From 5f8bdc564b7319c692a7923ed60661d4f7b9d1a6 Mon Sep 17 00:00:00 2001
From: Mark Thom <markjordanthom@gmail.com>
Date: Mon, 22 Feb 2021 02:00:25 -0700
Subject: [PATCH] extend existing local predicate skeletons in
 LoadState::compile

---
 src/machine/compile.rs | 39 ++++++++++++++++++++++++++++++++-------
 src/machine/loader.rs  | 22 ++++++++++++++++++++++
 2 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/src/machine/compile.rs b/src/machine/compile.rs
index 9364d176..ebdcb134 100644
--- a/src/machine/compile.rs
+++ b/src/machine/compile.rs
@@ -1099,14 +1099,39 @@ impl<'a> LoadState<'a> {
                 }
             }
 
-            let mut skeleton = PredicateSkeleton::new();
-            skeleton.clause_clause_locs = clause_clause_locs;
+            match self
+                .wam
+                .indices
+                .get_local_predicate_skeleton_mut(
+                    &self.compilation_target,
+                    predicates.compilation_target.clone(),
+                    key.clone(),
+                )
+            {
+                Some(skeleton) => {
+                    self.retraction_info
+                        .push_record(RetractionRecord::SkeletonLocalClauseTruncateBack(
+                            self.compilation_target.clone(),
+                            predicates.compilation_target.clone(),
+                            key.clone(),
+                            skeleton.clause_clause_locs.len(),
+                        ));
 
-            self.add_local_extensible_predicate(
-                predicates.compilation_target.clone(),
-                key.clone(),
-                skeleton,
-            );
+                    skeleton.clause_clause_locs.extend_from_slice(
+                        &clause_clause_locs[0 ..]
+                    );
+                }
+                None => {
+                    let mut skeleton = PredicateSkeleton::new();
+                    skeleton.clause_clause_locs = clause_clause_locs;
+
+                    self.add_local_extensible_predicate(
+                        predicates.compilation_target.clone(),
+                        key.clone(),
+                        skeleton,
+                    );
+                }
+            }
         }
 
         set_code_index(
diff --git a/src/machine/loader.rs b/src/machine/loader.rs
index afa193d3..a9d45bcc 100644
--- a/src/machine/loader.rs
+++ b/src/machine/loader.rs
@@ -76,6 +76,7 @@ pub(crate) enum RetractionRecord {
     SkeletonClausePopFront(CompilationTarget, PredicateKey),
     SkeletonLocalClauseClausePopBack(CompilationTarget, CompilationTarget, PredicateKey),
     SkeletonLocalClauseClausePopFront(CompilationTarget, CompilationTarget, PredicateKey),
+    SkeletonLocalClauseTruncateBack(CompilationTarget, CompilationTarget, PredicateKey, usize),
     SkeletonClauseTruncateBack(CompilationTarget, PredicateKey, usize),
     SkeletonClauseStartReplaced(CompilationTarget, PredicateKey, usize, usize),
     RemovedSkeletonClause(
@@ -519,6 +520,27 @@ impl<'a> Drop for LoadState<'a> {
                         None => {}
                     }
                 }
+                RetractionRecord::SkeletonLocalClauseTruncateBack(
+                    src_compilation_target,
+                    local_compilation_target,
+                    key,
+                    len,
+                ) => {
+                    match self
+                        .wam
+                        .indices
+                        .get_local_predicate_skeleton_mut(
+                            &src_compilation_target,
+                            local_compilation_target,
+                            key,
+                        )
+                    {
+                        Some(skeleton) => {
+                            skeleton.clause_clause_locs.truncate_back(len);
+                        }
+                        None => {}
+                    }
+                }
                 RetractionRecord::SkeletonClauseTruncateBack(compilation_target, key, len) => {
                     match self
                         .wam
-- 
2.54.0