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Diffstat (limited to 'contrib/bc/include/parse.h')
| -rw-r--r-- | contrib/bc/include/parse.h | 275 |
1 files changed, 275 insertions, 0 deletions
diff --git a/contrib/bc/include/parse.h b/contrib/bc/include/parse.h new file mode 100644 index 000000000000..0088c1523ec6 --- /dev/null +++ b/contrib/bc/include/parse.h @@ -0,0 +1,275 @@ +/* + * ***************************************************************************** + * + * SPDX-License-Identifier: BSD-2-Clause + * + * Copyright (c) 2018-2021 Gavin D. Howard and contributors. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, this + * list of conditions and the following disclaimer. + * + * * Redistributions in binary form must reproduce the above copyright notice, + * this list of conditions and the following disclaimer in the documentation + * and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * ***************************************************************************** + * + * Definitions for bc's parser. + * + */ + +#ifndef BC_PARSE_H +#define BC_PARSE_H + +#include <limits.h> +#include <stdbool.h> +#include <stdint.h> + +#include <status.h> +#include <vector.h> +#include <lex.h> +#include <lang.h> + +// The following are flags that can be passed to @a BcParseExpr functions. They +// define the requirements that the parsed expression must meet to not have an +// error thrown. + +/// A flag that requires that the expression is valid for conditionals in for +/// loops, while loops, and if statements. This is because POSIX requires that +/// certain operators are *only* used in those cases. It's whacked, but that's +/// how it is. +#define BC_PARSE_REL (UINTMAX_C(1)<<0) + +/// A flag that requires that the expression is valid for a print statement. +#define BC_PARSE_PRINT (UINTMAX_C(1)<<1) + +/// A flag that requires that the expression does *not* have any function call. +#define BC_PARSE_NOCALL (UINTMAX_C(1)<<2) + +/// A flag that requires that the expression does *not* have a read() expression. +#define BC_PARSE_NOREAD (UINTMAX_C(1)<<3) + +/// A flag that *allows* (rather than requires) that an array appear in the +/// expression. This is mostly used as parameters in bc. +#define BC_PARSE_ARRAY (UINTMAX_C(1)<<4) + +/// A flag that requires that the expression is not empty and returns a value. +#define BC_PARSE_NEEDVAL (UINTMAX_C(1)<<5) + +/** + * Returns true if the parser has been initialized. + * @param p The parser. + * @param prg The program. + * @return True if @a p has been initialized, false otherwise. + */ +#define BC_PARSE_IS_INITED(p, prg) ((p)->prog == (prg)) + +#if BC_ENABLED + +/** + * Returns true if the current parser state allows parsing, false otherwise. + * @param p The parser. + * @return True if parsing can proceed, false otherwise. + */ +#define BC_PARSE_CAN_PARSE(p) \ + ((p).l.t != BC_LEX_EOF && (p).l.t != BC_LEX_KW_DEFINE) + +#else // BC_ENABLED + +/** + * Returns true if the current parser state allows parsing, false otherwise. + * @param p The parser. + * @return True if parsing can proceed, false otherwise. + */ +#define BC_PARSE_CAN_PARSE(p) ((p).l.t != BC_LEX_EOF) + +#endif // BC_ENABLED + +/** + * Pushes the instruction @a i onto the bytecode vector for the current + * function. + * @param p The parser. + * @param i The instruction to push onto the bytecode vector. + */ +#define bc_parse_push(p, i) (bc_vec_pushByte(&(p)->func->code, (uchar) (i))) + +/** + * Pushes an index onto the bytecode vector. For more information, see + * @a bc_vec_pushIndex() in src/vector.c and @a bc_program_index() in + * src/program.c. + * @param p The parser. + * @param idx The index to push onto the bytecode vector. + */ +#define bc_parse_pushIndex(p, idx) (bc_vec_pushIndex(&(p)->func->code, (idx))) + +/** + * A convenience macro for throwing errors in parse code. They take care of + * plumbing like passing in the current line the lexer is on. + * @param p The parser. + * @param e The error. + */ +#define bc_parse_err(p, e) (bc_vm_handleError((e), (p)->l.line)) + +/** + * A convenience macro for throwing errors in parse code. They take care of + * plumbing like passing in the current line the lexer is on. + * @param p The parser. + * @param e The error. + * @param ... The varags that are needed. + */ +#define bc_parse_verr(p, e, ...) \ + (bc_vm_handleError((e), (p)->l.line, __VA_ARGS__)) + +// Forward declarations. +struct BcParse; +struct BcProgram; + +/** + * A function pointer to call when more parsing is needed. + * @param p The parser. + */ +typedef void (*BcParseParse)(struct BcParse* p); + +/** + * A function pointer to call when an expression needs to be parsed. This can + * happen for read() expressions or dc strings. + * @param p The parser. + * @param flags The flags for what is allowed or required. (See flags above.) + */ +typedef void (*BcParseExpr)(struct BcParse* p, uint8_t flags); + +/// The parser struct. +typedef struct BcParse { + + /// The lexer. + BcLex l; + +#if BC_ENABLED + /// The stack of flags for bc. (See comments in include/bc.h.) This stack is + /// *required* to have one item at all times. Not maintaining that invariant + /// will cause problems. + BcVec flags; + + /// The stack of exits. These are indices into the bytecode vector where + /// blocks for loops and if statements end. Basically, these are the places + /// to jump to when skipping code. + BcVec exits; + + /// The stack of conditionals. Unlike exits, which are indices to jump + /// *forward* to, this is a vector of indices to jump *backward* to, usually + /// to the conditional of a loop, hence the name. + BcVec conds; + + /// A stack of operators. When parsing expressions, the bc parser uses the + /// Shunting-Yard algorithm, which requires a stack of operators. This can + /// hold the stack for multiple expressions at once because the expressions + /// stack as well. For more information, see the Expression Parsing section + /// of the Development manual (manuals/development.md). + BcVec ops; + + /// A buffer to temporarily store a string in. This is because the lexer + /// might generate a string as part of its work, and the parser needs that + /// string, but it also needs the lexer to continue lexing, which might + /// overwrite the string stored in the lexer. This buffer is for copying + /// that string from the lexer to keep it safe. + BcVec buf; +#endif // BC_ENABLED + + /// A reference to the program to grab the current function when necessary. + struct BcProgram *prog; + + /// A reference to the current function. The function is what holds the + /// bytecode vector that the parser is filling. + BcFunc *func; + + /// The index of the function. + size_t fidx; + +#if BC_ENABLED + /// True if the bc parser just entered a function and an auto statement + /// would be valid. + bool auto_part; +#endif // BC_ENABLED + +} BcParse; + +/** + * Initializes a parser. + * @param p The parser to initialize. + * @param prog A referenc to the program. + * @param func The index of the current function. + */ +void bc_parse_init(BcParse *p, struct BcProgram *prog, size_t func); + +/** + * Frees a parser. This is not guarded by #ifndef NDEBUG because a separate + * parser is created at runtime to parse read() expressions and dc strings. + * @param p The parser to free. + */ +void bc_parse_free(BcParse *p); + +/** + * Resets the parser. Resetting means erasing all state to the point that the + * parser would think it was just initialized. + * @param p The parser to reset. + */ +void bc_parse_reset(BcParse *p); + +/** + * Adds a string. See @a BcProgram in include/program.h for more details. + * @param p The parser that parsed the string. + */ +void bc_parse_addString(BcParse *p); + +/** + * Adds a number. See @a BcProgram in include/program.h for more details. + * @param p The parser that parsed the number. + */ +void bc_parse_number(BcParse *p); + +/** + * Update the current function in the parser. + * @param p The parser. + * @param fidx The index of the new function. + */ +void bc_parse_updateFunc(BcParse *p, size_t fidx); + +/** + * Adds a new variable or array. See @a BcProgram in include/program.h for more + * details. + * @param p The parser that parsed the variable or array name. + * @param name The name of the variable or array to add. + * @param var True if the name is for a variable, false if it's for an array. + */ +void bc_parse_pushName(const BcParse* p, char *name, bool var); + +/** + * Sets the text that the parser will parse. + * @param p The parser. + * @param text The text to lex. + * @param is_stdin True if the text is from stdin, false otherwise. + */ +void bc_parse_text(BcParse *p, const char *text, bool is_stdin); + +// References to const 0 and 1 strings for special cases. bc and dc have +// specific instructions for 0 and 1 because they pop up so often and (in the +// case of 1), increment/decrement operators. +extern const char bc_parse_zero[2]; +extern const char bc_parse_one[2]; + +#endif // BC_PARSE_H |