Expand - For loop desugar

4 files changed, 60 insertions, 13 deletions

diff --git a/src/ast/expr.hpp b/src/ast/expr.hpp
index 00694962..ca634e91 100644
--- a/src/ast/expr.hpp
+++ b/src/ast/expr.hpp
@@ -245,6 +245,15 @@ struct ExprNode_Match_Arm:
     
     unique_ptr<ExprNode>    m_code;
 
+
+    ExprNode_Match_Arm()
+    {}
+    ExprNode_Match_Arm(::std::vector<Pattern> patterns, unique_ptr<ExprNode> cond, unique_ptr<ExprNode> code):
+        m_patterns( mv$(patterns) ),
+        m_cond( mv$(cond) ),
+        m_code( mv$(code) )
+    {}
+
     SERIALISABLE_PROTOTYPES();
 };
     
diff --git a/src/expand/mod.cpp b/src/expand/mod.cpp
index 2f4fe0be..3d4f431e 100644
--- a/src/expand/mod.cpp
+++ b/src/expand/mod.cpp
@@ -343,6 +343,52 @@ struct CExpandExpr:
     void visit(::AST::ExprNode_Loop& node) override {
         this->visit_nodelete(node, node.m_cond);
         this->visit_nodelete(node, node.m_code);
+        Expand_Pattern(is_early, crate, modstack, this->cur_mod(),  node.m_pattern);
+        if(node.m_type == ::AST::ExprNode_Loop::FOR)
+        {
+            // TODO: Desugar into:
+            // {
+            //     let mut it = <_ as IntoIterator>::into_iter(`m_cond`);
+            //     `m_label`: loop {
+            //         match it.next() {
+            //         Some(`m_pattern`) => `m_code`,
+            //         None => break `m_label`,
+            //         }
+            //     }
+            // }
+            ::std::vector< ::AST::ExprNode_Match_Arm>   arms;
+            arms.push_back( ::AST::ExprNode_Match_Arm(
+                ::make_vec1( ::AST::Pattern(::AST::Pattern::TagEnumVariant(), ::AST::Path(::AST::Path::TagRelative(), {::AST::PathNode("Some")}), ::make_vec1( mv$(node.m_pattern) ) ) ),
+                nullptr,
+                mv$(node.m_code)
+                ) );
+            arms.push_back( ::AST::ExprNode_Match_Arm(
+                ::make_vec1( ::AST::Pattern(::AST::Pattern::TagValue(), ::AST::Pattern::Value::make_Named(::AST::Path(::AST::Path::TagRelative(), {::AST::PathNode("None")})) ) ),
+                nullptr,
+                ::AST::ExprNodeP(new ::AST::ExprNode_Flow(::AST::ExprNode_Flow::BREAK, node.m_label, nullptr))
+                ) );
+            ::std::vector< ::AST::ExprNodeP>    block_nodes;
+            block_nodes.push_back( ::AST::ExprNodeP(new ::AST::ExprNode_LetBinding(
+                ::AST::Pattern(::AST::Pattern::TagBind(), "it"),
+                TypeRef(),
+                ::AST::ExprNodeP(new ::AST::ExprNode_CallPath(
+                    ::AST::Path(::AST::Path::TagUfcs(), ::TypeRef(), ::AST::Path(::AST::Path::TagRelative(), {::AST::PathNode("IntoIterator")}), { ::AST::PathNode("into_iter") } ),
+                    ::make_vec1( mv$(node.m_cond) )
+                    ))
+                )) );
+            block_nodes.push_back( ::AST::ExprNodeP(new ::AST::ExprNode_Loop(
+                node.m_label,
+                ::AST::ExprNodeP(new ::AST::ExprNode_Match(
+                    ::AST::ExprNodeP(new ::AST::ExprNode_CallMethod(
+                        ::AST::ExprNodeP(new ::AST::ExprNode_NamedValue( ::AST::Path("it") )),
+                        ::AST::PathNode("next"),
+                        {}
+                        )),
+                    mv$(arms)
+                    ))
+                )) );
+            replacement.reset(new ::AST::ExprNode_Block( mv$(block_nodes), nullptr ));
+        }
     }
     void visit(::AST::ExprNode_Match& node) override {
         this->visit_nodelete(node, node.m_val);
diff --git a/src/hir/from_ast_expr.cpp b/src/hir/from_ast_expr.cpp
index b0f6f420..e5088d71 100644
--- a/src/hir/from_ast_expr.cpp
+++ b/src/hir/from_ast_expr.cpp
@@ -237,19 +237,10 @@ struct LowerHIR_ExprNode_Visitor:
                     ))
                 ) );
             break; }
-        case ::AST::ExprNode_Loop::FOR: {
-            // TODO: Desugar into:
-            // {
-            //     let mut it = <_ as IntoIterator>::into_iter(`m_cond`);
-            //     `m_label`: loop {
-            //         match it.next() {
-            //         Some(`m_pattern`) => `m_code`,
-            //         None => break `m_label`,
-            //         }
-            //     }
-            // }
+        case ::AST::ExprNode_Loop::FOR:
+            // NOTE: This should already be desugared (as a pass before resolve)
             TODO(v.get_pos(), "Desugar for loop");
-            break; }
+            break;
         }
     }
     virtual void visit(::AST::ExprNode_Match& v) override {
diff --git a/src/resolve/absolute.cpp b/src/resolve/absolute.cpp
index 2985419a..da27261f 100644
--- a/src/resolve/absolute.cpp
+++ b/src/resolve/absolute.cpp
@@ -595,6 +595,7 @@ void Resolve_Absolute_Expr(Context& context,  ::AST::ExprNode& node)
                 
                 if(arm.m_cond)
                     arm.m_cond->visit( *this );
+                assert( arm.m_code );
                 arm.m_code->visit( *this );
                 
                 this->context.pop_block();
@@ -710,7 +711,7 @@ void Resolve_Absolute_PatternValue(/*const*/ Context& context, ::AST::Pattern::V
     (Integer, ),
     (String, ),
     (Named,
-        assert( ! e.is_trivial() );
+        //assert( ! e.is_trivial() );
         Resolve_Absolute_Path(context, Span(), Context::LookupMode::Constant, e);
         )
     )