| 1 | /* |
| 2 | * Copyright (c) 1983 Regents of the University of California. |
| 3 | * All rights reserved. |
| 4 | * |
| 5 | * This code is derived from software contributed to Berkeley by |
| 6 | * Edward Wang at The University of California, Berkeley. |
| 7 | * |
| 8 | * Redistribution and use in source and binary forms, with or without |
| 9 | * modification, are permitted provided that the following conditions |
| 10 | * are met: |
| 11 | * 1. Redistributions of source code must retain the above copyright |
| 12 | * notice, this list of conditions and the following disclaimer. |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer in the |
| 15 | * documentation and/or other materials provided with the distribution. |
| 16 | * 3. All advertising materials mentioning features or use of this software |
| 17 | * must display the following acknowledgement: |
| 18 | * This product includes software developed by the University of |
| 19 | * California, Berkeley and its contributors. |
| 20 | * 4. Neither the name of the University nor the names of its contributors |
| 21 | * may be used to endorse or promote products derived from this software |
| 22 | * without specific prior written permission. |
| 23 | * |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 34 | * SUCH DAMAGE. |
| 35 | */ |
| 36 | |
| 37 | #ifndef lint |
| 38 | static char sccsid[] = "@(#)parser1.c 3.22 (Berkeley) 6/6/90"; |
| 39 | #endif /* not lint */ |
| 40 | |
| 41 | #include "parser.h" |
| 42 | |
| 43 | p_start() |
| 44 | { |
| 45 | char flag = 1; |
| 46 | |
| 47 | (void) s_gettok(); |
| 48 | for (;;) { |
| 49 | p_statementlist(flag); |
| 50 | if (token == T_EOF || p_abort()) |
| 51 | break; |
| 52 | flag = 0; |
| 53 | p_synerror(); |
| 54 | while (token != T_EOL && token != T_EOF) { |
| 55 | if (token == T_STR) |
| 56 | str_free(token_str); |
| 57 | (void) s_gettok(); |
| 58 | } |
| 59 | if (token == T_EOL) |
| 60 | (void) s_gettok(); |
| 61 | p_clearerr(); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | p_statementlist(flag) |
| 66 | char flag; |
| 67 | { |
| 68 | for (; p_statement(flag) >= 0; p_clearerr()) |
| 69 | ; |
| 70 | } |
| 71 | |
| 72 | p_statement(flag) |
| 73 | char flag; |
| 74 | { |
| 75 | switch (token) { |
| 76 | case T_EOL: |
| 77 | (void) s_gettok(); |
| 78 | return 0; |
| 79 | case T_IF: |
| 80 | return p_if(flag); |
| 81 | default: |
| 82 | return p_expression(flag); |
| 83 | } |
| 84 | } |
| 85 | |
| 86 | p_if(flag) |
| 87 | char flag; |
| 88 | { |
| 89 | struct value t; |
| 90 | char true = 0; |
| 91 | |
| 92 | top: |
| 93 | (void) s_gettok(); |
| 94 | |
| 95 | if (p_expr(&t, flag) < 0) { |
| 96 | p_synerror(); |
| 97 | return -1; |
| 98 | } |
| 99 | switch (t.v_type) { |
| 100 | case V_NUM: |
| 101 | true = !true && t.v_num != 0; |
| 102 | break; |
| 103 | case V_STR: |
| 104 | p_error("if: Numeric value required."); |
| 105 | str_free(t.v_str); |
| 106 | case V_ERR: |
| 107 | flag = 0; |
| 108 | break; |
| 109 | } |
| 110 | |
| 111 | if (token != T_THEN) { |
| 112 | p_synerror(); |
| 113 | return -1; |
| 114 | } |
| 115 | |
| 116 | (void) s_gettok(); |
| 117 | p_statementlist(flag && true); |
| 118 | if (p_erred()) |
| 119 | return -1; |
| 120 | |
| 121 | if (token == T_ELSIF) |
| 122 | goto top; |
| 123 | |
| 124 | if (token == T_ELSE) { |
| 125 | (void) s_gettok(); |
| 126 | p_statementlist(flag && !true); |
| 127 | if (p_erred()) |
| 128 | return -1; |
| 129 | } |
| 130 | |
| 131 | if (token == T_ENDIF) { |
| 132 | (void) s_gettok(); |
| 133 | return 0; |
| 134 | } |
| 135 | |
| 136 | p_synerror(); |
| 137 | return -1; |
| 138 | } |
| 139 | |
| 140 | p_expression(flag) |
| 141 | char flag; |
| 142 | { |
| 143 | struct value t; |
| 144 | char *cmd; |
| 145 | int p_function(), p_assign(); |
| 146 | |
| 147 | switch (token) { |
| 148 | case T_NUM: |
| 149 | t.v_type = V_NUM; |
| 150 | t.v_num = token_num; |
| 151 | (void) s_gettok(); |
| 152 | break; |
| 153 | case T_STR: |
| 154 | t.v_type = V_STR; |
| 155 | t.v_str = token_str; |
| 156 | (void) s_gettok(); |
| 157 | break; |
| 158 | default: |
| 159 | if (p_expr(&t, flag) < 0) |
| 160 | return -1; |
| 161 | if (token == T_EOF) { |
| 162 | val_free(t); |
| 163 | return 0; |
| 164 | } |
| 165 | } |
| 166 | if (token != T_ASSIGN && p_convstr(&t) < 0) |
| 167 | return -1; |
| 168 | cmd = t.v_type == V_STR ? t.v_str : 0; |
| 169 | if ((*(token == T_ASSIGN ? p_assign : p_function))(cmd, &t, flag) < 0) { |
| 170 | if (cmd) |
| 171 | str_free(cmd); |
| 172 | return -1; |
| 173 | } |
| 174 | if (cmd) |
| 175 | str_free(cmd); |
| 176 | val_free(t); |
| 177 | if (token == T_EOL) |
| 178 | (void) s_gettok(); |
| 179 | else if (token != T_EOF) { |
| 180 | p_synerror(); |
| 181 | return -1; |
| 182 | } |
| 183 | return 0; |
| 184 | } |
| 185 | |
| 186 | p_convstr(v) |
| 187 | register struct value *v; |
| 188 | { |
| 189 | if (v->v_type != V_NUM) |
| 190 | return 0; |
| 191 | if ((v->v_str = str_itoa(v->v_num)) == 0) { |
| 192 | p_memerror(); |
| 193 | v->v_type = V_ERR; |
| 194 | return -1; |
| 195 | } |
| 196 | v->v_type = V_STR; |
| 197 | return 0; |
| 198 | } |
| 199 | |
| 200 | p_synerror() |
| 201 | { |
| 202 | if (!cx.x_synerred) { |
| 203 | cx.x_synerred = cx.x_erred = 1; |
| 204 | error("Syntax error."); |
| 205 | } |
| 206 | } |
| 207 | |
| 208 | /*VARARGS1*/ |
| 209 | p_error(msg, a, b, c) |
| 210 | char *msg; |
| 211 | { |
| 212 | if (!cx.x_erred) { |
| 213 | cx.x_erred = 1; |
| 214 | error(msg, a, b, c); |
| 215 | } |
| 216 | } |
| 217 | |
| 218 | p_memerror() |
| 219 | { |
| 220 | cx.x_erred = cx.x_abort = 1; |
| 221 | error("Out of memory."); |
| 222 | } |