From: Mark Thom <mark.thom@unb.ca>
Date: Mon, 18 Nov 2019 00:18:11 +0000 (-0400)
Subject: correct failure to observe last call position in queries'
X-Git-Tag: v0.8.118~38^2~20
X-Git-Url: https://git.sagredo.dev/?a=commitdiff_plain;h=de88fdc4dcc12ac6d89a51d06f8d806731f98e9a;p=scryer-prolog.git

correct failure to observe last call position in queries'
---

diff --git a/src/prolog/machine/code_repo.rs b/src/prolog/machine/code_repo.rs
index df80644f..fee126e9 100644
--- a/src/prolog/machine/code_repo.rs
+++ b/src/prolog/machine/code_repo.rs
@@ -134,7 +134,7 @@ impl CodeRepo {
                 );
                 Some(RefOrOwned::Owned(call_clause))
             }
-            &CodePtr::CallN(arity, _) => {
+            &CodePtr::CallN(arity, _, last_call) => {
                 let call_clause = call_clause!(ClauseType::CallN, arity, 0, last_call);
                 Some(RefOrOwned::Owned(call_clause))
             }
diff --git a/src/prolog/machine/machine_indices.rs b/src/prolog/machine/machine_indices.rs
index ef3b7d2c..384bd3fc 100644
--- a/src/prolog/machine/machine_indices.rs
+++ b/src/prolog/machine/machine_indices.rs
@@ -309,7 +309,7 @@ pub enum REPLCodePtr {
 #[derive(Clone, PartialEq)]
 pub enum CodePtr {
     BuiltInClause(BuiltInClauseType, LocalCodePtr), // local is the successor call.
-    CallN(usize, LocalCodePtr),                     // arity, local.
+    CallN(usize, LocalCodePtr, bool),               // arity, local, last call.
     Local(LocalCodePtr),
     DynamicTransaction(DynamicTransactionType, LocalCodePtr), // the type of transaction, the return pointer.
     REPL(REPLCodePtr, LocalCodePtr),                          // the REPL code, the return pointer.
@@ -320,7 +320,7 @@ impl CodePtr {
     pub fn local(&self) -> LocalCodePtr {
         match self {
             &CodePtr::BuiltInClause(_, ref local)
-          | &CodePtr::CallN(_, ref local)
+          | &CodePtr::CallN(_, ref local, _)
           | &CodePtr::Local(ref local) => local.clone(),
             &CodePtr::VerifyAttrInterrupt(p) => LocalCodePtr::DirEntry(p),
             &CodePtr::REPL(_, p) | &CodePtr::DynamicTransaction(_, p) => p,
@@ -418,7 +418,7 @@ impl Add<usize> for CodePtr {
           | p @ CodePtr::VerifyAttrInterrupt(_)
           | p @ CodePtr::DynamicTransaction(..) => p,
             CodePtr::Local(local) => CodePtr::Local(local + rhs),
-            CodePtr::CallN(_, local) | CodePtr::BuiltInClause(_, local) => {
+            CodePtr::CallN(_, local, _) | CodePtr::BuiltInClause(_, local) => {
                 CodePtr::Local(local + rhs)
             }
         }
diff --git a/src/prolog/machine/machine_state.rs b/src/prolog/machine/machine_state.rs
index 8bcd2018..edb5f419 100644
--- a/src/prolog/machine/machine_state.rs
+++ b/src/prolog/machine/machine_state.rs
@@ -854,7 +854,7 @@ pub(crate) trait CallPolicy: Any {
                         return Ok(());
                     }
 
-                    machine_st.p = CodePtr::CallN(arity, machine_st.p.local());
+                    machine_st.p = CodePtr::CallN(arity, machine_st.p.local(), machine_st.last_call);
                 }
                 ClauseType::BuiltIn(built_in) => {
                     machine_st.setup_built_in_call(built_in.clone());