Basic parsing

1 files changed, 36 insertions, 0 deletions

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);
+}