1 /* 2 * ***************************************************************************** 3 * 4 * SPDX-License-Identifier: BSD-2-Clause 5 * 6 * Copyright (c) 2018-2023 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 44 dc_lex_negCommand(BcLex* l) 45 { 46 char c = l->buf[l->i]; 47 return !BC_LEX_NUM_CHAR(c, false, false); 48 } 49 50 /** 51 * Processes a dc command that needs a register. This is where the 52 * extended-register extension is implemented. 53 * @param l The lexer. 54 */ 55 static void 56 dc_lex_register(BcLex* l) 57 { 58 // If extended register is enabled and the character is whitespace... 59 if (DC_X && isspace(l->buf[l->i - 1])) 60 { 61 char c; 62 63 // Eat the whitespace. 64 bc_lex_whitespace(l); 65 c = l->buf[l->i]; 66 67 // Check for a letter or underscore. 68 if (BC_ERR(!isalpha(c) && c != '_')) 69 { 70 bc_lex_verr(l, BC_ERR_PARSE_CHAR, c); 71 } 72 73 // Parse a normal identifier. 74 l->i += 1; 75 bc_lex_name(l); 76 } 77 else 78 { 79 // I don't allow newlines because newlines are used for controlling when 80 // execution happens, and allowing newlines would just be complex. 81 if (BC_ERR(l->buf[l->i - 1] == '\n')) 82 { 83 bc_lex_verr(l, BC_ERR_PARSE_CHAR, l->buf[l->i - 1]); 84 } 85 86 // Set the lexer string and token. 87 bc_vec_popAll(&l->str); 88 bc_vec_pushByte(&l->str, (uchar) l->buf[l->i - 1]); 89 bc_vec_pushByte(&l->str, '\0'); 90 l->t = BC_LEX_NAME; 91 } 92 } 93 94 /** 95 * Parses a dc string. Since dc's strings need to check for balanced brackets, 96 * we can't just parse bc and dc strings with different start and end 97 * characters. Oh, and dc strings need to check for escaped brackets. 98 * @param l The lexer. 99 */ 100 static void 101 dc_lex_string(BcLex* l) 102 { 103 size_t depth, nls, i; 104 char c; 105 bool got_more; 106 107 // Set the token and clear the string. 108 l->t = BC_LEX_STR; 109 bc_vec_popAll(&l->str); 110 111 do 112 { 113 depth = 1; 114 nls = 0; 115 got_more = false; 116 117 assert(l->mode != BC_MODE_STDIN || l->buf == vm->buffer.v); 118 119 // This is the meat. As long as we don't run into the NUL byte, and we 120 // have "depth", which means we haven't completely balanced brackets 121 // yet, we continue eating the string. 122 for (i = l->i; (c = l->buf[i]) && depth; ++i) 123 { 124 // Check for escaped brackets and set the depths as appropriate. 125 if (c == '\\') 126 { 127 c = l->buf[++i]; 128 if (!c) break; 129 } 130 else 131 { 132 depth += (c == '['); 133 depth -= (c == ']'); 134 } 135 136 // We want to adjust the line in the lexer as necessary. 137 nls += (c == '\n'); 138 139 if (depth) bc_vec_push(&l->str, &c); 140 } 141 142 if (BC_ERR(c == '\0' && depth)) 143 { 144 if (!vm->eof && l->mode != BC_MODE_FILE) 145 { 146 got_more = bc_lex_readLine(l); 147 } 148 149 if (got_more) 150 { 151 bc_vec_popAll(&l->str); 152 } 153 } 154 } 155 while (got_more && depth); 156 157 // Obviously, if we didn't balance, that's an error. 158 if (BC_ERR(c == '\0' && depth)) 159 { 160 l->i = i; 161 bc_lex_err(l, BC_ERR_PARSE_STRING); 162 } 163 164 bc_vec_pushByte(&l->str, '\0'); 165 166 l->i = i; 167 l->line += nls; 168 } 169 170 /** 171 * Lexes a dc token. This is the dc implementation of BcLexNext. 172 * @param l The lexer. 173 */ 174 void 175 dc_lex_token(BcLex* l) 176 { 177 char c = l->buf[l->i++], c2; 178 size_t i; 179 180 BC_SIG_ASSERT_LOCKED; 181 182 // If the last token was a command that needs a register, we need to parse a 183 // register, so do so. 184 for (i = 0; i < dc_lex_regs_len; ++i) 185 { 186 // If the token is a register token, take care of it and return. 187 if (l->last == dc_lex_regs[i]) 188 { 189 dc_lex_register(l); 190 return; 191 } 192 } 193 194 // These lines are for tokens that easily correspond to one character. We 195 // just set the token. 196 if (c >= '"' && c <= '~' && 197 (l->t = dc_lex_tokens[(c - '"')]) != BC_LEX_INVALID) 198 { 199 return; 200 } 201 202 // This is the workhorse of the lexer when more complicated things are 203 // needed. 204 switch (c) 205 { 206 case '\0': 207 case '\n': 208 case '\t': 209 case '\v': 210 case '\f': 211 case '\r': 212 case ' ': 213 { 214 bc_lex_commonTokens(l, c); 215 break; 216 } 217 218 // We don't have the ! command, so we always expect certain things 219 // after the exclamation point. 220 case '!': 221 { 222 c2 = l->buf[l->i]; 223 224 if (c2 == '=') l->t = BC_LEX_OP_REL_NE; 225 else if (c2 == '<') l->t = BC_LEX_OP_REL_LE; 226 else if (c2 == '>') l->t = BC_LEX_OP_REL_GE; 227 else bc_lex_invalidChar(l, c); 228 229 l->i += 1; 230 231 break; 232 } 233 234 case '#': 235 { 236 bc_lex_lineComment(l); 237 break; 238 } 239 240 case '.': 241 { 242 c2 = l->buf[l->i]; 243 244 // If the character after is a number, this dot is part of a number. 245 // Otherwise, it's the BSD dot (equivalent to last). 246 if (BC_NO_ERR(BC_LEX_NUM_CHAR(c2, true, false))) 247 { 248 bc_lex_number(l, c); 249 } 250 else bc_lex_invalidChar(l, c); 251 252 break; 253 } 254 255 case '0': 256 case '1': 257 case '2': 258 case '3': 259 case '4': 260 case '5': 261 case '6': 262 case '7': 263 case '8': 264 case '9': 265 case 'A': 266 case 'B': 267 case 'C': 268 case 'D': 269 case 'E': 270 case 'F': 271 { 272 bc_lex_number(l, c); 273 break; 274 } 275 276 case 'g': 277 { 278 c2 = l->buf[l->i]; 279 280 if (c2 == 'l') l->t = BC_LEX_KW_LINE_LENGTH; 281 else if (c2 == 'x') l->t = BC_LEX_EXTENDED_REGISTERS; 282 else if (c2 == 'z') l->t = BC_LEX_KW_LEADING_ZERO; 283 else bc_lex_invalidChar(l, c2); 284 285 l->i += 1; 286 287 break; 288 } 289 290 case '[': 291 { 292 dc_lex_string(l); 293 break; 294 } 295 296 default: 297 { 298 bc_lex_invalidChar(l, c); 299 } 300 } 301 } 302 #endif // DC_ENABLED 303