From 4054a250df414bb2c756d12b133aaaa8cd6bbce3 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 20 Oct 2015 19:00:49 +0100
Subject: Java: read formal method arguments

---
 .../java/org/zwobble/couscous/ast/ClassNodeBuilder.java |  8 ++++++++
 .../org/zwobble/couscous/frontends/java/JavaReader.java | 13 +++++++++++++
 .../couscous/tests/frontends/java/JavaReaderTests.java  | 17 +++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/src/main/java/org/zwobble/couscous/ast/ClassNodeBuilder.java b/src/main/java/org/zwobble/couscous/ast/ClassNodeBuilder.java
index b4ddad9..7466f07 100644
--- a/src/main/java/org/zwobble/couscous/ast/ClassNodeBuilder.java
+++ b/src/main/java/org/zwobble/couscous/ast/ClassNodeBuilder.java
@@ -5,6 +5,9 @@ import java.util.function.Function;
 
 import com.google.common.collect.ImmutableList;
 
+import static org.zwobble.couscous.ast.FormalArgumentNode.formalArg;
+import static org.zwobble.couscous.ast.VariableDeclaration.var;
+
 public class ClassNodeBuilder {
     private final TypeName name;
     private final ImmutableList.Builder<FieldDeclarationNode> fields;
@@ -85,6 +88,11 @@ public class ClassNodeBuilder {
             return ThisReferenceNode.thisReference(name);
         }
         
+        public MethodBuilder<T> argument(String id, String name, TypeName type) {
+            arguments.add(formalArg(var(id, name, type)));
+            return this;
+        }
+        
         public MethodBuilder<T> argument(FormalArgumentNode argument) {
             arguments.add(argument);
             return this;
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 b8a3b62..22d42ab 100644
--- a/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
+++ b/src/main/java/org/zwobble/couscous/frontends/java/JavaReader.java
@@ -22,6 +22,7 @@ import org.eclipse.jdt.core.dom.Modifier;
 import org.eclipse.jdt.core.dom.NumberLiteral;
 import org.eclipse.jdt.core.dom.ReturnStatement;
 import org.eclipse.jdt.core.dom.SimpleName;
+import org.eclipse.jdt.core.dom.SingleVariableDeclaration;
 import org.eclipse.jdt.core.dom.Statement;
 import org.eclipse.jdt.core.dom.StringLiteral;
 import org.eclipse.jdt.core.dom.ThisExpression;
@@ -102,6 +103,14 @@ public class JavaReader {
             method.getName().getIdentifier(),
             true,
             builder -> {
+                for (Object parameterObject : method.parameters()) {
+                    val parameter = (SingleVariableDeclaration)parameterObject;
+                    builder.argument(
+                        parameter.resolveBinding().getKey(),
+                        parameter.getName().getIdentifier(),
+                        typeOf(parameter.resolveBinding()));
+                }
+                
                 for (Object statement : method.getBody().statements()) {
                     for (StatementNode intermediateStatement : readStatement((Statement)statement)) {
                         builder.statement(intermediateStatement);                        
@@ -282,6 +291,10 @@ public class JavaReader {
         return typeOf(expression.resolveTypeBinding());
     }
 
+    private static TypeName typeOf(IVariableBinding variableBinding) {
+        return typeOf(variableBinding.getType());
+    }
+
     private static TypeName typeOf(ITypeBinding typeBinding) {
         return TypeName.of(typeBinding.getQualifiedName());
     }
diff --git a/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java b/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
index 98a6138..4a92f1b 100644
--- a/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/frontends/java/JavaReaderTests.java
@@ -180,6 +180,23 @@ public class JavaReaderTests {
             returnNode.getValue());
     }
     
+    @Test
+    public void canDeclareAndReferenceArguments() {
+        val classNode = readClass(
+            "public String identity(int value) {" +
+            "    return value;" +
+            "}");
+        
+        val method = classNode.getMethods().get(0);
+        val argument = method.getArguments().get(0);
+        assertEquals("value", argument.getName());
+        assertEquals(TypeName.of("int"), argument.getType());
+        assertEquals(1, method.getArguments().size());
+        
+        val returnNode = (ReturnNode)method.getBody().get(0);
+        assertEquals(reference(argument), returnNode.getValue());
+    }
+    
     @Test
     public void canReadExpressionStatements() {
         assertEquals(
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