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  * @(#)parse.c  8.1 (Berkeley) 6/6/93
  36  * $FreeBSD: src/usr.bin/indent/parse.c,v 1.10 2003/06/15 09:28:17 charnier Exp $
  37  * $DragonFly: src/usr.bin/indent/parse.c,v 1.3 2005/04/10 20:55:38 drhodus Exp $
  38  */
  39
  40 #include <stdio.h>
  41 #include "indent_globs.h"
  42 #include "indent_codes.h"
  43 #include "indent.h"
  44
  45 static void reduce(void);
  46
  47 void
  48 parse(int tk) /* tk: the code for the construct scanned */
  49 {
  50     int         i;
  51
  52 #ifdef debug
  53     printf("%2d - %s\n", tk, token);
  54 #endif
  55
  56     while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
  57         /* true if we have an if without an else */
  58         ps.p_stack[ps.tos] = stmt;      /* apply the if(..) stmt ::= stmt
  59                                          * reduction */
  60         reduce();               /* see if this allows any reduction */
  61     }
  62
  63
  64     switch (tk) {               /* go on and figure out what to do with the
  65                                  * input */
  66
  67     case decl:                  /* scanned a declaration word */
  68         ps.search_brace = btype_2;
  69         /* indicate that following brace should be on same line */
  70         if (ps.p_stack[ps.tos] != decl) {       /* only put one declaration
  71                                                  * onto stack */
  72             break_comma = true; /* while in declaration, newline should be
  73                                  * forced after comma */
  74             ps.p_stack[++ps.tos] = decl;
  75             ps.il[ps.tos] = ps.i_l_follow;
  76
  77             if (ps.ljust_decl) {/* only do if we want left justified
  78                                  * declarations */
  79                 ps.ind_level = 0;
  80                 for (i = ps.tos - 1; i > 0; --i)
  81                     if (ps.p_stack[i] == decl)
  82                         ++ps.ind_level; /* indentation is number of
  83                                          * declaration levels deep we are */
  84                 ps.i_l_follow = ps.ind_level;
  85             }
  86         }
  87         break;
  88
  89     case ifstmt:                /* scanned if (...) */
  90         if (ps.p_stack[ps.tos] == elsehead && ps.else_if)       /* "else if ..." */
  91             ps.i_l_follow = ps.il[ps.tos];
  92     case dolit:         /* 'do' */
  93     case forstmt:               /* for (...) */
  94         ps.p_stack[++ps.tos] = tk;
  95         ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
  96         ++ps.i_l_follow;        /* subsequent statements should be indented 1 */
  97         ps.search_brace = btype_2;
  98         break;
  99
 100     case lbrace:                /* scanned { */
 101         break_comma = false;    /* don't break comma in an initial list */
 102         if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
 103                 || ps.p_stack[ps.tos] == stmtl)
 104             ++ps.i_l_follow;    /* it is a random, isolated stmt group or a
 105                                  * declaration */
 106         else {
 107             if (s_code == e_code) {
 108                 /*
 109                  * only do this if there is nothing on the line
 110                  */
 111                 --ps.ind_level;
 112                 /*
 113                  * it is a group as part of a while, for, etc.
 114                  */
 115                 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
 116                     --ps.ind_level;
 117                 /*
 118                  * for a switch, brace should be two levels out from the code
 119                  */
 120             }
 121         }
 122
 123         ps.p_stack[++ps.tos] = lbrace;
 124         ps.il[ps.tos] = ps.ind_level;
 125         ps.p_stack[++ps.tos] = stmt;
 126         /* allow null stmt between braces */
 127         ps.il[ps.tos] = ps.i_l_follow;
 128         break;
 129
 130     case whilestmt:             /* scanned while (...) */
 131         if (ps.p_stack[ps.tos] == dohead) {
 132             /* it is matched with do stmt */
 133             ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
 134             ps.p_stack[++ps.tos] = whilestmt;
 135             ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 136         }
 137         else {                  /* it is a while loop */
 138             ps.p_stack[++ps.tos] = whilestmt;
 139             ps.il[ps.tos] = ps.i_l_follow;
 140             ++ps.i_l_follow;
 141             ps.search_brace = btype_2;
 142         }
 143
 144         break;
 145
 146     case elselit:               /* scanned an else */
 147
 148         if (ps.p_stack[ps.tos] != ifhead)
 149             diag2(1, "Unmatched 'else'");
 150         else {
 151             ps.ind_level = ps.il[ps.tos];       /* indentation for else should
 152                                                  * be same as for if */
 153             ps.i_l_follow = ps.ind_level + 1;   /* everything following should
 154                                                  * be in 1 level */
 155             ps.p_stack[ps.tos] = elsehead;
 156             /* remember if with else */
 157             ps.search_brace = btype_2 | ps.else_if;
 158         }
 159         break;
 160
 161     case rbrace:                /* scanned a } */
 162         /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
 163         if (ps.p_stack[ps.tos - 1] == lbrace) {
 164             ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
 165             ps.p_stack[ps.tos] = stmt;
 166         }
 167         else
 168             diag2(1, "Statement nesting error");
 169         break;
 170
 171     case swstmt:                /* had switch (...) */
 172         ps.p_stack[++ps.tos] = swstmt;
 173         ps.cstk[ps.tos] = case_ind;
 174         /* save current case indent level */
 175         ps.il[ps.tos] = ps.i_l_follow;
 176         case_ind = ps.i_l_follow + ps.case_indent;      /* cases should be one
 177                                                          * level down from
 178                                                          * switch */
 179         ps.i_l_follow += ps.case_indent + 1;    /* statements should be two
 180                                                  * levels in */
 181         ps.search_brace = btype_2;
 182         break;
 183
 184     case semicolon:             /* this indicates a simple stmt */
 185         break_comma = false;    /* turn off flag to break after commas in a
 186                                  * declaration */
 187         ps.p_stack[++ps.tos] = stmt;
 188         ps.il[ps.tos] = ps.ind_level;
 189         break;
 190
 191     default:                    /* this is an error */
 192         diag2(1, "Unknown code to parser");
 193         return;
 194
 195
 196     }                           /* end of switch */
 197
 198     reduce();                   /* see if any reduction can be done */
 199
 200 #ifdef debug
 201     for (i = 1; i <= ps.tos; ++i)
 202         printf("(%d %d)", ps.p_stack[i], ps.il[i]);
 203     printf("\n");
 204 #endif
 205
 206     return;
 207 }
 208
 209 /*
 210  * NAME: reduce
 211  *
 212  * FUNCTION: Implements the reduce part of the parsing algorithm
 213  *
 214  * ALGORITHM: The following reductions are done.  Reductions are repeated
 215  *      until no more are possible.
 216  *
 217  * Old TOS              New TOS
 218  * <stmt> <stmt>        <stmtl>
 219  * <stmtl> <stmt>       <stmtl>
 220  * do <stmt>            "dostmt"
 221  * if <stmt>            "ifstmt"
 222  * switch <stmt>        <stmt>
 223  * decl <stmt>          <stmt>
 224  * "ifelse" <stmt>      <stmt>
 225  * for <stmt>           <stmt>
 226  * while <stmt>         <stmt>
 227  * "dostmt" while       <stmt>
 228  *
 229  * On each reduction, ps.i_l_follow (the indentation for the following line)
 230  * is set to the indentation level associated with the old TOS.
 231  *
 232  * PARAMETERS: None
 233  *
 234  * RETURNS: Nothing
 235  *
 236  * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
 237  *
 238  * CALLS: None
 239  *
 240  * CALLED BY: parse
 241  *
 242  * HISTORY: initial coding      November 1976   D A Willcox of CAC
 243  *
 244  */
 245 /*----------------------------------------------*\
 246 |   REDUCTION PHASE                                 |
 247 \*----------------------------------------------*/
 248 static void
 249 reduce(void)
 250 {
 251     int i;
 252
 253     for (;;) {                  /* keep looping until there is nothing left to
 254                                  * reduce */
 255
 256         switch (ps.p_stack[ps.tos]) {
 257
 258         case stmt:
 259             switch (ps.p_stack[ps.tos - 1]) {
 260
 261             case stmt:
 262             case stmtl:
 263                 /* stmtl stmt or stmt stmt */
 264                 ps.p_stack[--ps.tos] = stmtl;
 265                 break;
 266
 267             case dolit: /* <do> <stmt> */
 268                 ps.p_stack[--ps.tos] = dohead;
 269                 ps.i_l_follow = ps.il[ps.tos];
 270                 break;
 271
 272             case ifstmt:
 273                 /* <if> <stmt> */
 274                 ps.p_stack[--ps.tos] = ifhead;
 275                 for (i = ps.tos - 1;
 276                         (
 277                          ps.p_stack[i] != stmt
 278                          &&
 279                          ps.p_stack[i] != stmtl
 280                          &&
 281                          ps.p_stack[i] != lbrace
 282                          );
 283                         --i);
 284                 ps.i_l_follow = ps.il[i];
 285                 /*
 286                  * for the time being, we will assume that there is no else on
 287                  * this if, and set the indentation level accordingly. If an
 288                  * else is scanned, it will be fixed up later
 289                  */
 290                 break;
 291
 292             case swstmt:
 293                 /* <switch> <stmt> */
 294                 case_ind = ps.cstk[ps.tos - 1];
 295
 296             case decl:          /* finish of a declaration */
 297             case elsehead:
 298                 /* <<if> <stmt> else> <stmt> */
 299             case forstmt:
 300                 /* <for> <stmt> */
 301             case whilestmt:
 302                 /* <while> <stmt> */
 303                 ps.p_stack[--ps.tos] = stmt;
 304                 ps.i_l_follow = ps.il[ps.tos];
 305                 break;
 306
 307             default:            /* <anything else> <stmt> */
 308                 return;
 309
 310             }                   /* end of section for <stmt> on top of stack */
 311             break;
 312
 313         case whilestmt: /* while (...) on top */
 314             if (ps.p_stack[ps.tos - 1] == dohead) {
 315                 /* it is termination of a do while */
 316                 ps.tos -= 2;
 317                 break;
 318             }
 319             else
 320                 return;
 321
 322         default:                /* anything else on top */
 323             return;
 324
 325         }
 326     }
 327 }