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. 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  * @(#)parse.c  8.1 (Berkeley) 6/6/93
  32  * $FreeBSD: src/usr.bin/indent/parse.c,v 1.10 2003/06/15 09:28:17 charnier Exp $
  33  */
  34
  35 #include <stdio.h>
  36 #include "indent_globs.h"
  37 #include "indent_codes.h"
  38 #include "indent.h"
  39
  40 static void reduce(void);
  41
  42 void
  43 parse(int tk) /* tk: the code for the construct scanned */
  44 {
  45     int         i;
  46
  47 #ifdef debug
  48     printf("%2d - %s\n", tk, token);
  49 #endif
  50
  51     while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
  52         /* true if we have an if without an else */
  53         ps.p_stack[ps.tos] = stmt;      /* apply the if(..) stmt ::= stmt
  54                                          * reduction */
  55         reduce();               /* see if this allows any reduction */
  56     }
  57
  58
  59     switch (tk) {               /* go on and figure out what to do with the
  60                                  * input */
  61
  62     case decl:                  /* scanned a declaration word */
  63         ps.search_brace = btype_2;
  64         /* indicate that following brace should be on same line */
  65         if (ps.p_stack[ps.tos] != decl) {       /* only put one declaration
  66                                                  * onto stack */
  67             break_comma = true; /* while in declaration, newline should be
  68                                  * forced after comma */
  69             ps.p_stack[++ps.tos] = decl;
  70             ps.il[ps.tos] = ps.i_l_follow;
  71
  72             if (ps.ljust_decl) {/* only do if we want left justified
  73                                  * declarations */
  74                 ps.ind_level = 0;
  75                 for (i = ps.tos - 1; i > 0; --i)
  76                     if (ps.p_stack[i] == decl)
  77                         ++ps.ind_level; /* indentation is number of
  78                                          * declaration levels deep we are */
  79                 ps.i_l_follow = ps.ind_level;
  80             }
  81         }
  82         break;
  83
  84     case ifstmt:                /* scanned if (...) */
  85         if (ps.p_stack[ps.tos] == elsehead && ps.else_if)       /* "else if ..." */
  86             ps.i_l_follow = ps.il[ps.tos];
  87         /* FALLTHROUGH */
  88     case dolit:         /* 'do' */
  89     case forstmt:               /* for (...) */
  90         ps.p_stack[++ps.tos] = tk;
  91         ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
  92         ++ps.i_l_follow;        /* subsequent statements should be indented 1 */
  93         ps.search_brace = btype_2;
  94         break;
  95
  96     case lbrace:                /* scanned { */
  97         break_comma = false;    /* don't break comma in an initial list */
  98         if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
  99                 || ps.p_stack[ps.tos] == stmtl)
 100             ++ps.i_l_follow;    /* it is a random, isolated stmt group or a
 101                                  * declaration */
 102         else {
 103             if (s_code == e_code) {
 104                 /*
 105                  * only do this if there is nothing on the line
 106                  */
 107                 --ps.ind_level;
 108                 /*
 109                  * it is a group as part of a while, for, etc.
 110                  */
 111                 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
 112                     --ps.ind_level;
 113                 /*
 114                  * for a switch, brace should be two levels out from the code
 115                  */
 116             }
 117         }
 118
 119         ps.p_stack[++ps.tos] = lbrace;
 120         ps.il[ps.tos] = ps.ind_level;
 121         ps.p_stack[++ps.tos] = stmt;
 122         /* allow null stmt between braces */
 123         ps.il[ps.tos] = ps.i_l_follow;
 124         break;
 125
 126     case whilestmt:             /* scanned while (...) */
 127         if (ps.p_stack[ps.tos] == dohead) {
 128             /* it is matched with do stmt */
 129             ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
 130             ps.p_stack[++ps.tos] = whilestmt;
 131             ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 132         }
 133         else {                  /* it is a while loop */
 134             ps.p_stack[++ps.tos] = whilestmt;
 135             ps.il[ps.tos] = ps.i_l_follow;
 136             ++ps.i_l_follow;
 137             ps.search_brace = btype_2;
 138         }
 139
 140         break;
 141
 142     case elselit:               /* scanned an else */
 143
 144         if (ps.p_stack[ps.tos] != ifhead)
 145             diag2(1, "Unmatched 'else'");
 146         else {
 147             ps.ind_level = ps.il[ps.tos];       /* indentation for else should
 148                                                  * be same as for if */
 149             ps.i_l_follow = ps.ind_level + 1;   /* everything following should
 150                                                  * be in 1 level */
 151             ps.p_stack[ps.tos] = elsehead;
 152             /* remember if with else */
 153             ps.search_brace = btype_2 | ps.else_if;
 154         }
 155         break;
 156
 157     case rbrace:                /* scanned a } */
 158         /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
 159         if (ps.p_stack[ps.tos - 1] == lbrace) {
 160             ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
 161             ps.p_stack[ps.tos] = stmt;
 162         }
 163         else
 164             diag2(1, "Statement nesting error");
 165         break;
 166
 167     case swstmt:                /* had switch (...) */
 168         ps.p_stack[++ps.tos] = swstmt;
 169         ps.cstk[ps.tos] = case_ind;
 170         /* save current case indent level */
 171         ps.il[ps.tos] = ps.i_l_follow;
 172         case_ind = ps.i_l_follow + ps.case_indent;      /* cases should be one
 173                                                          * level down from
 174                                                          * switch */
 175         ps.i_l_follow += ps.case_indent + 1;    /* statements should be two
 176                                                  * levels in */
 177         ps.search_brace = btype_2;
 178         break;
 179
 180     case semicolon:             /* this indicates a simple stmt */
 181         break_comma = false;    /* turn off flag to break after commas in a
 182                                  * declaration */
 183         ps.p_stack[++ps.tos] = stmt;
 184         ps.il[ps.tos] = ps.ind_level;
 185         break;
 186
 187     default:                    /* this is an error */
 188         diag2(1, "Unknown code to parser");
 189         return;
 190
 191
 192     }                           /* end of switch */
 193
 194     reduce();                   /* see if any reduction can be done */
 195
 196 #ifdef debug
 197     for (i = 1; i <= ps.tos; ++i)
 198         printf("(%d %d)", ps.p_stack[i], ps.il[i]);
 199     printf("\n");
 200 #endif
 201
 202     return;
 203 }
 204
 205 /*
 206  * NAME: reduce
 207  *
 208  * FUNCTION: Implements the reduce part of the parsing algorithm
 209  *
 210  * ALGORITHM: The following reductions are done.  Reductions are repeated
 211  *      until no more are possible.
 212  *
 213  * Old TOS              New TOS
 214  * <stmt> <stmt>        <stmtl>
 215  * <stmtl> <stmt>       <stmtl>
 216  * do <stmt>            "dostmt"
 217  * if <stmt>            "ifstmt"
 218  * switch <stmt>        <stmt>
 219  * decl <stmt>          <stmt>
 220  * "ifelse" <stmt>      <stmt>
 221  * for <stmt>           <stmt>
 222  * while <stmt>         <stmt>
 223  * "dostmt" while       <stmt>
 224  *
 225  * On each reduction, ps.i_l_follow (the indentation for the following line)
 226  * is set to the indentation level associated with the old TOS.
 227  *
 228  * PARAMETERS: None
 229  *
 230  * RETURNS: Nothing
 231  *
 232  * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
 233  *
 234  * CALLS: None
 235  *
 236  * CALLED BY: parse
 237  *
 238  * HISTORY: initial coding      November 1976   D A Willcox of CAC
 239  *
 240  */
 241 /*----------------------------------------------*\
 242 |   REDUCTION PHASE                                 |
 243 \*----------------------------------------------*/
 244 static void
 245 reduce(void)
 246 {
 247     int i;
 248
 249     for (;;) {                  /* keep looping until there is nothing left to
 250                                  * reduce */
 251
 252         switch (ps.p_stack[ps.tos]) {
 253
 254         case stmt:
 255             switch (ps.p_stack[ps.tos - 1]) {
 256
 257             case stmt:
 258             case stmtl:
 259                 /* stmtl stmt or stmt stmt */
 260                 ps.p_stack[--ps.tos] = stmtl;
 261                 break;
 262
 263             case dolit: /* <do> <stmt> */
 264                 ps.p_stack[--ps.tos] = dohead;
 265                 ps.i_l_follow = ps.il[ps.tos];
 266                 break;
 267
 268             case ifstmt:
 269                 /* <if> <stmt> */
 270                 ps.p_stack[--ps.tos] = ifhead;
 271                 for (i = ps.tos - 1;
 272                         (
 273                          ps.p_stack[i] != stmt
 274                          &&
 275                          ps.p_stack[i] != stmtl
 276                          &&
 277                          ps.p_stack[i] != lbrace
 278                          );
 279                         --i);
 280                 ps.i_l_follow = ps.il[i];
 281                 /*
 282                  * for the time being, we will assume that there is no else on
 283                  * this if, and set the indentation level accordingly. If an
 284                  * else is scanned, it will be fixed up later
 285                  */
 286                 break;
 287
 288             case swstmt:
 289                 /* <switch> <stmt> */
 290                 case_ind = ps.cstk[ps.tos - 1];
 291                 /* FALLTHROUGH */
 292             case decl:          /* finish of a declaration */
 293             case elsehead:
 294                 /* <<if> <stmt> else> <stmt> */
 295             case forstmt:
 296                 /* <for> <stmt> */
 297             case whilestmt:
 298                 /* <while> <stmt> */
 299                 ps.p_stack[--ps.tos] = stmt;
 300                 ps.i_l_follow = ps.il[ps.tos];
 301                 break;
 302
 303             default:            /* <anything else> <stmt> */
 304                 return;
 305
 306             }                   /* end of section for <stmt> on top of stack */
 307             break;
 308
 309         case whilestmt: /* while (...) on top */
 310             if (ps.p_stack[ps.tos - 1] == dohead) {
 311                 /* it is termination of a do while */
 312                 ps.tos -= 2;
 313                 break;
 314             }
 315             else
 316                 return;
 317
 318         default:                /* anything else on top */
 319             return;
 320
 321         }
 322     }
 323 }