1 files changed, 99 insertions, 0 deletions
diff --git a/ast.c b/ast.c
new file mode 100644
index 0000000..d261b9d
--- /dev/null
+++ b/ast.c
@@ -0,0 +1,99 @@
+#include <stdarg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "ast.h"
+
+struct atom *ast;
+
+struct atom *mkatom(const struct atom *src)
+{
+	struct atom *ret = malloc(sizeof *ret);
+	if (ret) *ret = *src;
+	return ret;
+}
+
+static void ivprintf(int level, const char *fmt, va_list ap)
+{
+	printf("%*s", 4 * level, "");
+	vprintf(fmt, ap);
+}
+
+static void iprintf(int level, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	ivprintf(level, fmt, ap);
+	va_end(ap);
+}
+
+static void dump_atom_indent(const struct atom *a, int level);
+
+static void dump_atom_children(const struct atom *a, int level, const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+	ivprintf(level, fmt, ap);
+	va_end(ap);
+
+	iprintf(level, "{\n");
+	dump_atom_indent(a->u.children[0], level + 1);
+	dump_atom_indent(a->u.children[1], level + 1);
+	iprintf(level, "}\n");
+}
+
+const char *fmt_repeat(char *buf, const struct repeat *r)
+{
+	if (r->min == r->max)
+		sprintf(buf, "%ld", r->min);
+	else if (r->max < 0)
+		sprintf(buf, "%ld+", r->min);
+	else
+		sprintf(buf, "%ld - %ld", r->min, r->max);
+	return buf;
+}
+
+#define FMT_REPEAT(r) fmt_repeat((char[64]){0}, (r))
+
+static void dump_atom_indent(const struct atom *a, int level)
+{
+	switch (a->type) {
+	case ATOM_ALTERNATION:
+		dump_atom_children(a, level, "alternation\n");
+		break;
+
+	case ATOM_SEQUENCE:
+		dump_atom_indent(a->u.children[0], level);
+		dump_atom_indent(a->u.children[1], level);
+		break;
+
+	case ATOM_REPETITION:
+		if (a->u.repeat.counts.min == 1 && a->u.repeat.counts.max == 1) {
+			dump_atom_indent(a->u.repeat.child, level);
+		} else {
+			iprintf(level, "repeat %s times\n", FMT_REPEAT(&a->u.repeat.counts));
+			iprintf(level, "{\n");
+			dump_atom_indent(a->u.repeat.child, level + 1);
+			iprintf(level, "}\n");
+		}
+		break;
+
+	case ATOM_LITERAL:
+		iprintf(level, "literal: %s\n", a->u.literal);
+		break;
+
+	case ATOM_ALPHABETIC:  iprintf(level, "[:alpha:]\n"); break;
+	case ATOM_NUMERIC:     iprintf(level, "[:digit:]\n"); break;
+	case ATOM_UPPERCASE:   iprintf(level, "[:upper:]\n"); break;
+	case ATOM_LOWERCASE:   iprintf(level, "[:lower:]\n"); break;
+	case ATOM_CONTROL:     iprintf(level, "[:cntrl:]\n"); break;
+	case ATOM_PUNCTUATION: iprintf(level, "[:punct:]\n"); break;
+	case ATOM_EVERYTHING:  iprintf(level, "any\n");       break;
+	}
+}
+
+void dump_atom(const struct atom *a)
+{
+	dump_atom_indent(a, 0);
+}
+