Extract Variable to be top-level interface

8 files changed, 47 insertions, 41 deletions

diff --git a/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java b/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java
index 53853305..c30c745a 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/EnvironmentBuilder.java
@@ -11,9 +11,9 @@ import java.util.List;
 public class EnvironmentBuilder {
     public static final EnvironmentBuilder EMPTY = new EnvironmentBuilder(Empty.map());
 
-    private PMap<String, TypeCheckerContext.Variable> environment;
+    private PMap<String, Variable> environment;
 
-    private EnvironmentBuilder(PMap<String, TypeCheckerContext.Variable> environment) {
+    private EnvironmentBuilder(PMap<String, Variable> environment) {
         this.environment = environment;
     }
 
@@ -31,17 +31,17 @@ public class EnvironmentBuilder {
         if (environment.containsKey(name)) {
             throw new DuplicateVariableName(name, source);
         }
-        return new EnvironmentBuilder(environment.plus(name, new TypeCheckerContext.Variable.Undefined()));
+        return new EnvironmentBuilder(environment.plus(name, new Variable.Undefined()));
     }
 
-    public EnvironmentBuilder add(String name, TypeCheckerContext.Variable variable, Source source) {
+    public EnvironmentBuilder add(String name, Variable variable, Source source) {
         if (environment.containsKey(name)) {
             throw new DuplicateVariableName(name, source);
         }
         return new EnvironmentBuilder(environment.plus(name, variable));
     }
 
-    public PMap<String, TypeCheckerContext.Variable> build() {
+    public PMap<String, Variable> build() {
         return environment;
     }
 
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
index ee35fa1f..5377f562 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeChecker.java
@@ -49,10 +49,10 @@ public class TypeChecker {
         }
 
         return switch (type.get()) {
-            case TypeCheckerContext.Variable.Defined defined ->
+            case Variable.Defined defined ->
                 defined.type();
 
-            case TypeCheckerContext.Variable.Undefined undefined ->
+            case Variable.Undefined undefined ->
                 throw new ReferenceBeforeDefinitionError(name, source);
         };
     }
@@ -64,10 +64,10 @@ public class TypeChecker {
             }
 
             return switch (type.get()) {
-                case TypeCheckerContext.Variable.Defined defined ->
+                case Variable.Defined defined ->
                     defined.type();
 
-                case TypeCheckerContext.Variable.Undefined undefined ->
+                case Variable.Undefined undefined ->
                     throw new ReferenceBeforeDefinitionError(name, source);
             };
         });
@@ -458,7 +458,7 @@ public class TypeChecker {
         for (var param : typedParams.all()) {
             bodyEnvironment = bodyEnvironment.add(
                 param.name(),
-                TypeCheckerContext.defined(param.type().value()),
+                Variable.defined(param.type().value()),
                 param.source()
             );
         }
diff --git a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java
index d6a10d35..30778094 100644
--- a/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java
+++ b/src/main/java/org/shedlang/compiler/typechecker/TypeCheckerContext.java
@@ -30,19 +30,6 @@ public class TypeCheckerContext {
         ))
     );
 
-    public sealed interface Variable {
-        record Undefined() implements Variable {}
-        record Defined(Type type) implements Variable {}
-    }
-
-    public static Variable defined(Type type) {
-        return new Variable.Defined(type);
-    }
-
-    public static Variable undefined() {
-        return new Variable.Undefined();
-    }
-
     private sealed interface StackElement {
         boolean isBoundInElement(String name);
         StackElement withFreeVariable(String name, Source referenceSource);
@@ -152,7 +139,7 @@ public class TypeCheckerContext {
 
     public TypeCheckerContext enterNamespaceWithDefinedVariables(PMap<String, Type> variables) {
         var environment = variables.entrySet().stream()
-            .map(x -> Map.entry(x.getKey(), TypeCheckerContext.defined(x.getValue())))
+            .map(x -> Map.entry(x.getKey(), Variable.defined(x.getValue())))
             .collect(PCollectors.toMap());
 
         return enterNamespace(environment);
diff --git a/src/main/java/org/shedlang/compiler/typechecker/Variable.java b/src/main/java/org/shedlang/compiler/typechecker/Variable.java
new file mode 100644
index 00000000..7fd7ca23
--- /dev/null
+++ b/src/main/java/org/shedlang/compiler/typechecker/Variable.java
@@ -0,0 +1,19 @@
+package org.shedlang.compiler.typechecker;
+
+import org.shedlang.compiler.types.Type;
+
+public sealed interface Variable {
+    static Variable defined(Type type) {
+        return new Variable.Defined(type);
+    }
+
+    static Variable undefined() {
+        return new Variable.Undefined();
+    }
+
+    record Undefined() implements Variable {
+    }
+
+    record Defined(Type type) implements Variable {
+    }
+}
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java
index 21ebfbc3..1f5d82ee 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerAssignTests.java
@@ -24,7 +24,7 @@ public class TypeCheckerAssignTests {
         var untyped = Untyped.assign(Untyped.targetVariable("x"), Untyped.stringLiteral("hello"));
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.defined(Types.STRING))
+                Map.entry("x", Variable.defined(Types.STRING))
             ));
 
         var typed = typeCheckFunctionStatement(untyped, context);
@@ -40,7 +40,7 @@ public class TypeCheckerAssignTests {
         var untyped = Untyped.assign(Untyped.targetVariable("x"), Untyped.stringLiteral("hello"));
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.defined(Types.INT))
+                Map.entry("x", Variable.defined(Types.INT))
             ));
 
         var error = assertThrows(
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java
index 33cfda12..59576069 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerCallTests.java
@@ -307,7 +307,7 @@ public class TypeCheckerCallTests {
             .build();
         var context = TypeCheckerContext.EMPTY
             .enterFunction(
-                P.map(Map.entry("f", TypeCheckerContext.defined(functionType))),
+                P.map(Map.entry("f", Variable.defined(functionType))),
                 Effects.IO,
                 Types.UNIT
             );
@@ -334,7 +334,7 @@ public class TypeCheckerCallTests {
             .build();
         var context = TypeCheckerContext.EMPTY
             .enterFunction(
-                P.map(Map.entry("f", TypeCheckerContext.defined(functionType))),
+                P.map(Map.entry("f", Variable.defined(functionType))),
                 Effects.NONE,
                 Types.UNIT
             );
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
index a9198b86..3c622348 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerContextTests.java
@@ -19,21 +19,21 @@ public class TypeCheckerContextTests {
     public void givenVariableIsUndefinedWhenVariableIsDefinedThenVariableHasTypeSet() {
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.undefined()),
-                Map.entry("y", TypeCheckerContext.undefined())
+                Map.entry("x", Variable.undefined()),
+                Map.entry("y", Variable.undefined())
             ));
 
         context = context.define("x", Types.STRING, Sources.NULL);
         var result = context.runtimeLookup("x", Sources.NULL);
 
-        assertThat(result.value(), isOptionalOf(equalTo(TypeCheckerContext.defined(Types.STRING))));
+        assertThat(result.value(), isOptionalOf(equalTo(Variable.defined(Types.STRING))));
     }
 
     @Test
     public void givenVariableIsUnknownWhenVariableIsDefinedThenErrorIsThrown() {
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("y", TypeCheckerContext.undefined())
+                Map.entry("y", Variable.undefined())
             ));
 
         var error = assertThrows(
@@ -48,7 +48,7 @@ public class TypeCheckerContextTests {
     public void givenVariableIsDefinedWhenVariableIsDefinedThenErrorIsThrown() {
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.defined(Types.STRING))
+                Map.entry("x", Variable.defined(Types.STRING))
             ));
 
         var error = assertThrows(
@@ -63,7 +63,7 @@ public class TypeCheckerContextTests {
     public void givenVariableIsBoundInOuterScopeWhenVariableIsDefinedThenErrorIsThrown() {
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.undefined())
+                Map.entry("x", Variable.undefined())
             ))
             .enterNamespace(P.map());
 
@@ -79,23 +79,23 @@ public class TypeCheckerContextTests {
     public void definingVariableOnlyAffectsTopMostLexicalContext() {
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.undefined()),
-                Map.entry("y", TypeCheckerContext.undefined())
+                Map.entry("x", Variable.undefined()),
+                Map.entry("y", Variable.undefined())
             ));
 
         context = context.enterBlock(P.map(
-            Map.entry("x", TypeCheckerContext.undefined())
+            Map.entry("x", Variable.undefined())
         ));
         context = context.define("x", Types.STRING, Sources.NULL);
         assertThat(
             context.runtimeLookup("x", Sources.NULL).value(),
-            isOptionalOf(equalTo(TypeCheckerContext.defined(Types.STRING)))
+            isOptionalOf(equalTo(Variable.defined(Types.STRING)))
         );
 
         context = context.exit();
         assertThat(
             context.runtimeLookup("x", Sources.NULL).value(),
-            isOptionalOf(equalTo(TypeCheckerContext.undefined()))
+            isOptionalOf(equalTo(Variable.undefined()))
         );
     }
 
@@ -104,7 +104,7 @@ public class TypeCheckerContextTests {
         var context = TypeCheckerContext.EMPTY
             .enterBlock(P.map())
             .enterBlock(P.map(
-                Map.entry("x", TypeCheckerContext.undefined())
+                Map.entry("x", Variable.undefined())
             ))
             .enterBlock(P.map())
             .enterBlock(P.map());
diff --git a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerIfTests.java b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerIfTests.java
index a52fdfac..69ae78af 100644
--- a/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerIfTests.java
+++ b/src/test/java/org/shedlang/compiler/typechecker/TypeCheckerIfTests.java
@@ -129,7 +129,7 @@ public class TypeCheckerIfTests {
         );
         var context = TypeCheckerContext.EMPTY
             .enterNamespace(P.map(
-                Map.entry("x", TypeCheckerContext.defined(Types.STRING))
+                Map.entry("x", Variable.defined(Types.STRING))
             ));
 
         var result = TypeChecker.typeCheckExpression(untyped, context);