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