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#include "parse.h"
#include "tokens.h"
#include "atom.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
struct atom *parse_token(struct token *token)
{
switch (token->type)
{
case TOKEN_INT:
return atom_new_int(strtol(token->s, NULL, 10));
case TOKEN_STR:
return atom_new_str(token->s, token->len);
case TOKEN_SYMBOL:
if (strncmp(token->s, "#t", 2) == 0)
return &true_atom;
else if (strncmp(token->s, "#f", 2) == 0)
return &false_atom;
else
return atom_new_sym(token->s, token->len);
default:
return NULL;
}
return NULL;
}
void parse_quote(const char *src, int *pos, struct atom **result)
{
struct atom *value = parse(src, pos);
struct atom *q = atom_new_sym("quote", 5);
struct atom *form = atom_new_list_empty();
LIST_INSERT_HEAD(form->list, q, entries);
LIST_INSERT_AFTER(q, value, entries);
*result = form;
}
int parse_list(const char *src, int *pos, struct atom **result)
{
struct token token;
int rc;
struct list *list;
struct atom *last = NULL;
list = calloc(1, sizeof(*list));
LIST_INIT(list);
while ((rc = get_next_token(src, pos, &token)))
{
struct atom *atom;
if (rc < 0)
break;
switch (token.type)
{
case TOKEN_LPAREN:
if (parse_list(src, pos, &atom) < 0)
return -1;
break;
case TOKEN_RPAREN:
goto out;
break;
case TOKEN_QUOTE:
parse_quote(src, pos, &atom);
break;
default:
atom = parse_token(&token);
break;
}
if (!last)
LIST_INSERT_HEAD(list, atom, entries);
else
LIST_INSERT_AFTER(last, atom, entries);
last = atom;
}
out:
if (rc < 0)
return rc;
if (LIST_EMPTY(list))
{
free(list);
*result = &nil_atom;
return 1;
}
*result = atom_new_list(list);
return 1;
}
struct atom *parse(const char *src, int *pos)
{
struct token token;
struct atom *atom = NULL;
int rc;
rc = get_next_token(src, pos, &token);
if (rc < 0)
return NULL;
switch (token.type)
{
case TOKEN_LPAREN:
if (parse_list(src, pos, &atom) < 0)
atom = NULL;
break;
case TOKEN_RPAREN:
printf("syntax error: unexpected ')'\n");
break;
case TOKEN_QUOTE:
parse_quote(src, pos, &atom);
break;
default:
atom = parse_token(&token);
break;
}
return atom;
}
#ifdef BUILD_TEST
#include "test_util.h"
static const char *test_src_fact =
"(define fact\n"
" ;; Factorial function\n"
" (lambda (n)\n"
" (if (eq n 0)\n"
" 1 ; Factorial of 0 is 1\n"
" (* n (fact (- n 1))))))\n"
"(fact 5) ;; this should evaluate to 120\n";
#define ASSERT_SYM(ATOM, SYM) \
ASSERT_TRUE(IS_SYM(ATOM)); \
ASSERT_STREQ(SYM, (ATOM)->str.str)
TEST(test_parse)
{
int pos = 0;
struct atom *list;
list = parse(test_src_fact, &pos);
ASSERT_TRUE(list != NULL);
ASSERT_TRUE(IS_LIST(list));
struct atom *a = CAR(list->list);
ASSERT_TRUE(a != NULL);
ASSERT_SYM(a, "define");
a = CDR(a);
ASSERT_TRUE(a != NULL);
ASSERT_SYM(a, "fact");
a = CDR(a);
ASSERT_TRUE(a != NULL);
}
TEST(parse_quote)
{
int pos = 0;
struct atom *result = parse("'foobar", &pos);
ASSERT_TRUE(result != NULL);
ASSERT_EQ(ATOM_LIST, result->type);
struct atom *op = CAR(result->list);
ASSERT_TRUE(op != NULL);
ASSERT_EQ(ATOM_SYMBOL, op->type);
ASSERT_STREQ("quote", op->str.str);
struct atom *a = CDR(op);
ASSERT_TRUE(a != NULL);
ASSERT_EQ(ATOM_SYMBOL, a->type);
ASSERT_STREQ("foobar", a->str.str);
}
#endif
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