// buildMappingLiteralExpression builds the CodeDOM for a mapping literal expression.
func (db *domBuilder) buildMappingLiteralExpression(node compilergraph.GraphNode) codedom.Expression {
	mappingScope, _ := db.scopegraph.GetScope(node)
	mappingType := mappingScope.ResolvedTypeRef(db.scopegraph.TypeGraph())

	eit := node.StartQuery().
		Out(parser.NodeMappingLiteralExpressionEntryRef).
		BuildNodeIterator()

	var entries = make([]codedom.ObjectLiteralEntryNode, 0)

	for eit.Next() {
		entryNode := eit.Node()

		// The key expression must be a string when produced. We either reference it directly (if a string)
		// or call .String() (if a Stringable).
		keyNode := entryNode.GetNode(parser.NodeMappingLiteralExpressionEntryKey)
		keyScope, _ := db.scopegraph.GetScope(keyNode)
		keyType := keyScope.ResolvedTypeRef(db.scopegraph.TypeGraph())

		var keyExpr = db.buildExpression(keyNode)
		if !keyType.HasReferredType(db.scopegraph.TypeGraph().StringType()) {
			stringMethod, _ := keyType.ResolveMember("String", typegraph.MemberResolutionInstance)

			keyExpr = codedom.MemberCall(
				codedom.MemberReference(db.buildExpression(keyNode), stringMethod, node),
				stringMethod,
				[]codedom.Expression{},
				keyNode)
		}

		// Get the expression for the value.
		valueExpr := db.getExpression(entryNode, parser.NodeMappingLiteralExpressionEntryValue)

		// Build an object literal expression with the (native version of the) key string and the
		// created value.
		entryExpr := codedom.ObjectLiteralEntryNode{
			codedom.NominalUnwrapping(keyExpr, db.scopegraph.TypeGraph().StringTypeReference(), keyNode),
			valueExpr,
			entryNode,
		}
		entries = append(entries, entryExpr)
	}

	if len(entries) == 0 {
		// Empty mapping. Call the Empty() constructor directly.
		constructor, _ := mappingType.ResolveMember("Empty", typegraph.MemberResolutionStatic)
		return codedom.MemberCall(
			codedom.MemberReference(codedom.TypeLiteral(mappingType, node), constructor, node),
			constructor,
			[]codedom.Expression{},
			node)
	}

	constructor, _ := mappingType.ResolveMember("overObject", typegraph.MemberResolutionStatic)
	return codedom.MemberCall(
		codedom.MemberReference(codedom.TypeLiteral(mappingType, node), constructor, node),
		constructor,
		[]codedom.Expression{codedom.ObjectLiteral(entries, node)},
		node)
}
// buildMappingInitializerExpression builds the CodeDOM for initializing a mapping literal expression.
func (db *domBuilder) buildMappingInitializerExpression(mappingType typegraph.TypeReference, initializers map[string]codedom.Expression, node compilergraph.GraphNode) codedom.Expression {
	var entries = make([]codedom.ObjectLiteralEntryNode, 0)
	for name, expr := range initializers {
		entries = append(entries,
			codedom.ObjectLiteralEntryNode{
				codedom.LiteralValue(strconv.Quote(name), expr.BasisNode()),
				expr,
				expr.BasisNode(),
			})
	}

	if len(entries) == 0 {
		// Empty mapping. Call the Empty() constructor directly.
		constructor, _ := mappingType.ResolveMember("Empty", typegraph.MemberResolutionStatic)
		return codedom.MemberCall(
			codedom.MemberReference(codedom.TypeLiteral(mappingType, node), constructor, node),
			constructor,
			[]codedom.Expression{},
			node)
	}

	constructor, _ := mappingType.ResolveMember("overObject", typegraph.MemberResolutionStatic)
	return codedom.MemberCall(
		codedom.MemberReference(codedom.TypeLiteral(mappingType, node), constructor, node),
		constructor,
		[]codedom.Expression{codedom.ObjectLiteral(entries, node)},
		node)
}