sccsid[] = "@(#)parse.c 8.1 (Berkeley) 6/6/93"; 41 #endif /* not lint */ 42 #endif 43 44 #include <sys/cdefs.h> 45 #include <sys/param.h> 46 __FBSDID("$FreeBSD$"); 47 48 #include <err.h> 49 #include <stdio.h> 50 51 #include "indent_globs.h" 52 #include "indent_codes.h" 53 #include "indent.h" 54 55 static void reduce(void); 56 57 void 58 parse(int tk) /* tk: the code for the construct scanned */ 59 { 60 int i; 61 62 #ifdef debug 63 printf("%2d - %s\n", tk, token); 64 #endif 65 66 while (ps.p_stack[ps.tos] == ifhead && tk != elselit) { 67 /* true if we have an if without an else */ 68 ps.p_stack[ps.tos] = stmt; /* apply the if(..) stmt ::= stmt 69 * reduction */ 70 reduce(); /* see if this allows any reduction */ 71 } 72 73 74 switch (tk) { /* go on and figure out what to do with the 75 * input */ 76 77 case decl: /* scanned a declaration word */ 78 ps.search_brace = btype_2; 79 /* indicate that following brace should be on same line */ 80 if (ps.p_stack[ps.tos] != decl) { /* only put one declaration 81 * onto stack */ 82 break_comma = true; /* while in declaration, newline should be 83 * forced after comma */ 84 ps.p_stack[++ps.tos] = decl; 85 ps.il[ps.tos] = ps.i_l_follow; 86 87 if (ps.ljust_decl) {/* only do if we want left justified 88 * declarations */ 89 ps.ind_level = 0; 90 for (i = ps.tos - 1; i > 0; --i) 91 if (ps.p_stack[i] == decl) 92 ++ps.ind_level; /* indentation is number of 93 * declaration levels deep we are */ 94 ps.i_l_follow = ps.ind_level; 95 } 96 } 97 break; 98 99 case ifstmt: /* scanned if (...) */ 100 if (ps.p_stack[ps.tos] == elsehead && ps.else_if) /* "else if ..." */ 101 /* 102 * Note that the stack pointer here is decremented, effectively 103 * reducing "else if" to "if". This saves a lot of stack space 104 * in case of a long "if-else-if ... else-if" sequence. 105 */ 106 ps.i_l_follow = ps.il[ps.tos--]; 107 /* the rest is the same as for dolit and forstmt */ 108 case dolit: /* 'do' */ 109 case forstmt: /* for (...) */ 110 ps.p_stack[++ps.tos] = tk; 111 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 112 ++ps.i_l_follow; /* subsequent statements should be indented 1 */ 113 ps.search_brace = btype_2; 114 break; 115 116 case lbrace: /* scanned { */ 117 break_comma = false; /* don't break comma in an initial list */ 118 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl 119 || ps.p_stack[ps.tos] == stmtl) 120 ++ps.i_l_follow; /* it is a random, isolated stmt group or a 121 * declaration */ 122 else { 123 if (s_code == e_code) { 124 /* 125 * only do this if there is nothing on the line 126 */ 127 --ps.ind_level; 128 /* 129 * it is a group as part of a while, for, etc. 130 */ 131 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1) 132 --ps.ind_level; 133 /* 134 * for a switch, brace should be two levels out from the code 135 */ 136 } 137 } 138 139 ps.p_stack[++ps.tos] = lbrace; 140 ps.il[ps.tos] = ps.ind_level; 141 ps.p_stack[++ps.tos] = stmt; 142 /* allow null stmt between braces */ 143 ps.il[ps.tos] = ps.i_l_follow; 144 break; 145 146 case whilestmt: /* scanned while (...) */ 147 if (ps.p_stack[ps.tos] == dohead) { 148 /* it is matched with do stmt */ 149 ps.ind_level = ps.i_l_follow = ps.il[ps.tos]; 150 ps.p_stack[++ps.tos] = whilestmt; 151 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow; 152 } 153 else { /* it is a while loop */ 154 ps.p_stack[++ps.tos] = whilestmt; 155 ps.il[ps.tos] = ps.i_l_follow; 156 ++ps.i_l_follow; 157 ps.search_brace = btype_2; 158 } 159 160 break; 161 162 case elselit: /* scanned an else */ 163 164 if (ps.p_stack[ps.tos] != ifhead) 165 diag2(1, "Unmatched 'else'"); 166 else { 167 ps.ind_level = ps.il[ps.tos]; /* indentation for else should 168 * be same as for if */ 169 ps.i_l_follow = ps.ind_level + 1; /* everything following should 170 * be in 1 level */ 171 ps.p_stack[ps.tos] = elsehead; 172 /* remember if with else */ 173 ps.search_brace = btype_2 | ps.else_if; 174 } 175 break; 176 177 case rbrace: /* scanned a } */ 178 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */ 179 if (ps.tos > 0 && ps.p_stack[ps.tos - 1] == lbrace) { 180 ps.ind_level = ps.i_l_follow = ps.il[--ps.tos]; 181 ps.p_stack[ps.tos] = stmt; 182 } 183 else 184 diag2(1, "Statement nesting error"); 185 break; 186 187 case swstmt: /* had switch (...) */ 188 ps.p_stack[++ps.tos] = swstmt; 189 ps.cstk[ps.tos] = case_ind; 190 /* save current case indent level */ 191 ps.il[ps.tos] = ps.i_l_follow; 192 case_ind = ps.i_l_follow + ps.case_indent; /* cases should be one 193 * level down from 194 * switch */ 195 ps.i_l_follow += ps.case_indent + 1; /* statements should be two 196 * levels in */ 197 ps.search_brace = btype_2; 198 break; 199 200 case semicolon: /* this indicates a simple stmt */ 201 break_comma = false; /* turn off flag to break after commas in a 202 * declaration */ 203 ps.p_stack[++ps.tos] = stmt; 204 ps.il[ps.tos] = ps.ind_level; 205 break; 206 207 default: /* this is an error */ 208 diag2(1, "Unknown code to parser"); 209 return; 210 211 212 } /* end of switch */ 213 214 if (ps.tos >= nitems(ps.p_stack) - 1) 215 errx(1, "Parser stack overflow"); 216 217 reduce(); /* see if any reduction can be done */ 218 219 #ifdef debug 220 for (i = 1; i <= ps.tos; ++i) 221 printf("(%d %d)", ps.p_stack[i], ps.il[i]); 222 printf("\n"); 223 #endif 224 225 return; 226 } 227 228 /* 229 * NAME: reduce 230 * 231 * FUNCTION: Implements the reduce part of the parsing algorithm 232 * 233 * ALGORITHM: The following reductions are done. Reductions are repeated 234 * until no more are possible. 235 * 236 * Old TOS New TOS 237 * <stmt> <stmt> <stmtl> 238 * <stmtl> <stmt> <stmtl> 239 * do <stmt> "dostmt" 240 * if <stmt> "ifstmt" 241 * switch <stmt> <stmt> 242 * decl <stmt> <stmt> 243 * "ifelse" <stmt> <stmt> 244 * for <stmt> <stmt> 245 * while <stmt> <stmt> 246 * "dostmt" while <stmt> 247 * 248 * On each reduction, ps.i_l_follow (the indentation for the following line) 249 * is set to the indentation level associated with the old TOS. 250 * 251 * PARAMETERS: None 252 * 253 * RETURNS: Nothing 254 * 255 * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos = 256 * 257 * CALLS: None 258 * 259 * CALLED BY: parse 260 * 261 * HISTORY: initial coding November 1976 D A Willcox of CAC 262 * 263 */ 264 /*----------------------------------------------*\ 265 | REDUCTION PHASE | 266 \*----------------------------------------------*/ 267 static void 268 reduce(void) 269 { 270 int i; 271 272 for (;;) { /* keep looping until there is nothing left to 273 * reduce */ 274 275 switch (ps.p_stack[ps.tos]) { 276 277 case stmt: 278 switch (ps.p_stack[ps.tos - 1]) { 279 280 case stmt: 281 case stmtl: 282 /* stmtl stmt or stmt stmt */ 283 ps.p_stack[--ps.tos] = stmtl; 284 break; 285 286 case dolit: /* <do> <stmt> */ 287 ps.p_stack[--ps.tos] = dohead; 288 ps.i_l_follow = ps.il[ps.tos]; 289 break; 290 291 case ifstmt: 292 /* <if> <stmt> */ 293 ps.p_stack[--ps.tos] = ifhead; 294 for (i = ps.tos - 1; 295 ( 296 ps.p_stack[i] != stmt 297 && 298 ps.p_stack[i] != stmtl 299 && 300 ps.p_stack[i] != lbrace 301 ); 302 --i); 303 ps.i_l_follow = ps.il[i]; 304 /* 305 * for the time being, we will assume that there is no else on 306 * this if, and set the indentation level accordingly. If an 307 * else is scanned, it will be fixed up later 308 */ 309 break; 310 311 case swstmt: 312 /* <switch> <stmt> */ 313 case_ind = ps.cstk[ps.tos - 1]; 314 /* FALLTHROUGH */ 315 case decl: /* finish of a declaration */ 316 case elsehead: 317 /* <<if> <stmt> else> <stmt> */ 318 case forstmt: 319 /* <for> <stmt> */ 320 case whilestmt: 321 /* <while> <stmt> */ 322 ps.p_stack[--ps.tos] = stmt; 323 ps.i_l_follow = ps.il[ps.tos]; 324 break; 325 326 default: /* <anything else> <stmt> */ 327 return; 328 329 } /* end of section for <stmt> on top of stack */ 330 break; 331 332 case whilestmt: /* while (...) on top */ 333 if (ps.p_stack[ps.tos - 1] == dohead) { 334 /* it is termination of a do while */ 335 ps.tos -= 2; 336 break; 337 } 338 else 339 return; 340 341 default: /* anything else on top */ 342 return; 343 344 } 345 } 346 } 347