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 <stdio.h>
  46 #include "indent_globs.h"
  47 #include "indent_codes.h"
  48 #include "indent.h"
  49
  50 static void reduce(void);
  51
  52 void
  53 parse(int tk) /* tk: the code for the construct scanned */
  54 {
  55     int         i;
  56
  57 #ifdef debug
  58     printf("%2d - %s\n", tk, token);
  59 #endif
  60
  61     while (ps.p_stack[ps.tos] == ifhead && tk != elselit) {
  62         /* true if we have an if without an else */
  63         ps.p_stack[ps.tos] = stmt;      /* apply the if(..) stmt ::= stmt
  64                                          * reduction */
  65         reduce();               /* see if this allows any reduction */
  66     }
  67
  68
  69     switch (tk) {               /* go on and figure out what to do with the
  70                                  * input */
  71
  72     case decl:                  /* scanned a declaration word */
  73         ps.search_brace = btype_2;
  74         /* indicate that following brace should be on same line */
  75         if (ps.p_stack[ps.tos] != decl) {       /* only put one declaration
  76                                                  * onto stack */
  77             break_comma = true; /* while in declaration, newline should be
  78                                  * forced after comma */
  79             ps.p_stack[++ps.tos] = decl;
  80             ps.il[ps.tos] = ps.i_l_follow;
  81
  82             if (ps.ljust_decl) {/* only do if we want left justified
  83                                  * declarations */
  84                 ps.ind_level = 0;
  85                 for (i = ps.tos - 1; i > 0; --i)
  86                     if (ps.p_stack[i] == decl)
  87                         ++ps.ind_level; /* indentation is number of
  88                                          * declaration levels deep we are */
  89                 ps.i_l_follow = ps.ind_level;
  90             }
  91         }
  92         break;
  93
  94     case ifstmt:                /* scanned if (...) */
  95         if (ps.p_stack[ps.tos] == elsehead && ps.else_if)       /* "else if ..." */
  96             ps.i_l_follow = ps.il[ps.tos];
  97     case dolit:         /* 'do' */
  98     case forstmt:               /* for (...) */
  99         ps.p_stack[++ps.tos] = tk;
 100         ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 101         ++ps.i_l_follow;        /* subsequent statements should be indented 1 */
 102         ps.search_brace = btype_2;
 103         break;
 104
 105     case lbrace:                /* scanned { */
 106         break_comma = false;    /* don't break comma in an initial list */
 107         if (ps.p_stack[ps.tos] == stmt || ps.p_stack[ps.tos] == decl
 108                 || ps.p_stack[ps.tos] == stmtl)
 109             ++ps.i_l_follow;    /* it is a random, isolated stmt group or a
 110                                  * declaration */
 111         else {
 112             if (s_code == e_code) {
 113                 /*
 114                  * only do this if there is nothing on the line
 115                  */
 116                 --ps.ind_level;
 117                 /*
 118                  * it is a group as part of a while, for, etc.
 119                  */
 120                 if (ps.p_stack[ps.tos] == swstmt && ps.case_indent >= 1)
 121                     --ps.ind_level;
 122                 /*
 123                  * for a switch, brace should be two levels out from the code
 124                  */
 125             }
 126         }
 127
 128         ps.p_stack[++ps.tos] = lbrace;
 129         ps.il[ps.tos] = ps.ind_level;
 130         ps.p_stack[++ps.tos] = stmt;
 131         /* allow null stmt between braces */
 132         ps.il[ps.tos] = ps.i_l_follow;
 133         break;
 134
 135     case whilestmt:             /* scanned while (...) */
 136         if (ps.p_stack[ps.tos] == dohead) {
 137             /* it is matched with do stmt */
 138             ps.ind_level = ps.i_l_follow = ps.il[ps.tos];
 139             ps.p_stack[++ps.tos] = whilestmt;
 140             ps.il[ps.tos] = ps.ind_level = ps.i_l_follow;
 141         }
 142         else {                  /* it is a while loop */
 143             ps.p_stack[++ps.tos] = whilestmt;
 144             ps.il[ps.tos] = ps.i_l_follow;
 145             ++ps.i_l_follow;
 146             ps.search_brace = btype_2;
 147         }
 148
 149         break;
 150
 151     case elselit:               /* scanned an else */
 152
 153         if (ps.p_stack[ps.tos] != ifhead)
 154             diag2(1, "Unmatched 'else'");
 155         else {
 156             ps.ind_level = ps.il[ps.tos];       /* indentation for else should
 157                                                  * be same as for if */
 158             ps.i_l_follow = ps.ind_level + 1;   /* everything following should
 159                                                  * be in 1 level */
 160             ps.p_stack[ps.tos] = elsehead;
 161             /* remember if with else */
 162             ps.search_brace = btype_2 | ps.else_if;
 163         }
 164         break;
 165
 166     case rbrace:                /* scanned a } */
 167         /* stack should have <lbrace> <stmt> or <lbrace> <stmtl> */
 168         if (ps.p_stack[ps.tos - 1] == lbrace) {
 169             ps.ind_level = ps.i_l_follow = ps.il[--ps.tos];
 170             ps.p_stack[ps.tos] = stmt;
 171         }
 172         else
 173             diag2(1, "Statement nesting error");
 174         break;
 175
 176     case swstmt:                /* had switch (...) */
 177         ps.p_stack[++ps.tos] = swstmt;
 178         ps.cstk[ps.tos] = case_ind;
 179         /* save current case indent level */
 180         ps.il[ps.tos] = ps.i_l_follow;
 181         case_ind = ps.i_l_follow + ps.case_indent;      /* cases should be one
 182                                                          * level down from
 183                                                          * switch */
 184         ps.i_l_follow += ps.case_indent + 1;    /* statements should be two
 185                                                  * levels in */
 186         ps.search_brace = btype_2;
 187         break;
 188
 189     case semicolon:             /* this indicates a simple stmt */
 190         break_comma = false;    /* turn off flag to break after commas in a
 191                                  * declaration */
 192         ps.p_stack[++ps.tos] = stmt;
 193         ps.il[ps.tos] = ps.ind_level;
 194         break;
 195
 196     default:                    /* this is an error */
 197         diag2(1, "Unknown code to parser");
 198         return;
 199
 200
 201     }                           /* end of switch */
 202
 203     reduce();                   /* see if any reduction can be done */
 204
 205 #ifdef debug
 206     for (i = 1; i <= ps.tos; ++i)
 207         printf("(%d %d)", ps.p_stack[i], ps.il[i]);
 208     printf("\n");
 209 #endif
 210
 211     return;
 212 }
 213
 214 /*
 215  * NAME: reduce
 216  *
 217  * FUNCTION: Implements the reduce part of the parsing algorithm
 218  *
 219  * ALGORITHM: The following reductions are done.  Reductions are repeated
 220  *      until no more are possible.
 221  *
 222  * Old TOS              New TOS
 223  * <stmt> <stmt>        <stmtl>
 224  * <stmtl> <stmt>       <stmtl>
 225  * do <stmt>            "dostmt"
 226  * if <stmt>            "ifstmt"
 227  * switch <stmt>        <stmt>
 228  * decl <stmt>          <stmt>
 229  * "ifelse" <stmt>      <stmt>
 230  * for <stmt>           <stmt>
 231  * while <stmt>         <stmt>
 232  * "dostmt" while       <stmt>
 233  *
 234  * On each reduction, ps.i_l_follow (the indentation for the following line)
 235  * is set to the indentation level associated with the old TOS.
 236  *
 237  * PARAMETERS: None
 238  *
 239  * RETURNS: Nothing
 240  *
 241  * GLOBALS: ps.cstk ps.i_l_follow = ps.il ps.p_stack = ps.tos =
 242  *
 243  * CALLS: None
 244  *
 245  * CALLED BY: parse
 246  *
 247  * HISTORY: initial coding      November 1976   D A Willcox of CAC
 248  *
 249  */
 250 /*----------------------------------------------*\
 251 |   REDUCTION PHASE                                 |
 252 \*----------------------------------------------*/
 253 static void
 254 reduce(void)
 255 {
 256     int i;
 257
 258     for (;;) {                  /* keep looping until there is nothing left to
 259                                  * reduce */
 260
 261         switch (ps.p_stack[ps.tos]) {
 262
 263         case stmt:
 264             switch (ps.p_stack[ps.tos - 1]) {
 265
 266             case stmt:
 267             case stmtl:
 268                 /* stmtl stmt or stmt stmt */
 269                 ps.p_stack[--ps.tos] = stmtl;
 270                 break;
 271
 272             case dolit: /* <do> <stmt> */
 273                 ps.p_stack[--ps.tos] = dohead;
 274                 ps.i_l_follow = ps.il[ps.tos];
 275                 break;
 276
 277             case ifstmt:
 278                 /* <if> <stmt> */
 279                 ps.p_stack[--ps.tos] = ifhead;
 280                 for (i = ps.tos - 1;
 281                         (
 282                          ps.p_stack[i] != stmt
 283                          &&
 284                          ps.p_stack[i] != stmtl
 285                          &&
 286                          ps.p_stack[i] != lbrace
 287                          );
 288                         --i);
 289                 ps.i_l_follow = ps.il[i];
 290                 /*
 291                  * for the time being, we will assume that there is no else on
 292                  * this if, and set the indentation level accordingly. If an
 293                  * else is scanned, it will be fixed up later
 294                  */
 295                 break;
 296
 297             case swstmt:
 298                 /* <switch> <stmt> */
 299                 case_ind = ps.cstk[ps.tos - 1];
 300
 301             case decl:          /* finish of a declaration */
 302             case elsehead:
 303                 /* <<if> <stmt> else> <stmt> */
 304             case forstmt:
 305                 /* <for> <stmt> */
 306             case whilestmt:
 307                 /* <while> <stmt> */
 308                 ps.p_stack[--ps.tos] = stmt;
 309                 ps.i_l_follow = ps.il[ps.tos];
 310                 break;
 311
 312             default:            /* <anything else> <stmt> */
 313                 return;
 314
 315             }                   /* end of section for <stmt> on top of stack */
 316             break;
 317
 318         case whilestmt: /* while (...) on top */
 319             if (ps.p_stack[ps.tos - 1] == dohead) {
 320                 /* it is termination of a do while */
 321                 ps.tos -= 2;
 322                 break;
 323             }
 324             else
 325                 return;
 326
 327         default:                /* anything else on top */
 328             return;
 329
 330         }
 331     }
 332 }