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 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->is_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->is_stdin || l->is_exprs)) 145 { 146 got_more = bc_lex_readLine(l); 147 } 148 if (got_more) bc_vec_popAll(&l->str); 149 } 150 } 151 while (got_more && depth); 152 153 // Obviously, if we didn't balance, that's an error. 154 if (BC_ERR(c == '\0' && depth)) 155 { 156 l->i = i; 157 bc_lex_err(l, BC_ERR_PARSE_STRING); 158 } 159 160 bc_vec_pushByte(&l->str, '\0'); 161 162 l->i = i; 163 l->line += nls; 164 } 165 166 /** 167 * Lexes a dc token. This is the dc implementation of BcLexNext. 168 * @param l The lexer. 169 */ 170 void 171 dc_lex_token(BcLex* l) 172 { 173 char c = l->buf[l->i++], c2; 174 size_t i; 175 176 BC_SIG_ASSERT_LOCKED; 177 178 // If the last token was a command that needs a register, we need to parse a 179 // register, so do so. 180 for (i = 0; i < dc_lex_regs_len; ++i) 181 { 182 // If the token is a register token, take care of it and return. 183 if (l->last == dc_lex_regs[i]) 184 { 185 dc_lex_register(l); 186 return; 187 } 188 } 189 190 // These lines are for tokens that easily correspond to one character. We 191 // just set the token. 192 if (c >= '"' && c <= '~' && 193 (l->t = dc_lex_tokens[(c - '"')]) != BC_LEX_INVALID) 194 { 195 return; 196 } 197 198 // This is the workhorse of the lexer when more complicated things are 199 // needed. 200 switch (c) 201 { 202 case '\0': 203 case '\n': 204 case '\t': 205 case '\v': 206 case '\f': 207 case '\r': 208 case ' ': 209 { 210 bc_lex_commonTokens(l, c); 211 break; 212 } 213 214 // We don't have the ! command, so we always expect certain things 215 // after the exclamation point. 216 case '!': 217 { 218 c2 = l->buf[l->i]; 219 220 if (c2 == '=') l->t = BC_LEX_OP_REL_NE; 221 else if (c2 == '<') l->t = BC_LEX_OP_REL_LE; 222 else if (c2 == '>') l->t = BC_LEX_OP_REL_GE; 223 else bc_lex_invalidChar(l, c); 224 225 l->i += 1; 226 227 break; 228 } 229 230 case '#': 231 { 232 bc_lex_lineComment(l); 233 break; 234 } 235 236 case '.': 237 { 238 c2 = l->buf[l->i]; 239 240 // If the character after is a number, this dot is part of a number. 241 // Otherwise, it's the BSD dot (equivalent to last). 242 if (BC_NO_ERR(BC_LEX_NUM_CHAR(c2, true, false))) 243 { 244 bc_lex_number(l, c); 245 } 246 else bc_lex_invalidChar(l, c); 247 248 break; 249 } 250 251 case '0': 252 case '1': 253 case '2': 254 case '3': 255 case '4': 256 case '5': 257 case '6': 258 case '7': 259 case '8': 260 case '9': 261 case 'A': 262 case 'B': 263 case 'C': 264 case 'D': 265 case 'E': 266 case 'F': 267 { 268 bc_lex_number(l, c); 269 break; 270 } 271 272 case 'g': 273 { 274 c2 = l->buf[l->i]; 275 276 if (c2 == 'l') l->t = BC_LEX_KW_LINE_LENGTH; 277 else if (c2 == 'z') l->t = BC_LEX_KW_LEADING_ZERO; 278 else bc_lex_invalidChar(l, c2); 279 280 l->i += 1; 281 282 break; 283 } 284 285 case '[': 286 { 287 dc_lex_string(l); 288 break; 289 } 290 291 default: 292 { 293 bc_lex_invalidChar(l, c); 294 } 295 } 296 } 297 #endif // DC_ENABLED 298