Momentum-Apps/calculator/tinyexpr.h

// SPDX-License-Identifier: Zlib
/*
 * TINYEXPR - Tiny recursive descent parser and evaluation engine in C
 *
 * Copyright (c) 2015-2020 Lewis Van Winkle
 *
 * http://CodePlea.com
 *
 * This software is provided 'as-is', without any express or implied
 * warranty. In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 * claim that you wrote the original software. If you use this software
 * in a product, an acknowledgement in the product documentation would be
 * appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 * misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */

#ifndef TINYEXPR_H
#define TINYEXPR_H

#ifdef __cplusplus
extern "C" {
#endif

typedef struct te_expr {
    int type;
    union {
        double value;
        const double* bound;
        const void* function;
    };
    void* parameters[1];
} te_expr;

enum {
    TE_VARIABLE = 0,

    TE_FUNCTION0 = 8,
    TE_FUNCTION1,
    TE_FUNCTION2,
    TE_FUNCTION3,
    TE_FUNCTION4,
    TE_FUNCTION5,
    TE_FUNCTION6,
    TE_FUNCTION7,

    TE_CLOSURE0 = 16,
    TE_CLOSURE1,
    TE_CLOSURE2,
    TE_CLOSURE3,
    TE_CLOSURE4,
    TE_CLOSURE5,
    TE_CLOSURE6,
    TE_CLOSURE7,

    TE_FLAG_PURE = 32
};

typedef struct te_variable {
    const char* name;
    const void* address;
    int type;
    void* context;
} te_variable;

/* Parses the input expression, evaluates it, and frees it. */
/* Returns NaN on error. */
double te_interp(const char* expression, int* error);

/* Parses the input expression and binds variables. */
/* Returns NULL on error. */
te_expr*
    te_compile(const char* expression, const te_variable* variables, int var_count, int* error);

/* Evaluates the expression. */
double te_eval(const te_expr* n);

/* Prints debugging information on the syntax tree. */
void te_print(const te_expr* n);

/* Frees the expression. */
/* This is safe to call on NULL pointers. */
void te_free(te_expr* n);

#ifdef __cplusplus
}
#endif

#endif /*TINYEXPR_H*/