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Implement plus desugaring

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Camden Dixie O'Brien 2024-10-26 16:28:52 +01:00
parent 295b68efa2
commit 7e7a7f1cb7
2 changed files with 99 additions and 0 deletions
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62
lib/desugar.c
View File

@ -5,8 +5,70 @@
#include "desugar.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
static void deep_copy_term(parse_term_t *dst, parse_term_t *src);
static void deep_copy_sequence(parse_sequence_t *dst, parse_sequence_t *src)
{
dst->count = dst->capacity = src->count;
dst->contents = malloc(dst->capacity * sizeof(parse_term_t));
for (int i = 0; i < dst->count; ++i)
deep_copy_term(&dst->contents[i], &src->contents[i]);
}
static void deep_copy_term(parse_term_t *dst, parse_term_t *src)
{
assert(PARSE_TERM_WILDCARD != src->type);
assert(PARSE_TERM_CLASS != src->type);
memcpy(dst, src, sizeof(parse_term_t));
if (PARSE_TERM_SUBEXPR == src->type) {
dst->subexpr.capacity = src->subexpr.count;
dst->subexpr.contents
= malloc(dst->subexpr.capacity * sizeof(parse_sequence_t));
for (int i = 0; i < dst->subexpr.count; ++i) {
deep_copy_sequence(
&dst->subexpr.contents[i], &src->subexpr.contents[i]);
}
}
}
static void desugar_plus(parse_term_t *term)
{
parse_sequence_t *alternatives = malloc(sizeof(parse_sequence_t));
alternatives[0].count = alternatives[0].capacity = 2;
alternatives[0].contents = malloc(2 * sizeof(parse_term_t));
memcpy(&alternatives[0].contents[0], term, sizeof(parse_term_t));
deep_copy_term(&alternatives[0].contents[1], term);
alternatives[0].contents[0].quantifier = PARSE_QUANTIFIER_NONE;
alternatives[0].contents[1].quantifier = PARSE_QUANTIFIER_STAR;
term->quantifier = PARSE_QUANTIFIER_NONE;
term->type = PARSE_TERM_SUBEXPR;
term->subexpr.count = term->subexpr.capacity = 1;
term->subexpr.contents = alternatives;
}
static void desugar_term(parse_term_t *term)
{
switch (term->quantifier) {
case PARSE_QUANTIFIER_PLUS:
desugar_plus(term);
break;
case PARSE_QUANTIFIER_NONE:
case PARSE_QUANTIFIER_STAR:
break;
}
}
void desugar_regex(parse_tree_t *regex)
{
for (int i = 0; i < regex->count; ++i) {
for (int j = 0; j < regex->contents[i].count; ++j)
desugar_term(&regex->contents[i].contents[j]);
}
}

37
tests/desugar_tests.c
View File

@ -140,6 +140,42 @@ static void subexpr_a_is_unchanged(void)
parse_free_tree_children(&t);
}
static void a_plus_becomes_subexpr_aa_star(void)
{
parse_term_t *terms = malloc(1 * sizeof(parse_term_t));
terms[0].quantifier = PARSE_QUANTIFIER_PLUS;
terms[0].type = PARSE_TERM_LITERAL;
terms[0].literal = 'a';
parse_sequence_t *alternatives = malloc(1 * sizeof(parse_sequence_t));
alternatives[0].count = alternatives[0].capacity = 1;
alternatives[0].contents = terms;
parse_tree_t t = { .count = 1, .capacity = 1, .contents = alternatives };
desugar_regex(&t);
ASSERT_EQ(1, t.count);
ASSERT_NOT_NULL(t.contents);
ASSERT_EQ(1, t.contents[0].count);
ASSERT_NOT_NULL(t.contents[0].contents);
ASSERT_EQ(PARSE_QUANTIFIER_NONE, t.contents[0].contents[0].quantifier);
ASSERT_EQ(PARSE_TERM_SUBEXPR, t.contents[0].contents[0].type);
const parse_tree_t *inner = &t.contents[0].contents[0].subexpr;
ASSERT_EQ(1, inner->count);
ASSERT_NOT_NULL(inner->contents);
ASSERT_EQ(2, inner->contents[0].count);
ASSERT_NOT_NULL(inner->contents[0].contents);
ASSERT_EQ(
PARSE_QUANTIFIER_NONE, inner->contents[0].contents[0].quantifier);
ASSERT_EQ(PARSE_TERM_LITERAL, inner->contents[0].contents[0].type);
ASSERT_EQ('a', inner->contents[0].contents[0].literal);
ASSERT_EQ(
PARSE_QUANTIFIER_STAR, inner->contents[0].contents[1].quantifier);
ASSERT_EQ(PARSE_TERM_LITERAL, inner->contents[0].contents[1].type);
ASSERT_EQ('a', inner->contents[0].contents[1].literal);
parse_free_tree_children(&t);
}
int main(void)
{
TESTING_BEGIN();
@ -148,5 +184,6 @@ int main(void)
a_star_is_unchanged();
a_or_b_or_c_is_unchanged();
subexpr_a_is_unchanged();
a_plus_becomes_subexpr_aa_star();
return TESTING_END();
}