Add a term parser.

1 files changed, 61 insertions, 0 deletions

diff --git a/prettyprint.c b/prettyprint.c
new file mode 100644
index 0000000..499fc84
--- /dev/null
+++ b/prettyprint.c
@@ -0,0 +1,61 @@
+#include <u.h>
+#include <libc.h>
+
+#include "dat.h"
+#include "fns.h"
+
+Rune *prettyprintlist(Term *, Rune *, int);
+
+Rune *
+prettyprint(Term *t)
+{
+	Rune *result;
+	Rune *args;
+
+	switch(t->tag){
+	case CompoundTerm:
+		args = prettyprintlist(t->children, L", ", 0);
+		result = runesmprint("%S(%S)", t->text, args);
+		free(args);
+		break;
+	case AtomTerm:
+	case VariableTerm:
+		result = runesmprint("%S", t->text);
+		break;
+	case NumberTerm:
+		if(t->numbertype == NumberInt)
+			result = runesmprint("%lld", t->ival);
+		else
+			result = runesmprint("%f", t->dval);
+		break;
+	default:
+		result = runesmprint("cant print term with tag %d", t->tag);
+		break;
+	}
+
+	return result;
+}
+
+Rune *
+prettyprintlist(Term *t, Rune *sep, int end)
+{
+	if(t == nil){
+		if(end)
+			return runesmprint("%S", sep);
+		else
+			return runesmprint("");
+	}
+
+	Rune *str = prettyprint(t);
+	Rune *rest = prettyprintlist(t->next, sep, end);
+	Rune *result;
+
+	if(t->next != nil)
+		result = runesmprint("%S%S%S", str, sep, rest);
+	else
+		result = runesmprint("%S%S", str, end ? rest : L"");
+
+	free(str);
+	free(rest);
+	return result;
+}
\ No newline at end of file