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#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <math.h>
#include <string.h>
#include "sheets.h"
/*
EXPR := VALUE
| VALUE POSTFIX
| '(' EXPR ')'
VALUE := NUM
| LOC
POSTFIX := OP EXPR
OP := '+' | '-' | '*' | '/' | '^'
lOC := '[' NUM ',' NUM ']'
*/
#define TODO(s) fprintf(stderr, "TODO:%d: %s\n", __LINE__, s); exit(1);
typedef struct expr expr;
typedef struct value value; /* for recursive case */
typedef struct postfix postfix;
typedef enum exprType {
VALUE,
POSTFIX,
NESTED,
} exprType;
typedef enum valueType {
NUM,
LOC,
} valueType;
typedef struct loc {
int x, y;
} loc;
typedef struct expr {
char *expr;
exprType t;
union {
expr *nested;
struct {
value *value;
postfix *postfix;
};
};
} expr;
typedef struct postfix {
char op;
expr *expr;
} postfix;
typedef struct value {
valueType t;
union {
int num;
loc *loc;
};
} value;
char isop(char c) {
switch (c) {
case '+':
case '-':
case '*':
case '/':
case '^':
return c;
}
return 0;
}
char *in;
char *Pin;
void consumeleading(char c) {
loop:
if (*in == c) {
in++;
goto loop;
}
}
expr *parseExpr();
loc *parseLoc() {
consumeleading(' ');
loc *l = malloc(sizeof(loc));
if (*in == '[') {
int i;
sscanf(in, "[%d,%d]%n", &l->x, &l->y, &i);
if (i != 0) {
in += i;
return l;
}
TODO("ERROR");
}
return NULL;
}
postfix *parsePostfix() {
consumeleading(' ');
postfix *p = malloc(sizeof(postfix));
if (p->op = isop(*in)) {
in++;
if (p->expr = parseExpr())
return p;
}
return NULL;
}
value *parseValue() {
consumeleading(' ');
value *v = malloc(sizeof(value));
if (v->loc = parseLoc()) {
v->t = LOC;
return v;
}
else if (isdigit(*in)) {
int i;
sscanf(in, "%d%n", &v->num, &i);
if (i != 0) {
in += i;
v->t = NUM;
return v;
}
TODO("ERROR");
}
return NULL;
}
expr *parseExpr() {
consumeleading(' ');
expr *e = malloc(sizeof(expr));
if (e->value = parseValue()) {
e->t = VALUE;
if (e->postfix = parsePostfix())
e->t = POSTFIX;
return e;
}
else if (*in == '(') {
in++;
if (e->nested = parseExpr())
if (*in == ')') {
e->t = NESTED;
return e;
}
TODO("ERROR");
}
return NULL;
}
double evalExpr(expr *e, sheet *s);
double evalValue(value *v, sheet *s) {
if (v->t == NUM) return v->num;
return evalExpr(s->cells[v->loc->y][v->loc->x], s);
}
double evalPostfix(value *v, postfix *p, sheet *s) {
switch (p->op) {
case '+': return evalValue(v, s) + evalExpr(p->expr, s);
case '-': return evalValue(v, s) - evalExpr(p->expr, s);
case '*': return evalValue(v, s) * evalExpr(p->expr, s);
case '/': return evalValue(v, s) / evalExpr(p->expr, s);
case '^': return pow(evalValue(v, s), evalExpr(p->expr, s));
}
}
double evalExpr(expr *e, sheet *s) {
switch (e->t) {
case VALUE: return evalValue(e->value, s); break;
case POSTFIX: return evalPostfix(e->value, e->postfix, s); break;
case NESTED: return evalExpr(e->nested, s);
}
}
expr *makeNumber(int n) {
in = Pin;
memset(in, 0, 255);
snprintf(in, 16, "%d", n);
expr *e = parseExpr();
e->expr = strdup(Pin);
return e;
}
void freeValue(value *v) {
if (v->t == LOC) free(v->loc);
free(v);
}
void freePostfix(value *v, postfix *p) {
freeValue(v);
freeExpr(p->expr);
free(p);
}
void freeExpr(expr *e) {
switch (e->t) {
case VALUE: freeValue(e->value); break;
case POSTFIX: freePostfix(e->value, e->postfix); break;
case NESTED: freeExpr(e->nested); break;
}
free(e);
}
|
