From 0478e6930517d63b30630c88a815d99f6e756c09 Mon Sep 17 00:00:00 2001
From: Peter Mikkelsen <peter@pmikkelsen.com>
Date: Tue, 20 Jul 2021 23:17:16 +0000
Subject: Throw errors when trying to evaluate goals that cannot be evaluated

---
 eval.c | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'eval.c')

diff --git a/eval.c b/eval.c
index 09bb009..e57f28f 100644
--- a/eval.c
+++ b/eval.c
@@ -28,6 +28,11 @@ evalquery(Term *query)
 		if(flagdebug)
 			print("Working goal: %S:%S\n", module->name, prettyprint(goal, 0, 0, 0, nil));
 
+		if(goal->tag == VariableTerm)
+			goal = instantiationerror();
+		if(goal->tag != AtomTerm && goal->tag != CompoundTerm)
+			goal = typeerror(L"callable", goal);
+
 		Binding *bindings = nil;
 		Clause *clause = nil;
 		
-- 
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