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 * Definitions for bc's parser. 33 * 34 */ 35 36 #ifndef BC_PARSE_H 37 #define BC_PARSE_H 38 39 #include <limits.h> 40 #include <stdbool.h> 41 #include <stdint.h> 42 43 #include <status.h> 44 #include <vector.h> 45 #include <lex.h> 46 #include <lang.h> 47 48 // The following are flags that can be passed to @a BcParseExpr functions. They 49 // define the requirements that the parsed expression must meet to not have an 50 // error thrown. 51 52 /// A flag that requires that the expression is valid for conditionals in for 53 /// loops, while loops, and if statements. This is because POSIX requires that 54 /// certain operators are *only* used in those cases. It's whacked, but that's 55 /// how it is. 56 #define BC_PARSE_REL (UINTMAX_C(1) << 0) 57 58 /// A flag that requires that the expression is valid for a print statement. 59 #define BC_PARSE_PRINT (UINTMAX_C(1) << 1) 60 61 /// A flag that requires that the expression does *not* have any function call. 62 #define BC_PARSE_NOCALL (UINTMAX_C(1) << 2) 63 64 /// A flag that requires that the expression does *not* have a read() 65 /// expression. 66 #define BC_PARSE_NOREAD (UINTMAX_C(1) << 3) 67 68 /// A flag that *allows* (rather than requires) that an array appear in the 69 /// expression. This is mostly used as parameters in bc. 70 #define BC_PARSE_ARRAY (UINTMAX_C(1) << 4) 71 72 /// A flag that requires that the expression is not empty and returns a value. 73 #define BC_PARSE_NEEDVAL (UINTMAX_C(1) << 5) 74 75 /** 76 * Returns true if the parser has been initialized. 77 * @param p The parser. 78 * @param prg The program. 79 * @return True if @a p has been initialized, false otherwise. 80 */ 81 #define BC_PARSE_IS_INITED(p, prg) ((p)->prog == (prg)) 82 83 /** 84 * Returns true if the current parser state allows parsing, false otherwise. 85 * @param p The parser. 86 * @return True if parsing can proceed, false otherwise. 87 */ 88 #define BC_PARSE_CAN_PARSE(p) ((p).l.t != BC_LEX_EOF) 89 90 /** 91 * Pushes the instruction @a i onto the bytecode vector for the current 92 * function. 93 * @param p The parser. 94 * @param i The instruction to push onto the bytecode vector. 95 */ 96 #define bc_parse_push(p, i) (bc_vec_pushByte(&(p)->func->code, (uchar) (i))) 97 98 /** 99 * Pushes an index onto the bytecode vector. For more information, see 100 * @a bc_vec_pushIndex() in src/vector.c and @a bc_program_index() in 101 * src/program.c. 102 * @param p The parser. 103 * @param idx The index to push onto the bytecode vector. 104 */ 105 #define bc_parse_pushIndex(p, idx) (bc_vec_pushIndex(&(p)->func->code, (idx))) 106 107 /** 108 * A convenience macro for throwing errors in parse code. This takes care of 109 * plumbing like passing in the current line the lexer is on. 110 * @param p The parser. 111 * @param e The error. 112 */ 113 #if BC_DEBUG 114 #define bc_parse_err(p, e) \ 115 (bc_vm_handleError((e), __FILE__, __LINE__, (p)->l.line)) 116 #else // BC_DEBUG 117 #define bc_parse_err(p, e) (bc_vm_handleError((e), (p)->l.line)) 118 #endif // BC_DEBUG 119 120 /** 121 * A convenience macro for throwing errors in parse code. This takes care of 122 * plumbing like passing in the current line the lexer is on. 123 * @param p The parser. 124 * @param e The error. 125 * @param ... The varags that are needed. 126 */ 127 #if BC_DEBUG 128 #define bc_parse_verr(p, e, ...) \ 129 (bc_vm_handleError((e), __FILE__, __LINE__, (p)->l.line, __VA_ARGS__)) 130 #else // BC_DEBUG 131 #define bc_parse_verr(p, e, ...) \ 132 (bc_vm_handleError((e), (p)->l.line, __VA_ARGS__)) 133 #endif // BC_DEBUG 134 135 // Forward declarations. 136 struct BcParse; 137 struct BcProgram; 138 139 /** 140 * A function pointer to call when more parsing is needed. 141 * @param p The parser. 142 */ 143 typedef void (*BcParseParse)(struct BcParse* p); 144 145 /** 146 * A function pointer to call when an expression needs to be parsed. This can 147 * happen for read() expressions or dc strings. 148 * @param p The parser. 149 * @param flags The flags for what is allowed or required. (See flags above.) 150 */ 151 typedef void (*BcParseExpr)(struct BcParse* p, uint8_t flags); 152 153 /// The parser struct. 154 typedef struct BcParse 155 { 156 /// The lexer. 157 BcLex l; 158 159 #if BC_ENABLED 160 /// The stack of flags for bc. (See comments in include/bc.h.) This stack is 161 /// *required* to have one item at all times. Not maintaining that invariant 162 /// will cause problems. 163 BcVec flags; 164 165 /// The stack of exits. These are indices into the bytecode vector where 166 /// blocks for loops and if statements end. Basically, these are the places 167 /// to jump to when skipping code. 168 BcVec exits; 169 170 /// The stack of conditionals. Unlike exits, which are indices to jump 171 /// *forward* to, this is a vector of indices to jump *backward* to, usually 172 /// to the conditional of a loop, hence the name. 173 BcVec conds; 174 175 /// A stack of operators. When parsing expressions, the bc parser uses the 176 /// Shunting-Yard algorithm, which requires a stack of operators. This can 177 /// hold the stack for multiple expressions at once because the expressions 178 /// stack as well. For more information, see the Expression Parsing section 179 /// of the Development manual (manuals/development.md). 180 BcVec ops; 181 182 /// A buffer to temporarily store a string in. This is because the lexer 183 /// might generate a string as part of its work, and the parser needs that 184 /// string, but it also needs the lexer to continue lexing, which might 185 /// overwrite the string stored in the lexer. This buffer is for copying 186 /// that string from the lexer to keep it safe. 187 BcVec buf; 188 #endif // BC_ENABLED 189 190 /// A reference to the program to grab the current function when necessary. 191 struct BcProgram* prog; 192 193 /// A reference to the current function. The function is what holds the 194 /// bytecode vector that the parser is filling. 195 BcFunc* func; 196 197 /// The index of the function. 198 size_t fidx; 199 200 #if BC_ENABLED 201 /// True if the bc parser just entered a function and an auto statement 202 /// would be valid. 203 bool auto_part; 204 #endif // BC_ENABLED 205 206 } BcParse; 207 208 /** 209 * Initializes a parser. 210 * @param p The parser to initialize. 211 * @param prog A referenc to the program. 212 * @param func The index of the current function. 213 */ 214 void 215 bc_parse_init(BcParse* p, struct BcProgram* prog, size_t func); 216 217 /** 218 * Frees a parser. This is not guarded by #if BC_DEBUG because a separate 219 * parser is created at runtime to parse read() expressions and dc strings. 220 * @param p The parser to free. 221 */ 222 void 223 bc_parse_free(BcParse* p); 224 225 /** 226 * Resets the parser. Resetting means erasing all state to the point that the 227 * parser would think it was just initialized. 228 * @param p The parser to reset. 229 */ 230 void 231 bc_parse_reset(BcParse* p); 232 233 /** 234 * Adds a string. See @a BcProgram in include/program.h for more details. 235 * @param p The parser that parsed the string. 236 */ 237 void 238 bc_parse_addString(BcParse* p); 239 240 /** 241 * Adds a number. See @a BcProgram in include/program.h for more details. 242 * @param p The parser that parsed the number. 243 */ 244 void 245 bc_parse_number(BcParse* p); 246 247 /** 248 * Update the current function in the parser. 249 * @param p The parser. 250 * @param fidx The index of the new function. 251 */ 252 void 253 bc_parse_updateFunc(BcParse* p, size_t fidx); 254 255 /** 256 * Adds a new variable or array. See @a BcProgram in include/program.h for more 257 * details. 258 * @param p The parser that parsed the variable or array name. 259 * @param name The name of the variable or array to add. 260 * @param var True if the name is for a variable, false if it's for an array. 261 */ 262 void 263 bc_parse_pushName(const BcParse* p, char* name, bool var); 264 265 /** 266 * Sets the text that the parser will parse. 267 * @param p The parser. 268 * @param text The text to lex. 269 * @param mode The mode to parse in. 270 */ 271 void 272 bc_parse_text(BcParse* p, const char* text, BcMode mode); 273 274 // References to const 0 and 1 strings for special cases. bc and dc have 275 // specific instructions for 0 and 1 because they pop up so often and (in the 276 // case of 1), increment/decrement operators. 277 extern const char bc_parse_zero[2]; 278 extern const char bc_parse_one[2]; 279 280 #endif // BC_PARSE_H 281