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#include <stdio.h>
#include <string.h>
#include "ast.h"
static const int precedence[ATOM_MAX] = {
[ATOM_ALPHABETIC] = 1,
[ATOM_NUMERIC] = 1,
[ATOM_UPPERCASE] = 1,
[ATOM_LOWERCASE] = 1,
[ATOM_CONTROL] = 1,
[ATOM_PUNCTUATION] = 1,
[ATOM_EVERYTHING] = 1,
[ATOM_REPETITION] = 2,
[ATOM_SEQUENCE] = 3,
[ATOM_LITERAL] = 3,
[ATOM_ALTERNATION] = 4,
};
static void print_repeat(const struct repeat *r)
{
if (r->max < 0) {
switch (r->min) {
case 0: printf("*"); break;
case 1: printf("+"); break;
default: printf("{%ld,}", r->min); break;
}
} else if (r->min == 0 && r->max == 1) {
printf("?");
} else if (r->min == r->max) {
printf("{%ld}", r->min);
} else {
printf("{%ld,%ld}", r->min, r->max);
}
}
static void print_literal(const char *s)
{
for (; *s; s++) {
switch (*s) {
case '.':
case '[':
case '{':
case '}':
case '(':
case ')':
case '\\':
case '*':
case '+':
case '?':
case '|':
case '^':
case '$':
putchar('\\');
default:
putchar(*s);
}
}
}
static int get_precedence(const struct atom *a)
{
if (a->type == ATOM_LITERAL) {
switch (strlen(a->u.literal)) {
case 0: return -1;
case 1: return precedence[ATOM_EVERYTHING];
default: return precedence[ATOM_SEQUENCE];
}
}
return precedence[a->type];
}
static void print_atom(const struct atom *a);
static void print_child_atom(const struct atom *child, const struct atom *parent)
{
int group = get_precedence(child) > get_precedence(parent);
if (group) printf("(");
print_atom(child);
if (group) printf(")");
}
static void print_atom(const struct atom *a)
{
switch (a->type) {
case ATOM_ALTERNATION:
print_child_atom(a->u.children[0], a);
printf("|");
print_child_atom(a->u.children[1], a);
break;
case ATOM_SEQUENCE:
print_child_atom(a->u.children[0], a);
print_child_atom(a->u.children[1], a);
break;
case ATOM_REPETITION:
print_child_atom(a->u.repeat.child, a);
print_repeat(&a->u.repeat.counts);
break;
case ATOM_LITERAL:
print_literal(a->u.literal);
break;
case ATOM_ALPHABETIC: printf("[:alpha:]"); break;
case ATOM_NUMERIC: printf("[:digit:]"); break;
case ATOM_UPPERCASE: printf("[:upper:]"); break;
case ATOM_LOWERCASE: printf("[:lower:]"); break;
case ATOM_CONTROL: printf("[:cntrl:]"); break;
case ATOM_PUNCTUATION: printf("[:punct:]"); break;
case ATOM_EVERYTHING: printf("."); break;
}
}
void print_regex(const struct atom *a)
{
printf("^");
print_atom(a);
printf("$\n");
}
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