3 files changed, 104 insertions, 0 deletions
diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..431d8a5
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,11 @@
+#include <stdio.h>
+#include <parse.h>
+#include <term.h>
+
+int main(void)
+{
+	struct term *term = parse("([[((0 1) [(1 0)])]] [0])");
+	print_term(term);
+	free_term(term);
+	return 0;
+}
diff --git a/src/parse.c b/src/parse.c
new file mode 100644
index 0000000..00fd498
--- /dev/null
+++ b/src/parse.c
@@ -0,0 +1,36 @@
+// Just for debugging purposes
+// -> parses custom bruijn syntax
+
+#include <parse.h>
+#include <term.h>
+#include <stdio.h>
+
+static struct term *rec(const char **term)
+{
+	struct term *res = 0;
+	if (!**term) {
+		fprintf(stderr, "invalid parsing state!\n");
+	} else if (**term == '[') {
+		(*term)++;
+		res = new_term(ABS);
+		res->u.abs.term = rec(term);
+	} else if (**term == '(') {
+		(*term)++;
+		res = new_term(APP);
+		res->u.app.lhs = rec(term);
+		res->u.app.rhs = rec(term);
+	} else if (**term >= '0' && **term <= '9') {
+		res = new_term(VAR);
+		res->u.var = **term - '0';
+		(*term)++;
+	} else {
+		(*term)++;
+		res = rec(term); // this is quite tolerant..
+	}
+	return res;
+}
+
+struct term *parse(const char *term)
+{
+	return rec(&term);
+}
diff --git a/src/term.c b/src/term.c
new file mode 100644
index 0000000..f288653
--- /dev/null
+++ b/src/term.c
@@ -0,0 +1,57 @@
+#include <term.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+struct term *new_term(term_type type)
+{
+	struct term *term = calloc(1, sizeof(*term));
+	if (!term) {
+		fprintf(stderr, "Out of memory!\n");
+		abort();
+	}
+	term->type = type;
+	return term;
+}
+
+void free_term(struct term *term)
+{
+	switch (term->type) {
+	case ABS:
+		free_term(term->u.abs.term);
+		free(term);
+		break;
+	case APP:
+		free_term(term->u.app.lhs);
+		free_term(term->u.app.rhs);
+		free(term);
+		break;
+	case VAR:
+		free(term);
+		break;
+	default:
+		fprintf(stderr, "Invalid type %d\n", term->type);
+	}
+}
+
+void print_term(struct term *term)
+{
+	switch (term->type) {
+	case ABS:
+		printf("[");
+		print_term(term->u.abs.term);
+		printf("]");
+		break;
+	case APP:
+		printf("(");
+		print_term(term->u.app.lhs);
+		printf(" ");
+		print_term(term->u.app.rhs);
+		printf(")");
+		break;
+	case VAR:
+		printf("%d", term->u.var);
+		break;
+	default:
+		fprintf(stderr, "Invalid type %d\n", term->type);
+	}
+}