Allow reading of methods without body

2 files changed, 25 insertions, 14 deletions

diff --git a/src/main/java/org/zwobble/couscous/ast/MethodNode.java b/src/main/java/org/zwobble/couscous/ast/MethodNode.java
index dd970c5..967b2b1 100644
--- a/src/main/java/org/zwobble/couscous/ast/MethodNode.java
+++ b/src/main/java/org/zwobble/couscous/ast/MethodNode.java
@@ -6,6 +6,7 @@ import org.zwobble.couscous.ast.visitors.NodeTransformer;
 import org.zwobble.couscous.values.UnitValue;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.function.Function;
 
 import static org.zwobble.couscous.util.ExtraLists.eagerMap;
@@ -22,6 +23,7 @@ public class MethodNode implements CallableNode {
         private final ImmutableList.Builder<AnnotationNode> annotations =
             ImmutableList.builder();
         private boolean isStatic = false;
+        private boolean isAbstract = false;
         private final String name;
         private final ImmutableList.Builder<FormalArgumentNode> arguments =
             ImmutableList.builder();
@@ -42,6 +44,11 @@ public class MethodNode implements CallableNode {
             this.isStatic = isStatic;
             return this;
         }
+
+        public Builder isAbstract() {
+            this.isAbstract = true;
+            return this;
+        }
         
         public Builder argument(FormalArgumentNode argument) {
             arguments.add(argument);
@@ -75,7 +82,7 @@ public class MethodNode implements CallableNode {
                 name,
                 arguments.build(),
                 returnType,
-                body.build());
+                isAbstract ? Optional.empty() : Optional.of(body.build()));
         }
     }
     
@@ -85,7 +92,7 @@ public class MethodNode implements CallableNode {
         String name,
         List<FormalArgumentNode> arguments,
         TypeName returnType,
-        List<StatementNode> body)
+        Optional<List<StatementNode>> body)
     {
         return new MethodNode(annotations, isStatic, name, arguments, returnType, body);
     }
@@ -95,7 +102,7 @@ public class MethodNode implements CallableNode {
     private final String name;
     private final List<FormalArgumentNode> arguments;
     private final TypeName returnType;
-    private final List<StatementNode> body;
+    private final Optional<List<StatementNode>> body;
     
     private MethodNode(
         List<AnnotationNode> annotations,
@@ -103,7 +110,7 @@ public class MethodNode implements CallableNode {
         String name,
         List<FormalArgumentNode> arguments,
         TypeName returnType,
-        List<StatementNode> body)
+        Optional<List<StatementNode>> body)
     {
         this.annotations = annotations;
         this.isStatic = isStatic;
@@ -134,7 +141,7 @@ public class MethodNode implements CallableNode {
     }
     
     public List<StatementNode> getBody() {
-        return body;
+        return body.get();
     }
 
     public MethodSignature signature() {
@@ -145,7 +152,7 @@ public class MethodNode implements CallableNode {
     }
 
     public MethodNode mapBody(Function<List<StatementNode>, List<StatementNode>> function) {
-        return new MethodNode(annotations, isStatic, name, arguments, returnType, function.apply(body));
+        return new MethodNode(annotations, isStatic, name, arguments, returnType, body.map(function));
     }
 
     @Override
@@ -160,7 +167,7 @@ public class MethodNode implements CallableNode {
             transformer.transformMethodName(signature()),
             transformer.transformFormalArguments(arguments),
             transformer.transform(returnType),
-            transformer.transformStatements(body));
+            body.map(transformer::transformStatements));
     }
 
     @Override
diff --git a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
index 4eb7c7d..ccc37e0 100644
--- a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
+++ b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
@@ -114,7 +114,7 @@ public class JavaReader {
             functionalInterfaceMethod.getName(),
             lambda.getFormalArguments(),
             typeOf(functionalInterfaceMethod.getReturnType()),
-            lambda.getBody());
+            Optional.of(lambda.getBody()));
 
         return new AnonymousClass(
             superTypesAndSelf(functionalInterfaceMethod.getDeclaringClass()),
@@ -286,12 +286,12 @@ public class JavaReader {
         List<AnnotationNode> annotations = readAnnotations(method);
         Optional<TypeName> returnType = Optional.ofNullable(method.getReturnType2())
             .map(JavaTypes::typeOf);
-        List<StatementNode> body = readBody(scope, method, returnType);
+        Optional<List<StatementNode>> body = readBody(scope, method, returnType);
 
         if (method.isConstructor()) {
             builder.constructor(constructor(
                 formalArguments,
-                body));
+                body.get()));
         } else {
             builder.addMethod(MethodNode.method(
                 annotations,
@@ -317,10 +317,14 @@ public class JavaReader {
         return eagerMap(parameters, parameter -> JavaVariableDeclarationReader.read(scope, parameter));
     }
 
-    private List<StatementNode> readBody(Scope scope, MethodDeclaration method, Optional<TypeName> returnType) {
-        @SuppressWarnings("unchecked")
-        List<Statement> statements = method.getBody().statements();
-        return readStatements(scope, statements, returnType);
+    private Optional<List<StatementNode>> readBody(Scope scope, MethodDeclaration method, Optional<TypeName> returnType) {
+        if (method.getBody() == null) {
+            return Optional.empty();
+        } else {
+            @SuppressWarnings("unchecked")
+            List<Statement> statements = method.getBody().statements();
+            return Optional.of(readStatements(scope, statements, returnType));
+        }
     }
 
     List<StatementNode> readStatement(Scope scope, Statement statement) {