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         case V_ERR:
 104                 flag = 0;
 105                 break;
 106         }
 107
 108         if (token != T_THEN) {
 109                 p_synerror();
 110                 return -1;
 111         }
 112
 113         (void) s_gettok();
 114         p_statementlist(flag && true);
 115         if (p_erred())
 116                 return -1;
 117
 118         if (token == T_ELSIF)
 119                 goto top;
 120
 121         if (token == T_ELSE) {
 122                 (void) s_gettok();
 123                 p_statementlist(flag && !true);
 124                 if (p_erred())
 125                         return -1;
 126         }
 127
 128         if (token == T_ENDIF) {
 129                 (void) s_gettok();
 130                 return 0;
 131         }
 132
 133         p_synerror();
 134         return -1;
 135 }
 136
 137 int
 138 p_expression(char flag)
 139 {
 140         struct value t;
 141         char *cmd;
 142
 143         switch (token) {
 144         case T_NUM:
 145                 t.v_type = V_NUM;
 146                 t.v_num = token_num;
 147                 (void) s_gettok();
 148                 break;
 149         case T_STR:
 150                 t.v_type = V_STR;
 151                 t.v_str = token_str;
 152                 (void) s_gettok();
 153                 break;
 154         default:
 155                 if (p_expr(&t, flag) < 0)
 156                         return -1;
 157                 if (token == T_EOF) {
 158                         val_free(t);
 159                         return 0;
 160                 }
 161         }
 162         if (token != T_ASSIGN && p_convstr(&t) < 0)
 163                 return -1;
 164         cmd = t.v_type == V_STR ? t.v_str : 0;
 165         if ((*(token == T_ASSIGN ? p_assign : p_function))(cmd, &t, flag) < 0) {
 166                 if (cmd)
 167                         str_free(cmd);
 168                 return -1;
 169         }
 170         if (cmd)
 171                 str_free(cmd);
 172         val_free(t);
 173         if (token == T_EOL)
 174                 (void) s_gettok();
 175         else if (token != T_EOF) {
 176                 p_synerror();
 177                 return -1;
 178         }
 179         return 0;
 180 }
 181
 182 int
 183 p_convstr(struct value *v)
 184 {
 185         if (v->v_type != V_NUM)
 186                 return 0;
 187         if ((v->v_str = str_itoa(v->v_num)) == 0) {
 188                 p_memerror();
 189                 v->v_type = V_ERR;
 190                 return -1;
 191         }
 192         v->v_type = V_STR;
 193         return 0;
 194 }
 195
 196 void
 197 p_synerror(void)
 198 {
 199         if (!cx.x_synerred) {
 200                 cx.x_synerred = cx.x_erred = 1;
 201                 error("Syntax error.");
 202         }
 203 }
 204
 205 void
 206 p_error(const char *msg, ...)
 207 {
 208         va_list ap;
 209
 210         va_start(ap, msg);
 211         if (!cx.x_erred) {
 212                 cx.x_erred = 1;
 213                 verror(msg, ap);
 214         }
 215         va_end(ap);
 216 }
 217
 218 void
 219 p_memerror(void)
 220 {
 221         cx.x_erred = cx.x_abort = 1;
 222         error("Out of memory.");
 223 }