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#include "all.h"
#include <stdlib.h>
static inline char peek(const char **p) { return **p; }
static inline char advance(const char **p) { return *(*p)++; }
static ast_node_t *new_node(ast_type_e type, int val) {
ast_node_t *n = malloc(sizeof(ast_node_t));
n->type = type;
n->val = val;
n->next = NULL;
n->children = (node_vec){0};
return n;
}
static ast_node_t *parse_block(const char **p);
static ast_node_t *parse_single(const char **p) {
char c = peek(p);
switch (c) {
case '+': {
int count = 0;
while (peek(p) == '+') {
advance(p);
count++;
}
return new_node(AST_INC, count);
}
case '-': {
int count = 0;
while (peek(p) == '-') {
advance(p);
count++;
}
return new_node(AST_DEC, count);
}
case '>': {
int count = 0;
while (peek(p) == '>') {
advance(p);
count++;
}
return new_node(AST_PTR_INC, count);
}
case '<': {
int count = 0;
while (peek(p) == '<') {
advance(p);
count++;
}
return new_node(AST_PTR_DEC, count);
}
case '.':
advance(p);
return new_node(AST_OUT, 1);
case ',':
advance(p);
return new_node(AST_IN, 1);
case '[':
advance(p);
return parse_block(p);
case ']':
case '\0':
return NULL;
default:
advance(p); // ignore garbage
return NULL;
}
}
static ast_node_t *parse_block(const char **p) {
ast_node_t *loop = new_node(AST_LOOP, 1);
while (**p) {
if (**p == ']') {
advance(p);
break;
}
ast_node_t *child = parse_single(p);
if (child)
node_vec_push(&loop->children, child);
}
return loop;
}
ast_node_t *parse(const char *src) {
const char *p = src;
ast_node_t *head = NULL;
ast_node_t *tail = NULL;
while (*p) {
ast_node_t *node = parse_single(&p);
if (!node)
continue;
if (!head) {
head = tail = node;
} else {
tail->next = node;
tail = node;
}
}
return head;
}
void ast_free(ast_node_t *node) {
if (!node)
return;
if (node->next)
ast_free(node->next);
for (size_t i = 0; i < node->children.len; i++) {
ast_free(node->children._data[i]);
}
node_vec_free(&node->children);
free(node);
}
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