Extract substituteFunctionType()

1 files changed, 18 insertions, 11 deletions

diff --git a/src/main/java/org/shedlang/compiler/types/TypeSubstitution.java b/src/main/java/org/shedlang/compiler/types/TypeSubstitution.java
index 302fab7a..385706ca 100644
--- a/src/main/java/org/shedlang/compiler/types/TypeSubstitution.java
+++ b/src/main/java/org/shedlang/compiler/types/TypeSubstitution.java
@@ -21,17 +21,7 @@ public class TypeSubstitution {
             case ConstructedSumType constructedType ->
                 substituteConstructedSumType(constructedType, map);
 
-            case FunctionType functionType -> new FunctionType(
-                Optional.empty(),
-                functionType.positionalParams().stream()
-                    .map(param -> substituteType(param, map))
-                    .toList(),
-                functionType.namedParams().stream()
-                    .map(param -> new NamedParam(param.name(), substituteType(param.type(), map)))
-                    .toList(),
-                functionType.effect(),
-                substituteType(functionType.returnType(), map)
-            );
+            case FunctionType functionType -> substituteFunctionType(functionType, map);
 
             case IntType intType ->
                 type;
@@ -109,6 +99,23 @@ public class TypeSubstitution {
         );
     }
 
+    private static FunctionType substituteFunctionType(
+        FunctionType functionType,
+        TypeSubstitutionMap map
+    ) {
+        return new FunctionType(
+            Optional.empty(),
+            functionType.positionalParams().stream()
+                .map(param -> substituteType(param, map))
+                .toList(),
+            functionType.namedParams().stream()
+                .map(param -> new NamedParam(param.name(), substituteType(param.type(), map)))
+                .toList(),
+            functionType.effect(),
+            substituteType(functionType.returnType(), map)
+        );
+    }
+
     private static SimpleStructType substituteSimpleStructType(
         SimpleStructType type,
         TypeSubstitutionMap map