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/*
* expr.h - Expressions and values
*
* Written 2009 by Werner Almesberger
* Copyright 2009 by Werner Almesberger
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#ifndef EXPR_H
#define EXPR_H
#include <math.h>
#define UNDEF HUGE_VAL
struct frame;
struct expr;
struct value;
enum num_type {
nt_none,
nt_mm,
nt_mil,
};
struct num {
enum num_type type;
int exponent;
double n;
};
typedef struct num (*op_type)(const struct expr *self,
const struct frame *frame);
struct expr {
op_type op;
union {
struct num num;
const char *var;
char *str;
struct {
struct expr *a;
struct expr *b;
} op;
} u;
int lineno;
};
extern struct num undef;
#define is_undef(num) ((num).type == nt_none)
#define is_dimensionless(num) (!(num).exponent)
static inline int is_distance(struct num num)
{
return (num.type == nt_mm || num.type == nt_mil) && num.exponent == 1;
}
void fail_expr(const struct expr *expr);
const char *str_unit(struct num n);
static inline struct num make_num(double n)
{
struct num res;
res.type = nt_mm;
res.exponent = 0;
res.n = n;
return res;
}
static inline struct num make_mm(double mm)
{
struct num res;
res.type = nt_mm;
res.exponent = 1;
res.n = mm;
return res;
}
static inline struct num make_mil(double mil)
{
struct num res;
res.type = nt_mil;
res.exponent = 1;
res.n = mil;
return res;
}
int to_unit(struct num *n);
struct num op_num(const struct expr *self, const struct frame *frame);
struct num op_var(const struct expr *self, const struct frame *frame);
struct num op_string(const struct expr *self, const struct frame *frame);
struct num op_sin(const struct expr *self, const struct frame *frame);
struct num op_cos(const struct expr *self, const struct frame *frame);
struct num op_sqrt(const struct expr *self, const struct frame *frame);
struct num op_minus(const struct expr *self, const struct frame *frame);
struct num op_add(const struct expr *self, const struct frame *frame);
struct num op_sub(const struct expr *self, const struct frame *frame);
struct num op_mult(const struct expr *self, const struct frame *frame);
struct num op_div(const struct expr *self, const struct frame *frame);
struct expr *new_op(op_type op);
struct expr *binary_op(op_type op, struct expr *a, struct expr *b);
struct num eval_var(const struct frame *frame, const char *name);
/*
* eval_str returns NULL if the result isn't a string. Evaluation may then
* be attempted with eval_num, and the result can be converted accordingly.
*/
const char *eval_str(const struct expr *expr, const struct frame *frame);
struct num eval_num(const struct expr *expr, const struct frame *frame);
/* if frame == NULL, we only check the syntax without expanding */
char *expand(const char *name, const struct frame *frame);
struct expr *new_num(struct num num);
struct expr *parse_expr(const char *s);
void free_expr(struct expr *expr);
int parse_var(const char *s, const char **id, struct value **values,
int max_values);
int parse_values(const char *s, struct value **values);
void free_values(struct value *values, int keep_expr);
#endif /* !EXPR_H */
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