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 1.3.2.3 2001/12/06 19:28:47 schweikh Exp $
  37  * $DragonFly: src/usr.bin/indent/parse.c,v 1.3 2005/04/10 20:55:38 drhodus Exp $
  38  */
  39 #if 0
  40 #endif
  41
  42 #include <stdio.h>
  43 #include "indent_globs.h"
  44 #include "indent_codes.h"
  45 #include "indent.h"
  46
  47 static void reduce(void);
  48
  49 void
  50 parse(int tk) /* tk: the code for the construct scanned */
  51 {
  52     int         i;
  53
  54 #ifdef debug
  55     printf("%2d - %s\n", tk, token);
  56 #endif
  57
  58     while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
  59         /* true if we have an if without an else */
  60         ps.p_stack[ps.tos] = stmt;      /* apply the if(..) stmt ::= stmt
  61                                          * reduction */
  62         reduce();               /* see if this allows any reduction */
  63     }
  64
  65
  66     switch (tk) {               /* go on and figure out what to do with the
  67                                  * input */
  68
  69     case decl:                  /* scanned a declaration word */
  70         ps.search_brace = btype_2;
  71         /* indicate that following brace should be on same line */
  72         if (ps.p_stack[ps.tos] != decl) {       /* only put one declaration
  73                                                  * onto stack */
  74             break_comma = true; /* while in declaration, newline should be
  75                                  * forced after comma */
  76             ps.p_stack[++ps.tos] = decl;
  77             ps.il[ps.tos] = ps.i_l_follow;
  78
  79             if (ps.ljust_decl) {/* only do if we want left justified
  80                                  * declarations */
  81                 ps.ind_level = 0;
  82                 for (i = ps.tos - 1; i > 0; --i)
  83                     if (ps.p_stack[i] == decl)
  84                         ++ps.ind_level; /* indentation is number of
  85                                          * declaration levels deep we are */
  86                 ps.i_l_follow = ps.ind_level;
  87             }
  88         }
  89         break;
  90
  91     case ifstmt:                /* scanned if (...) */
  92         if (ps.p_stack[ps.tos] == elsehead && ps.else_if)       /* "else if ..." */
  93             ps.i_l_follow = ps.il[ps.tos];
  94     case dolit:         /* 'do' */
  95     case forstmt:               /* for (...) */
  96         ps.p_stack[++ps.tos] = tk;
  97         ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
  98         ++ps.i_l_follow;        /* subsequent statements should be indented 1 */
  99         ps.search_brace = btype_2;
 100         break;
 101
 102     case lbrace:                /* scanned { */
 103         break_comma = false;    /* don't break comma in an initial list */
 104         if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
 105                 || ps.p_stack[ps.tos] == stmtl)
 106             ++ps.i_l_follow;    /* it is a random, isolated stmt group or a
 107                                  * declaration */
 108         else {
 109             if (s_code == e_code) {
 110                 /*
 111                  * only do this if there is nothing on the line
 112                  */
 113                 --ps.ind_level;
 114                 /*
 115                  * it is a group as part of a while, for, etc.
 116                  */
 117                 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
 118                     --ps.ind_level;
 119                 /*
 120                  * for a switch, brace should be two levels out from the code
 121                  */
 122             }
 123         }
 124
 125         ps.p_stack[++ps.tos] = lbrace;
 126         ps.il[ps.tos] = ps.ind_level;
 127         ps.p_stack[++ps.tos] = stmt;
 128         /* allow null stmt between braces */
 129         ps.il[ps.tos] = ps.i_l_follow;
 130         break;
 131
 132     case whilestmt:             /* scanned while (...) */
 133         if (ps.p_stack[ps.tos] == dohead) {
 134             /* it is matched with do stmt */
 135             ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
 136             ps.p_stack[++ps.tos] = whilestmt;
 137             ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 138         }
 139         else {                  /* it is a while loop */
 140             ps.p_stack[++ps.tos] = whilestmt;
 141             ps.il[ps.tos] = ps.i_l_follow;
 142             ++ps.i_l_follow;
 143             ps.search_brace = btype_2;
 144         }
 145
 146         break;
 147
 148     case elselit:               /* scanned an else */
 149
 150         if (ps.p_stack[ps.tos] != ifhead)
 151             diag2(1, "Unmatched 'else'");
 152         else {
 153             ps.ind_level = ps.il[ps.tos];       /* indentation for else should
 154                                                  * be same as for if */
 155             ps.i_l_follow = ps.ind_level + 1;   /* everything following should
 156                                                  * be in 1 level */
 157             ps.p_stack[ps.tos] = elsehead;
 158             /* remember if with else */
 159             ps.search_brace = btype_2 | ps.else_if;
 160         }
 161         break;
 162
 163     case rbrace:                /* scanned a } */
 164         /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
 165         if (ps.p_stack[ps.tos - 1] == lbrace) {
 166             ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
 167             ps.p_stack[ps.tos] = stmt;
 168         }
 169         else
 170             diag2(1, "Stmt nesting error.");
 171         break;
 172
 173     case swstmt:                /* had switch (...) */
 174         ps.p_stack[++ps.tos] = swstmt;
 175         ps.cstk[ps.tos] = case_ind;
 176         /* save current case indent level */
 177         ps.il[ps.tos] = ps.i_l_follow;
 178         case_ind = ps.i_l_follow + ps.case_indent;      /* cases should be one
 179                                                          * level down from
 180                                                          * switch */
 181         ps.i_l_follow += ps.case_indent + 1;    /* statements should be two
 182                                                  * levels in */
 183         ps.search_brace = btype_2;
 184         break;
 185
 186     case semicolon:             /* this indicates a simple stmt */
 187         break_comma = false;    /* turn off flag to break after commas in a
 188                                  * declaration */
 189         ps.p_stack[++ps.tos] = stmt;
 190         ps.il[ps.tos] = ps.ind_level;
 191         break;
 192
 193     default:                    /* this is an error */
 194         diag2(1, "Unknown code to parser");
 195         return;
 196
 197
 198     }                           /* end of switch */
 199
 200     reduce();                   /* see if any reduction can be done */
 201
 202 #ifdef debug
 203     for (i = 1; i <= ps.tos; ++i)
 204         printf("(%d %d)", ps.p_stack[i], ps.il[i]);
 205     printf("\n");
 206 #endif
 207
 208     return;
 209 }
 210
 211 /*
 212  * NAME: reduce
 213  *
 214  * FUNCTION: Implements the reduce part of the parsing algorithm
 215  *
 216  * ALGORITHM: The following reductions are done.  Reductions are repeated
 217  *      until no more are possible.
 218  *
 219  * Old TOS              New TOS
 220  * <stmt> <stmt>        <stmtl>
 221  * <stmtl> <stmt>       <stmtl>
 222  * do <stmt>            "dostmt"
 223  * if <stmt>            "ifstmt"
 224  * switch <stmt>        <stmt>
 225  * decl <stmt>          <stmt>
 226  * "ifelse" <stmt>      <stmt>
 227  * for <stmt>           <stmt>
 228  * while <stmt>         <stmt>
 229  * "dostmt" while       <stmt>
 230  *
 231  * On each reduction, ps.i_l_follow (the indentation for the following line)
 232  * is set to the indentation level associated with the old TOS.
 233  *
 234  * PARAMETERS: None
 235  *
 236  * RETURNS: Nothing
 237  *
 238  * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
 239  *
 240  * CALLS: None
 241  *
 242  * CALLED BY: parse
 243  *
 244  * HISTORY: initial coding      November 1976   D A Willcox of CAC
 245  *
 246  */
 247 /*----------------------------------------------*\
 248 |   REDUCTION PHASE                                 |
 249 \*----------------------------------------------*/
 250 static void
 251 reduce(void)
 252 {
 253     int i;
 254
 255     for (;;) {                  /* keep looping until there is nothing left to
 256                                  * reduce */
 257
 258         switch (ps.p_stack[ps.tos]) {
 259
 260         case stmt:
 261             switch (ps.p_stack[ps.tos - 1]) {
 262
 263             case stmt:
 264             case stmtl:
 265                 /* stmtl stmt or stmt stmt */
 266                 ps.p_stack[--ps.tos] = stmtl;
 267                 break;
 268
 269             case dolit: /* <do> <stmt> */
 270                 ps.p_stack[--ps.tos] = dohead;
 271                 ps.i_l_follow = ps.il[ps.tos];
 272                 break;
 273
 274             case ifstmt:
 275                 /* <if> <stmt> */
 276                 ps.p_stack[--ps.tos] = ifhead;
 277                 for (i = ps.tos - 1;
 278                         (
 279                          ps.p_stack[i] != stmt
 280                          &&
 281                          ps.p_stack[i] != stmtl
 282                          &&
 283                          ps.p_stack[i] != lbrace
 284                          );
 285                         --i);
 286                 ps.i_l_follow = ps.il[i];
 287                 /*
 288                  * for the time being, we will assume that there is no else on
 289                  * this if, and set the indentation level accordingly. If an
 290                  * else is scanned, it will be fixed up later
 291                  */
 292                 break;
 293
 294             case swstmt:
 295                 /* <switch> <stmt> */
 296                 case_ind = ps.cstk[ps.tos - 1];
 297
 298             case decl:          /* finish of a declaration */
 299             case elsehead:
 300                 /* <<if> <stmt> else> <stmt> */
 301             case forstmt:
 302                 /* <for> <stmt> */
 303             case whilestmt:
 304                 /* <while> <stmt> */
 305                 ps.p_stack[--ps.tos] = stmt;
 306                 ps.i_l_follow = ps.il[ps.tos];
 307                 break;
 308
 309             default:            /* <anything else> <stmt> */
 310                 return;
 311
 312             }                   /* end of section for <stmt> on top of stack */
 313             break;
 314
 315         case whilestmt: /* while (...) on top */
 316             if (ps.p_stack[ps.tos - 1] == dohead) {
 317                 /* it is termination of a do while */
 318                 ps.tos -= 2;
 319                 break;
 320             }
 321             else
 322                 return;
 323
 324         default:                /* anything else on top */
 325             return;
 326
 327         }
 328     }
 329 }