usr.bin/indent/parse.c

   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             ps.i_l_follow = ps.il[ps.tos];
  98     case dolit:         /* 'do' */
  99     case forstmt:               /* for (...) */
 100         ps.p_stack[++ps.tos] = tk;
 101         ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 102         ++ps.i_l_follow;        /* subsequent statements should be indented 1 */
 103         ps.search_brace = btype_2;
 104         break;
 105
 106     case lbrace:                /* scanned { */
 107         break_comma = false;    /* don't break comma in an initial list */
 108         if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
 109                 || ps.p_stack[ps.tos] == stmtl)
 110             ++ps.i_l_follow;    /* it is a random, isolated stmt group or a
 111                                  * declaration */
 112         else {
 113             if (s_code == e_code) {
 114                 /*
 115                  * only do this if there is nothing on the line
 116                  */
 117                 --ps.ind_level;
 118                 /*
 119                  * it is a group as part of a while, for, etc.
 120                  */
 121                 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
 122                     --ps.ind_level;
 123                 /*
 124                  * for a switch, brace should be two levels out from the code
 125                  */
 126             }
 127         }
 128
 129         ps.p_stack[++ps.tos] = lbrace;
 130         ps.il[ps.tos] = ps.ind_level;
 131         ps.p_stack[++ps.tos] = stmt;
 132         /* allow null stmt between braces */
 133         ps.il[ps.tos] = ps.i_l_follow;
 134         break;
 135
 136     case whilestmt:             /* scanned while (...) */
 137         if (ps.p_stack[ps.tos] == dohead) {
 138             /* it is matched with do stmt */
 139             ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
 140             ps.p_stack[++ps.tos] = whilestmt;
 141             ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 142         }
 143         else {                  /* it is a while loop */
 144             ps.p_stack[++ps.tos] = whilestmt;
 145             ps.il[ps.tos] = ps.i_l_follow;
 146             ++ps.i_l_follow;
 147             ps.search_brace = btype_2;
 148         }
 149
 150         break;
 151
 152     case elselit:               /* scanned an else */
 153
 154         if (ps.p_stack[ps.tos] != ifhead)
 155             diag2(1, "Unmatched 'else'");
 156         else {
 157             ps.ind_level = ps.il[ps.tos];       /* indentation for else should
 158                                                  * be same as for if */
 159             ps.i_l_follow = ps.ind_level + 1;   /* everything following should
 160                                                  * be in 1 level */
 161             ps.p_stack[ps.tos] = elsehead;
 162             /* remember if with else */
 163             ps.search_brace = btype_2 | ps.else_if;
 164         }
 165         break;
 166
 167     case rbrace:                /* scanned a } */
 168         /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
 169         if (ps.p_stack[ps.tos - 1] == lbrace) {
 170             ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
 171             ps.p_stack[ps.tos] = stmt;
 172         }
 173         else
 174             diag2(1, "Statement nesting error");
 175         break;
 176
 177     case swstmt:                /* had switch (...) */
 178         ps.p_stack[++ps.tos] = swstmt;
 179         ps.cstk[ps.tos] = case_ind;
 180         /* save current case indent level */
 181         ps.il[ps.tos] = ps.i_l_follow;
 182         case_ind = ps.i_l_follow + ps.case_indent;      /* cases should be one
 183                                                          * level down from
 184                                                          * switch */
 185         ps.i_l_follow += ps.case_indent + 1;    /* statements should be two
 186                                                  * levels in */
 187         ps.search_brace = btype_2;
 188         break;
 189
 190     case semicolon:             /* this indicates a simple stmt */
 191         break_comma = false;    /* turn off flag to break after commas in a
 192                                  * declaration */
 193         ps.p_stack[++ps.tos] = stmt;
 194         ps.il[ps.tos] = ps.ind_level;
 195         break;
 196
 197     default:                    /* this is an error */
 198         diag2(1, "Unknown code to parser");
 199         return;
 200
 201
 202     }                           /* end of switch */
 203
 204     if (ps.tos >= STACKSIZE)
 205         errx(1, "Parser stack overflow");
 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     return;
 216 }
 217
 218 /*
 219  * NAME: reduce
 220  *
 221  * FUNCTION: Implements the reduce part of the parsing algorithm
 222  *
 223  * ALGORITHM: The following reductions are done.  Reductions are repeated
 224  *      until no more are possible.
 225  *
 226  * Old TOS              New TOS
 227  * <stmt> <stmt>        <stmtl>
 228  * <stmtl> <stmt>       <stmtl>
 229  * do <stmt>            "dostmt"
 230  * if <stmt>            "ifstmt"
 231  * switch <stmt>        <stmt>
 232  * decl <stmt>          <stmt>
 233  * "ifelse" <stmt>      <stmt>
 234  * for <stmt>           <stmt>
 235  * while <stmt>         <stmt>
 236  * "dostmt" while       <stmt>
 237  *
 238  * On each reduction, ps.i_l_follow (the indentation for the following line)
 239  * is set to the indentation level associated with the old TOS.
 240  *
 241  * PARAMETERS: None
 242  *
 243  * RETURNS: Nothing
 244  *
 245  * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
 246  *
 247  * CALLS: None
 248  *
 249  * CALLED BY: parse
 250  *
 251  * HISTORY: initial coding      November 1976   D A Willcox of CAC
 252  *
 253  */
 254 /*----------------------------------------------*\
 255 |   REDUCTION PHASE                                 |
 256 \*----------------------------------------------*/
 257 static void
 258 reduce(void)
 259 {
 260     int i;
 261
 262     for (;;) {                  /* keep looping until there is nothing left to
 263                                  * reduce */
 264
 265         switch (ps.p_stack[ps.tos]) {
 266
 267         case stmt:
 268             switch (ps.p_stack[ps.tos - 1]) {
 269
 270             case stmt:
 271             case stmtl:
 272                 /* stmtl stmt or stmt stmt */
 273                 ps.p_stack[--ps.tos] = stmtl;
 274                 break;
 275
 276             case dolit: /* <do> <stmt> */
 277                 ps.p_stack[--ps.tos] = dohead;
 278                 ps.i_l_follow = ps.il[ps.tos];
 279                 break;
 280
 281             case ifstmt:
 282                 /* <if> <stmt> */
 283                 ps.p_stack[--ps.tos] = ifhead;
 284                 for (i = ps.tos - 1;
 285                         (
 286                          ps.p_stack[i] != stmt
 287                          &&
 288                          ps.p_stack[i] != stmtl
 289                          &&
 290                          ps.p_stack[i] != lbrace
 291                          );
 292                         --i);
 293                 ps.i_l_follow = ps.il[i];
 294                 /*
 295                  * for the time being, we will assume that there is no else on
 296                  * this if, and set the indentation level accordingly. If an
 297                  * else is scanned, it will be fixed up later
 298                  */
 299                 break;
 300
 301             case swstmt:
 302                 /* <switch> <stmt> */
 303                 case_ind = ps.cstk[ps.tos - 1];
 304
 305             case decl:          /* finish of a declaration */
 306             case elsehead:
 307                 /* <<if> <stmt> else> <stmt> */
 308             case forstmt:
 309                 /* <for> <stmt> */
 310             case whilestmt:
 311                 /* <while> <stmt> */
 312                 ps.p_stack[--ps.tos] = stmt;
 313                 ps.i_l_follow = ps.il[ps.tos];
 314                 break;
 315
 316             default:            /* <anything else> <stmt> */
 317                 return;
 318
 319             }                   /* end of section for <stmt> on top of stack */
 320             break;
 321
 322         case whilestmt: /* while (...) on top */
 323             if (ps.p_stack[ps.tos - 1] == dohead) {
 324                 /* it is termination of a do while */
 325                 ps.tos -= 2;
 326                 break;
 327             }
 328             else
 329                 return;
 330
 331         default:                /* anything else on top */
 332             return;
 333
 334         }
 335     }
 336 }