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#include "eval.h"
#include "list.h"
#include "atom.h"
#include "parse.h"
#include "env.h"
#include <stdio.h>
#include <string.h>
static int atom_cmp(struct list *a, struct list *b)
{
if (ATOM_TYPE(a) != ATOM_TYPE(b))
return 0;
if (IS_TRUE(a) && !IS_TRUE(b))
return 0;
if (IS_FALSE(a) && !IS_FALSE(b))
return 0;
if (IS_TRUE(b) && !IS_TRUE(a))
return 0;
if (IS_FALSE(b) && !IS_FALSE(a))
return 0;
if (IS_NIL(a) && !IS_NIL(b))
return 0;
if (IS_NIL(b) && !IS_NIL(a))
return 0;
int result = 1;
switch (ATOM_TYPE(a))
{
case ATOM_INT:
if (LIST_GET_ATOM(a)->l != LIST_GET_ATOM(b)->l)
result = 0;
break;
case ATOM_STR:
case ATOM_SYMBOL:
if (strcmp(LIST_GET_ATOM(a)->str.str, LIST_GET_ATOM(b)->str.str) != 0)
result = 0;
break;
case ATOM_LIST:
{
struct list *ai = LIST_GET_ATOM(a)->list;
struct list *bi = LIST_GET_ATOM(b)->list;
while (ai && bi)
{
if (!atom_cmp(ai, bi))
{
result = 0;
break;
}
ai = ai->next;
bi = bi->next;
}
if (ai != NULL || bi != NULL)
result = 0;
break;
}
}
return result;
}
struct list *eval(struct list *list)
{
struct list env;
memset(&env, 0, sizeof(env));
return eval_env(list, &env);
}
struct list *eval_str(const char *str)
{
struct list env;
memset(&env, 0, sizeof(env));
return eval_str_env(str, &env);
}
struct list *eval_env(struct list *expr, struct list *env)
{
if (IS_SYM(expr))
{
struct atom *atom = env_lookup(env, LIST_GET_ATOM(expr)->str.str);
if (atom)
{
return list_append(NULL, atom);
}
else
{
printf("error: undefined variable: %s\n",
LIST_GET_ATOM(expr)->str.str);
return list_append(NULL, &nil_atom);
}
}
if (!IS_LIST(expr))
return expr;
struct list *l = LIST_GET_ATOM(expr)->list;
if (IS_SYM(l))
{
const char *sym = LIST_GET_ATOM(l)->str.str;
if (strcmp(sym, "quote") == 0)
{
return l->next;
}
else if (strcmp(sym, "atom") == 0)
{
if (IS_LIST(l->next))
{
return list_append(NULL, &false_atom);
}
else
{
return list_append(NULL, &true_atom);
}
}
else if (strcmp(sym, "eq") == 0)
{
struct list *a = CDR(l);
struct list *b = CDR(a);
if (!a || !b)
{
printf("error: eq takes 2 arguments\n");
return list_append(NULL, &nil_atom);
}
a = eval_env(a, env);
b = eval_env(b, env);
if (atom_cmp(a, b))
return list_append(NULL, &true_atom);
return list_append(NULL, &false_atom);
}
else if (strncmp(sym, "+", 1) == 0 ||
strncmp(sym, "-", 1) == 0 ||
strncmp(sym, "/", 1) == 0 ||
strncmp(sym, "*", 1) == 0)
{
struct list *oper = CAR(l);
struct list *a = CDR(oper);
struct list *b = CDDR(oper);
if (!a || !b)
return list_append(NULL, &nil_atom);
a = eval_env(a, env);
b = eval_env(b, env);
if (!(ATOM_TYPE(a) == ATOM_TYPE(b) && ATOM_TYPE(a) == ATOM_INT))
return list_append(NULL, &nil_atom);
long numa = LIST_GET_ATOM(a)->l;
long numb = LIST_GET_ATOM(b)->l;
long numr;
switch (*sym)
{
case '+':
numr = numa + numb;
break;
case '-':
numr = numa - numb;
break;
case '/':
numr = numa / numb;
break;
case '*':
numr = numa * numb;
break;
}
struct list *result = list_append(NULL, atom_new_int(numr));
return result;
}
else if (strncmp(sym, ">", 1) == 0)
{
struct list *oper = CAR(l);
struct list *a = CDR(oper);
struct list *b = CDDR(oper);
if (!a || !b)
return list_append(NULL, &nil_atom);
a = eval_env(a, env);
b = eval_env(b, env);
if (!(ATOM_TYPE(a) == ATOM_TYPE(b) && ATOM_TYPE(a) == ATOM_INT))
return list_append(NULL, &nil_atom);
long numa = LIST_GET_ATOM(a)->l;
long numb = LIST_GET_ATOM(b)->l;
if (numa > numb)
return list_append(NULL, &true_atom);
else
return list_append(NULL, &false_atom);
}
else if (strcmp(sym, "if") == 0)
{
struct list *predicate = CDR(l);
struct list *true_case = CDR(predicate);
struct list *false_case = CDR(true_case);
if (!predicate || !true_case || !false_case)
return list_append(NULL, &nil_atom);
predicate = eval_env(predicate, env);
if (IS_TRUE(predicate))
return eval_env(true_case, env);
else
return eval_env(false_case, env);
}
else if (strcmp(sym, "mod") == 0)
{
struct list *a = CDR(l);
struct list *b = CDR(a);
if (!a || !b)
{
printf("error: mod takes two arguments\n");
return list_append(NULL, &nil_atom);
}
a = eval_env(a, env);
b = eval_env(b, env);
if (!IS_INT(a) || !IS_INT(b))
{
printf("error: mod arguments must be integers\n");
return list_append(NULL, &nil_atom);
}
long result = LIST_GET_ATOM(a)->l % LIST_GET_ATOM(b)->l;
return list_append(NULL, atom_new_int(result));
}
else if (strcmp(sym, "define") == 0)
{
struct list *expr_name = CDR(l);
struct list *expr_value = CDR(expr_name);
if (!expr_name || !expr_value)
{
printf("error: define takes two arguments\n");
return list_append(NULL, &nil_atom);
}
if (!IS_SYM(expr_name))
{
printf("error: define: first arg must be symbol\n");
return list_append(NULL, &nil_atom);
}
expr_value = eval_env(expr_value, env);
env_set(env, LIST_GET_ATOM(expr_name)->str.str,
LIST_GET_ATOM(expr_value));
return list_append(NULL, expr_value);
}
}
else if (IS_LIST(l))
{
return eval(l);
}
return list_append(NULL, &nil_atom);
}
struct list *eval_str_env(const char *expr, struct list *env)
{
struct list *result;
int pos = 0;
result = eval_env(parse(expr, &pos), env);
return result;
}
#ifdef BUILD_TEST
#include "test_util.h"
TEST(nested_expression)
{
struct list *result = eval_str("(eq #f (> (- (+ 1 3) (* 2 (mod 7 4))) 4))");
ASSERT_TRUE(result != NULL);
ASSERT_TRUE(IS_TRUE(result));
}
TEST(basic_if)
{
struct list *result = eval_str("(if #t 42 1000)");
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_INT, ATOM_TYPE(result));
ASSERT_EQ(42, LIST_GET_ATOM(result)->l);
}
TEST(if_with_sub_expressions)
{
struct list *result = eval_str("(if (> 1 2) (- 1000 1) (+ 40 (- 3 1)))");
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_INT, ATOM_TYPE(result));
ASSERT_EQ(42, LIST_GET_ATOM(result)->l);
}
/* EVALUTE WITH ENVIRONMENT TESTS */
TEST(evaluate_symbol)
{
struct list *env = env_new();
env_set(env, "foo", atom_new_int(42));
struct list *result = eval_str_env("foo", env);
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_INT, ATOM_TYPE(result));
ASSERT_EQ(42, LIST_GET_ATOM(result)->l);
}
TEST(evaluate_missing_symbol)
{
struct list *env = env_new();
struct list *result = eval_str_env("foo", env);
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_NIL, ATOM_TYPE(result));
}
TEST(define)
{
struct list *env = env_new();
struct list *result = eval_str_env("(define x 100)", env);
ASSERT_TRUE(result != NULL);
struct atom *atom = env_lookup(env, "x");
ASSERT_TRUE(atom != NULL);
ASSERT_EQ(ATOM_INT, atom->type);
ASSERT_EQ(100, atom->l);
}
TEST(define_missing_value)
{
struct list *env = env_new();
struct list *result = eval_str_env("(define x)", env);
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_NIL, ATOM_TYPE(result));
struct atom *atom = env_lookup(env, "x");
ASSERT_TRUE(atom == NULL);
}
TEST(define_nonsymbol_as_name)
{
struct list *env = env_new();
struct list *result = eval_str_env("(define 1 100)", env);
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_NIL, ATOM_TYPE(result));
}
TEST(define_with_val_as_expr)
{
struct list *env = env_new();
struct list *result = eval_str_env("(define x (* 3 3))", env);
ASSERT_TRUE(result != NULL);
struct atom *atom = env_lookup(env, "x");
ASSERT_TRUE(atom != NULL);
ASSERT_EQ(ATOM_INT, atom->type);
ASSERT_EQ(9, atom->l);
}
#endif /* BUILD_TEST */
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