1 files changed, 65 insertions, 0 deletions
diff --git a/src/term.c b/src/term.c
new file mode 100644
index 0000000..e68611e
--- /dev/null
+++ b/src/term.c
@@ -0,0 +1,65 @@
+// Copyright (c) 2024, Marvin Borner <dev@marvinborner.de>
+// SPDX-License-Identifier: MIT
+
+#include <stdlib.h>
+#include <stdio.h>
+
+#include <term.h>
+#include <log.h>
+#include <print.h>
+
+Term *term_new(TermType type)
+{
+	struct term *term = malloc(sizeof(*term));
+	if (!term)
+		fatal("out of memory!\n");
+	term->type = type;
+	return term;
+}
+
+void term_free(Term *term)
+{
+	switch (term->type) {
+	case ABS:
+		term_free(term->u.abs.body);
+		free(term);
+		break;
+	case APP:
+		term_free(term->u.app.lhs);
+		term_free(term->u.app.rhs);
+		free(term);
+		break;
+	case IDX:
+		free(term);
+		break;
+	default:
+		fatal("invalid type %d\n", term->type);
+	}
+}
+
+void term_diff(Term *a, Term *b)
+{
+	if (a->type != b->type) {
+		fprintf(stderr, "Term a: ");
+		print_bruijn(a);
+		fprintf(stderr, "\nTerm b: ");
+		print_bruijn(b);
+		fatal("\ntype mismatch %d %d\n", a->type, b->type);
+	}
+
+	switch (a->type) {
+	case ABS:
+		term_diff(a->u.abs.body, b->u.abs.body);
+		break;
+	case APP:
+		term_diff(a->u.app.lhs, b->u.app.lhs);
+		term_diff(a->u.app.rhs, b->u.app.rhs);
+		break;
+	case IDX:
+		if (a->u.index != b->u.index)
+			fatal("var mismatch %d=%d\n", a->u.index, b->u.index);
+		break;
+	default:
+		fatal("invalid type %d\n", a->type);
+	}
+}