usr.bin/window/parser1.c

   1 /*      @(#)parser1.c   8.1 (Berkeley) 6/6/93   */
   2 /*      $NetBSD: parser1.c,v 1.6 2003/08/07 11:17:28 agc Exp $  */
   3
   4 /*
   5  * Copyright (c) 1983, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * Edward Wang at The University of California, Berkeley.
  10  *
  11  * Redistribution and use in source and binary forms, with or without
  12  * modification, are permitted provided that the following conditions
  13  * are met:
  14  * 1. Redistributions of source code must retain the above copyright
  15  *    notice, this list of conditions and the following disclaimer.
  16  * 2. Redistributions in binary form must reproduce the above copyright
  17  *    notice, this list of conditions and the following disclaimer in the
  18  *    documentation and/or other materials provided with the distribution.
  19  * 3. 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 #include "defs.h"
  37 #include "parser.h"
  38
  39 void
  40 p_start(void)
  41 {
  42         char flag = 1;
  43
  44         (void) s_gettok();
  45         for (;;) {
  46                 p_statementlist(flag);
  47                 if (token == T_EOF || p_abort())
  48                         break;
  49                 flag = 0;
  50                 p_synerror();
  51                 while (token != T_EOL && token != T_EOF) {
  52                         if (token == T_STR)
  53                                 str_free(token_str);
  54                         (void) s_gettok();
  55                 }
  56                 if (token == T_EOL)
  57                         (void) s_gettok();
  58                 p_clearerr();
  59         }
  60 }
  61
  62 void
  63 p_statementlist(char flag)
  64 {
  65         for (; p_statement(flag) >= 0; p_clearerr())
  66                 ;
  67 }
  68
  69 int
  70 p_statement(char flag)
  71 {
  72         switch (token) {
  73         case T_EOL:
  74                 (void) s_gettok();
  75                 return 0;
  76         case T_IF:
  77                 return p_if(flag);
  78         default:
  79                 return p_expression(flag);
  80         }
  81 }
  82
  83 int
  84 p_if(char flag)
  85 {
  86         struct value t;
  87         char true = 0;
  88
  89 top:
  90         (void) s_gettok();
  91
  92         if (p_expr(&t, flag) < 0) {
  93                 p_synerror();
  94                 return -1;
  95         }
  96         switch (t.v_type) {
  97         case V_NUM:
  98                 true = !true && t.v_num != 0;
  99                 break;
 100         case V_STR:
 101                 p_error("if: Numeric value required.");
 102                 str_free(t.v_str);
 103                 /* FALLTHROUGH */
 104         case V_ERR:
 105                 flag = 0;
 106                 break;
 107         }
 108
 109         if (token != T_THEN) {
 110                 p_synerror();
 111                 return -1;
 112         }
 113
 114         (void) s_gettok();
 115         p_statementlist(flag && true);
 116         if (p_erred())
 117                 return -1;
 118
 119         if (token == T_ELSIF)
 120                 goto top;
 121
 122         if (token == T_ELSE) {
 123                 (void) s_gettok();
 124                 p_statementlist(flag && !true);
 125                 if (p_erred())
 126                         return -1;
 127         }
 128
 129         if (token == T_ENDIF) {
 130                 (void) s_gettok();
 131                 return 0;
 132         }
 133
 134         p_synerror();
 135         return -1;
 136 }
 137
 138 int
 139 p_expression(char flag)
 140 {
 141         struct value t;
 142         char *cmd;
 143
 144         switch (token) {
 145         case T_NUM:
 146                 t.v_type = V_NUM;
 147                 t.v_num = token_num;
 148                 (void) s_gettok();
 149                 break;
 150         case T_STR:
 151                 t.v_type = V_STR;
 152                 t.v_str = token_str;
 153                 (void) s_gettok();
 154                 break;
 155         default:
 156                 if (p_expr(&t, flag) < 0)
 157                         return -1;
 158                 if (token == T_EOF) {
 159                         val_free(t);
 160                         return 0;
 161                 }
 162         }
 163         if (token != T_ASSIGN && p_convstr(&t) < 0)
 164                 return -1;
 165         cmd = t.v_type == V_STR ? t.v_str : 0;
 166         if ((*(token == T_ASSIGN ? p_assign : p_function))(cmd, &t, flag) < 0) {
 167                 if (cmd)
 168                         str_free(cmd);
 169                 return -1;
 170         }
 171         if (cmd)
 172                 str_free(cmd);
 173         val_free(t);
 174         if (token == T_EOL)
 175                 (void) s_gettok();
 176         else if (token != T_EOF) {
 177                 p_synerror();
 178                 return -1;
 179         }
 180         return 0;
 181 }
 182
 183 int
 184 p_convstr(struct value *v)
 185 {
 186         if (v->v_type != V_NUM)
 187                 return 0;
 188         if ((v->v_str = str_itoa(v->v_num)) == 0) {
 189                 p_memerror();
 190                 v->v_type = V_ERR;
 191                 return -1;
 192         }
 193         v->v_type = V_STR;
 194         return 0;
 195 }
 196
 197 void
 198 p_synerror(void)
 199 {
 200         if (!cx.x_synerred) {
 201                 cx.x_synerred = cx.x_erred = 1;
 202                 error("Syntax error.");
 203         }
 204 }
 205
 206 void
 207 p_error(const char *msg, ...)
 208 {
 209         va_list ap;
 210
 211         va_start(ap, msg);
 212         if (!cx.x_erred) {
 213                 cx.x_erred = 1;
 214                 verror(msg, ap);
 215         }
 216         va_end(ap);
 217 }
 218
 219 void
 220 p_memerror(void)
 221 {
 222         cx.x_erred = cx.x_abort = 1;
 223         error("Out of memory.");
 224 }