usr.bin/indent/parse.c

   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  *
   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. Neither the name of the University nor the names of its contributors
  16  *    may be used to endorse or promote products derived from this software
  17  *    without specific prior written permission.
  18  *
  19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  29  * SUCH DAMAGE.
  30  */
  31
  32 /*
  33  * Copyright (c) 1976 Board of Trustees of the University of Illinois.
  34  * Copyright (c) 1985 Sun Microsystems, Inc.
  35  * All rights reserved.
  36  *
  37  * Redistribution and use in source and binary forms, with or without
  38  * modification, are permitted provided that the following conditions
  39  * are met:
  40  * 1. Redistributions of source code must retain the above copyright
  41  *    notice, this list of conditions and the following disclaimer.
  42  * 2. Redistributions in binary form must reproduce the above copyright
  43  *    notice, this list of conditions and the following disclaimer in the
  44  *    documentation and/or other materials provided with the distribution.
  45  * 3. All advertising materials mentioning features or use of this software
  46  *    must display the following acknowledgement:
  47  *      This product includes software developed by the University of
  48  *      California, Berkeley and its contributors.
  49  * 4. Neither the name of the University nor the names of its contributors
  50  *    may be used to endorse or promote products derived from this software
  51  *    without specific prior written permission.
  52  *
  53  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  54  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  55  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  56  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  57  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  58  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  59  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  60  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  61  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  62  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  63  * SUCH DAMAGE.
  64  */
  65
  66 #include <sys/cdefs.h>
  67 #ifndef lint
  68 #if 0
  69 static char sccsid[] = "@(#)parse.c     8.1 (Berkeley) 6/6/93";
  70 #else
  71 __RCSID("$NetBSD: parse.c,v 1.6 2002/05/26 22:53:38 wiz Exp $");
  72 #endif
  73 #endif                          /* not lint */
  74
  75 #include <stdio.h>
  76 #include "indent_globs.h"
  77 #include "indent_codes.h"
  78
  79 /* tk: the code for the construct scanned */
  80 void
  81 parse(int tk)
  82 {
  83         int     i;
  84
  85 #ifdef debug
  86         printf("%2d - %s\n", tk, token);
  87 #endif
  88
  89         while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
  90                 /* true if we have an if without an else */
  91                 ps.p_stack[ps.tos] = stmt;      /* apply the if(..) stmt ::=
  92                                                  * stmt reduction */
  93                 reduce();       /* see if this allows any reduction */
  94         }
  95
  96
  97         switch (tk) {           /* go on and figure out what to do with the
  98                                  * input */
  99
 100         case decl:              /* scanned a declaration word */
 101                 ps.search_brace = btype_2;
 102                 /* indicate that following brace should be on same line */
 103                 if (ps.p_stack[ps.tos] != decl) {       /* only put one
 104                                                          * declaration onto
 105                                                          * stack */
 106                         break_comma = true;     /* while in declaration,
 107                                                  * newline should be forced
 108                                                  * after comma */
 109                         ps.p_stack[++ps.tos] = decl;
 110                         ps.il[ps.tos] = ps.i_l_follow;
 111
 112                         if (ps.ljust_decl) {    /* only do if we want left
 113                                                  * justified declarations */
 114                                 ps.ind_level = 0;
 115                                 for (i = ps.tos - 1; i > 0; --i)
 116                                         if (ps.p_stack[i] == decl)
 117                                                 ++ps.ind_level; /* indentation is number
 118                                                                  * of declaration levels
 119                                                                  * deep we are */
 120                                 ps.i_l_follow = ps.ind_level;
 121                         }
 122                 }
 123                 break;
 124
 125         case ifstmt:            /* scanned if (...) */
 126                 if (ps.p_stack[ps.tos] == elsehead && ps.else_if)       /* "else if ..." */
 127                         ps.i_l_follow = ps.il[ps.tos];
 128         case dolit:             /* 'do' */
 129         case forstmt:           /* for (...) */
 130                 ps.p_stack[++ps.tos] = tk;
 131                 ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 132                 ++ps.i_l_follow;/* subsequent statements should be indented 1 */
 133                 ps.search_brace = btype_2;
 134                 break;
 135
 136         case lbrace:            /* scanned { */
 137                 break_comma = false;    /* don't break comma in an initial
 138                                          * list */
 139                 if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
 140                     || ps.p_stack[ps.tos] == stmtl)
 141                         ++ps.i_l_follow;        /* it is a random, isolated
 142                                                  * stmt group or a declaration */
 143                 else {
 144                         if (s_code == e_code) {
 145                                 /*
 146                                  * only do this if there is nothing on the line
 147                                  */
 148                                 --ps.ind_level;
 149                                 /*
 150                                  * it is a group as part of a while, for, etc.
 151                                  */
 152                                 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
 153                                         --ps.ind_level;
 154                                 /*
 155                                  * for a switch, brace should be two levels out from the code
 156                                  */
 157                         }
 158                 }
 159
 160                 ps.p_stack[++ps.tos] = lbrace;
 161                 ps.il[ps.tos] = ps.ind_level;
 162                 ps.p_stack[++ps.tos] = stmt;
 163                 /* allow null stmt between braces */
 164                 ps.il[ps.tos] = ps.i_l_follow;
 165                 break;
 166
 167         case whilestmt: /* scanned while (...) */
 168                 if (ps.p_stack[ps.tos] == dohead) {
 169                         /* it is matched with do stmt */
 170                         ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
 171                         ps.p_stack[++ps.tos] = whilestmt;
 172                         ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 173                 } else {        /* it is a while loop */
 174                         ps.p_stack[++ps.tos] = whilestmt;
 175                         ps.il[ps.tos] = ps.i_l_follow;
 176                         ++ps.i_l_follow;
 177                         ps.search_brace = btype_2;
 178                 }
 179
 180                 break;
 181
 182         case elselit:           /* scanned an else */
 183
 184                 if (ps.p_stack[ps.tos] != ifhead)
 185                         diag(1, "Unmatched 'else'");
 186                 else {
 187                         ps.ind_level = ps.il[ps.tos];   /* indentation for else
 188                                                          * should be same as for
 189                                                          * if */
 190                         ps.i_l_follow = ps.ind_level + 1;       /* everything following
 191                                                                  * should be in 1 level */
 192                         ps.p_stack[ps.tos] = elsehead;
 193                         /* remember if with else */
 194                         ps.search_brace = btype_2 | ps.else_if;
 195                 }
 196                 break;
 197
 198         case rbrace:            /* scanned a } */
 199                 /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
 200                 if (ps.p_stack[ps.tos - 1] == lbrace) {
 201                         ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
 202                         ps.p_stack[ps.tos] = stmt;
 203                 } else
 204                         diag(1, "Stmt nesting error.");
 205                 break;
 206
 207         case swstmt:            /* had switch (...) */
 208                 ps.p_stack[++ps.tos] = swstmt;
 209                 ps.cstk[ps.tos] = case_ind;
 210                 /* save current case indent level */
 211                 ps.il[ps.tos] = ps.i_l_follow;
 212                 case_ind = ps.i_l_follow + ps.case_indent;      /* cases should be one
 213                                                                  * level down from
 214                                                                  * switch */
 215                 ps.i_l_follow += ps.case_indent + 1;    /* statements should be
 216                                                          * two levels in */
 217                 ps.search_brace = btype_2;
 218                 break;
 219
 220         case semicolon: /* this indicates a simple stmt */
 221                 break_comma = false;    /* turn off flag to break after commas
 222                                          * in a declaration */
 223                 ps.p_stack[++ps.tos] = stmt;
 224                 ps.il[ps.tos] = ps.ind_level;
 225                 break;
 226
 227         default:                /* this is an error */
 228                 diag(1, "Unknown code to parser");
 229                 return;
 230
 231
 232         }                       /* end of switch */
 233
 234         reduce();               /* see if any reduction can be done */
 235
 236 #ifdef debug
 237         for (i = 1; i <= ps.tos; ++i)
 238                 printf("(%d %d)", ps.p_stack[i], ps.il[i]);
 239         printf("\n");
 240 #endif
 241 }
 242 /*
 243  * NAME: reduce
 244  *
 245  * FUNCTION: Implements the reduce part of the parsing algorithm
 246  *
 247  * ALGORITHM: The following reductions are done.  Reductions are repeated
 248  *      until no more are possible.
 249  *
 250  * Old TOS              New TOS
 251  * <stmt> <stmt>        <stmtl>
 252  * <stmtl> <stmt>       <stmtl>
 253  * do <stmt>            "dostmt"
 254  * if <stmt>            "ifstmt"
 255  * switch <stmt>        <stmt>
 256  * decl <stmt>          <stmt>
 257  * "ifelse" <stmt>      <stmt>
 258  * for <stmt>           <stmt>
 259  * while <stmt>         <stmt>
 260  * "dostmt" while       <stmt>
 261  *
 262  * On each reduction, ps.i_l_follow (the indentation for the following line)
 263  * is set to the indentation level associated with the old TOS.
 264  *
 265  * PARAMETERS: None
 266  *
 267  * RETURNS: Nothing
 268  *
 269  * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
 270  *
 271  * CALLS: None
 272  *
 273  * CALLED BY: parse
 274  *
 275  * HISTORY: initial coding      November 1976   D A Willcox of CAC
 276  *
 277  */
 278 /*----------------------------------------------*\
 279 |   REDUCTION PHASE                                 |
 280 \*----------------------------------------------*/
 281 void
 282 reduce(void)
 283 {
 284
 285         int     i;
 286
 287         for (;;) {              /* keep looping until there is nothing left to
 288                                  * reduce */
 289
 290                 switch (ps.p_stack[ps.tos]) {
 291
 292                 case stmt:
 293                         switch (ps.p_stack[ps.tos - 1]) {
 294
 295                         case stmt:
 296                         case stmtl:
 297                                 /* stmtl stmt or stmt stmt */
 298                                 ps.p_stack[--ps.tos] = stmtl;
 299                                 break;
 300
 301                         case dolit:     /* <do> <stmt> */
 302                                 ps.p_stack[--ps.tos] = dohead;
 303                                 ps.i_l_follow = ps.il[ps.tos];
 304                                 break;
 305
 306                         case ifstmt:
 307                                 /* <if> <stmt> */
 308                                 ps.p_stack[--ps.tos] = ifhead;
 309                                 for (i = ps.tos - 1;
 310                                     (
 311                                         ps.p_stack[i] != stmt
 312                                         &&
 313                                         ps.p_stack[i] != stmtl
 314                                         &&
 315                                         ps.p_stack[i] != lbrace
 316                                     );
 317                                     --i);
 318                                 ps.i_l_follow = ps.il[i];
 319                                 /*
 320                                  * for the time being, we will assume that there is no else on
 321                                  * this if, and set the indentation level accordingly. If an
 322                                  * else is scanned, it will be fixed up later
 323                                  */
 324                                 break;
 325
 326                         case swstmt:
 327                                 /* <switch> <stmt> */
 328                                 case_ind = ps.cstk[ps.tos - 1];
 329
 330                         case decl:      /* finish of a declaration */
 331                         case elsehead:
 332                                 /* <<if> <stmt> else> <stmt> */
 333                         case forstmt:
 334                                 /* <for> <stmt> */
 335                         case whilestmt:
 336                                 /* <while> <stmt> */
 337                                 ps.p_stack[--ps.tos] = stmt;
 338                                 ps.i_l_follow = ps.il[ps.tos];
 339                                 break;
 340
 341                         default:        /* <anything else> <stmt> */
 342                                 return;
 343
 344                         }       /* end of section for <stmt> on top of stack */
 345                         break;
 346
 347                 case whilestmt:/* while (...) on top */
 348                         if (ps.p_stack[ps.tos - 1] == dohead) {
 349                                 /* it is termination of a do while */
 350                                 ps.p_stack[--ps.tos] = stmt;
 351                                 break;
 352                         } else
 353                                 return;
 354
 355                 default:        /* anything else on top */
 356                         return;
 357
 358                 }
 359         }
 360 }