From: Mark Thom <markjordanthom@gmail.com>
Date: Sat, 16 Sep 2017 21:25:11 +0000 (-0600)
Subject: fix indexing bug on anonvars.
X-Git-Tag: v0.8.110~689
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=e4e9b09175ffb4d7f0c2fcae0509658d704e73ef;p=scryer-prolog.git

fix indexing bug on anonvars.
---

diff --git a/src/prolog/codegen.rs b/src/prolog/codegen.rs
index 50377140..d67c32e0 100644
--- a/src/prolog/codegen.rs
+++ b/src/prolog/codegen.rs
@@ -462,13 +462,16 @@ impl<'a, TermMarker: Allocator<'a>> CodeGenerator<'a, TermMarker>
         let mut left_index = 0;
 
         for (right_index, clause) in clauses.iter().enumerate() {
-            if let Some(&Term::Var(_, _)) = clause.first_arg() {
-                if left_index < right_index {
-                    subseqs.push((left_index, right_index));
-                }
+            match clause.first_arg() {
+                Some(&Term::Var(_, _)) | Some(&Term::AnonVar) => {
+                    if left_index < right_index {
+                        subseqs.push((left_index, right_index));
+                    }
 
-                subseqs.push((right_index, right_index + 1));
-                left_index = right_index + 1;
+                    subseqs.push((right_index, right_index + 1));
+                    left_index = right_index + 1;
+                },
+                _ => {}
             }
         }
 
diff --git a/src/prolog/io.rs b/src/prolog/io.rs
index cb005a04..6610c233 100644
--- a/src/prolog/io.rs
+++ b/src/prolog/io.rs
@@ -254,8 +254,8 @@ pub fn eval<'a, 'b: 'a>(wam: &'a mut Machine, tl: &'b TopLevel) -> EvalSession<'
             wam.submit_decl(decl),
         &TopLevel::Predicate(ref clauses) => {
             let mut cg = CodeGenerator::<DebrayAllocator>::new();
-            let compiled_pred = cg.compile_predicate(clauses);
-            
+
+            let compiled_pred = cg.compile_predicate(clauses);            
             wam.add_predicate(clauses, compiled_pred)
         },
         &TopLevel::Fact(ref fact) => {