1 /* 2 * ***************************************************************************** 3 * 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (c) 2018-2021 Gavin D. Howard and contributors. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions are met: 10 * 11 * * Redistributions of source code must retain the above copyright notice, this 12 * list of conditions and the following disclaimer. 13 * 14 * * Redistributions in binary form must reproduce the above copyright notice, 15 * this list of conditions and the following disclaimer in the documentation 16 * and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 19 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE 22 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28 * POSSIBILITY OF SUCH DAMAGE. 29 * 30 * ***************************************************************************** 31 * 32 * The lexer for dc. 33 * 34 */ 35 36 #if DC_ENABLED 37 38 #include <ctype.h> 39 40 #include <dc.h> 41 #include <vm.h> 42 43 bool dc_lex_negCommand(BcLex *l) { 44 char c = l->buf[l->i]; 45 return !BC_LEX_NUM_CHAR(c, false, false); 46 } 47 48 /** 49 * Processes a dc command that needs a register. This is where the 50 * extended-register extension is implemented. 51 * @param l The lexer. 52 */ 53 static void dc_lex_register(BcLex *l) { 54 55 // If extended register is enabled and the character is whitespace... 56 if (DC_X && isspace(l->buf[l->i - 1])) { 57 58 char c; 59 60 // Eat the whitespace. 61 bc_lex_whitespace(l); 62 c = l->buf[l->i]; 63 64 // Check for a letter or underscore. 65 if (BC_ERR(!isalpha(c) && c != '_')) 66 bc_lex_verr(l, BC_ERR_PARSE_CHAR, c); 67 68 // Parse a normal identifier. 69 l->i += 1; 70 bc_lex_name(l); 71 } 72 else { 73 74 // I don't allow newlines because newlines are used for controlling when 75 // execution happens, and allowing newlines would just be complex. 76 if (BC_ERR(l->buf[l->i - 1] == '\n')) 77 bc_lex_verr(l, BC_ERR_PARSE_CHAR, l->buf[l->i - 1]); 78 79 // Set the lexer string and token. 80 bc_vec_popAll(&l->str); 81 bc_vec_pushByte(&l->str, (uchar) l->buf[l->i - 1]); 82 bc_vec_pushByte(&l->str, '\0'); 83 l->t = BC_LEX_NAME; 84 } 85 } 86 87 /** 88 * Parses a dc string. Since dc's strings need to check for balanced brackets, 89 * we can't just parse bc and dc strings with different start and end 90 * characters. Oh, and dc strings need to check for escaped brackets. 91 * @param l The lexer. 92 */ 93 static void dc_lex_string(BcLex *l) { 94 95 size_t depth, nls, i; 96 char c; 97 bool got_more; 98 99 // Set the token and clear the string. 100 l->t = BC_LEX_STR; 101 bc_vec_popAll(&l->str); 102 103 do { 104 105 depth = 1; 106 nls = 0; 107 got_more = false; 108 109 assert(!l->is_stdin || l->buf == vm.buffer.v); 110 111 // This is the meat. As long as we don't run into the NUL byte, and we 112 // have "depth", which means we haven't completely balanced brackets 113 // yet, we continue eating the string. 114 for (i = l->i; (c = l->buf[i]) && depth; ++i) { 115 116 // Check for escaped brackets and set the depths as appropriate. 117 if (c == '\\') { 118 c = l->buf[++i]; 119 if (!c) break; 120 } 121 else { 122 depth += (c == '['); 123 depth -= (c == ']'); 124 } 125 126 // We want to adjust the line in the lexer as necessary. 127 nls += (c == '\n'); 128 129 if (depth) bc_vec_push(&l->str, &c); 130 } 131 132 if (BC_ERR(c == '\0' && depth)) { 133 if (!vm.eof && l->is_stdin) got_more = bc_lex_readLine(l); 134 if (got_more) bc_vec_popAll(&l->str); 135 } 136 137 } while (got_more && depth); 138 139 // Obviously, if we didn't balance, that's an error. 140 if (BC_ERR(c == '\0' && depth)) { 141 l->i = i; 142 bc_lex_err(l, BC_ERR_PARSE_STRING); 143 } 144 145 bc_vec_pushByte(&l->str, '\0'); 146 147 l->i = i; 148 l->line += nls; 149 } 150 151 /** 152 * Lexes a dc token. This is the dc implementation of BcLexNext. 153 * @param l The lexer. 154 */ 155 void dc_lex_token(BcLex *l) { 156 157 char c = l->buf[l->i++], c2; 158 size_t i; 159 160 // If the last token was a command that needs a register, we need to parse a 161 // register, so do so. 162 for (i = 0; i < dc_lex_regs_len; ++i) { 163 164 // If the token is a register token, take care of it and return. 165 if (l->last == dc_lex_regs[i]) { 166 dc_lex_register(l); 167 return; 168 } 169 } 170 171 // These lines are for tokens that easily correspond to one character. We 172 // just set the token. 173 if (c >= '"' && c <= '~' && 174 (l->t = dc_lex_tokens[(c - '"')]) != BC_LEX_INVALID) 175 { 176 return; 177 } 178 179 // This is the workhorse of the lexer when more complicated things are 180 // needed. 181 switch (c) { 182 183 case '\0': 184 case '\n': 185 case '\t': 186 case '\v': 187 case '\f': 188 case '\r': 189 case ' ': 190 { 191 bc_lex_commonTokens(l, c); 192 break; 193 } 194 195 // We don't have the ! command, so we always expect certain things 196 // after the exclamation point. 197 case '!': 198 { 199 c2 = l->buf[l->i]; 200 201 if (c2 == '=') l->t = BC_LEX_OP_REL_NE; 202 else if (c2 == '<') l->t = BC_LEX_OP_REL_LE; 203 else if (c2 == '>') l->t = BC_LEX_OP_REL_GE; 204 else bc_lex_invalidChar(l, c); 205 206 l->i += 1; 207 208 break; 209 } 210 211 case '#': 212 { 213 bc_lex_lineComment(l); 214 break; 215 } 216 217 case '.': 218 { 219 c2 = l->buf[l->i]; 220 221 // If the character after is a number, this dot is part of a number. 222 // Otherwise, it's the BSD dot (equivalent to last). 223 if (BC_NO_ERR(BC_LEX_NUM_CHAR(c2, true, false))) 224 bc_lex_number(l, c); 225 else bc_lex_invalidChar(l, c); 226 227 break; 228 } 229 230 case '0': 231 case '1': 232 case '2': 233 case '3': 234 case '4': 235 case '5': 236 case '6': 237 case '7': 238 case '8': 239 case '9': 240 case 'A': 241 case 'B': 242 case 'C': 243 case 'D': 244 case 'E': 245 case 'F': 246 { 247 bc_lex_number(l, c); 248 break; 249 } 250 251 case 'g': 252 { 253 c2 = l->buf[l->i]; 254 255 if (c2 == 'l') l->t = BC_LEX_KW_LINE_LENGTH; 256 else if (c2 == 'z') l->t = BC_LEX_KW_LEADING_ZERO; 257 else bc_lex_invalidChar(l, c2); 258 259 l->i += 1; 260 261 break; 262 } 263 264 case '[': 265 { 266 dc_lex_string(l); 267 break; 268 } 269 270 default: 271 { 272 bc_lex_invalidChar(l, c); 273 } 274 } 275 } 276 #endif // DC_ENABLED 277