From cf12234c6f3d022c5e0882a26e6cfd39b45e0abf Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Tue, 29 Sep 2015 23:43:45 +0100
Subject: Add builtin method calls with no arguments

---
 src/main/java/org/zwobble/couscous/ast/CallNode.java |  5 -----
 .../org/zwobble/couscous/ast/MethodCallNode.java     | 20 ++++++++++++++++++++
 .../couscous/ast/visitors/ExpressionNodeVisitor.java |  2 ++
 .../org/zwobble/couscous/interpreter/Evaluator.java  |  8 ++++++++
 .../org/zwobble/couscous/values/BooleanValue.java    |  5 +++++
 .../org/zwobble/couscous/values/IntegerValue.java    |  5 +++++
 .../zwobble/couscous/values/InterpreterValue.java    |  2 +-
 .../org/zwobble/couscous/values/StringValue.java     |  9 +++++++++
 .../java/org/zwobble/couscous/values/UnitValue.java  |  5 +++++
 .../couscous/tests/interpreter/EvaluatorTests.java   |  8 ++++++++
 .../couscous/tests/interpreter/InterpreterTests.java | 16 ++++++++--------
 11 files changed, 71 insertions(+), 14 deletions(-)
 delete mode 100644 src/main/java/org/zwobble/couscous/ast/CallNode.java
 create mode 100644 src/main/java/org/zwobble/couscous/ast/MethodCallNode.java

(limited to 'src')

diff --git a/src/main/java/org/zwobble/couscous/ast/CallNode.java b/src/main/java/org/zwobble/couscous/ast/CallNode.java
deleted file mode 100644
index d71c891..0000000
--- a/src/main/java/org/zwobble/couscous/ast/CallNode.java
+++ /dev/null
@@ -1,5 +0,0 @@
-package org.zwobble.couscous.ast;
-
-public class CallNode {
-
-}
diff --git a/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java b/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
new file mode 100644
index 0000000..55249a3
--- /dev/null
+++ b/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
@@ -0,0 +1,20 @@
+package org.zwobble.couscous.ast;
+
+import org.zwobble.couscous.ast.visitors.ExpressionNodeVisitor;
+
+import lombok.Value;
+
+@Value
+public class MethodCallNode implements ExpressionNode {
+    ExpressionNode receiver;
+    String methodName;
+    
+    public static MethodCallNode methodCall(ExpressionNode receiver, String methodName) {
+        return new MethodCallNode(receiver, methodName);
+    }
+    
+    @Override
+    public <T> T accept(ExpressionNodeVisitor<T> visitor) {
+        return visitor.visit(this);
+    }
+}
diff --git a/src/main/java/org/zwobble/couscous/ast/visitors/ExpressionNodeVisitor.java b/src/main/java/org/zwobble/couscous/ast/visitors/ExpressionNodeVisitor.java
index 27692e3..f083625 100644
--- a/src/main/java/org/zwobble/couscous/ast/visitors/ExpressionNodeVisitor.java
+++ b/src/main/java/org/zwobble/couscous/ast/visitors/ExpressionNodeVisitor.java
@@ -2,6 +2,7 @@ package org.zwobble.couscous.ast.visitors;
 
 import org.zwobble.couscous.ast.Assignment;
 import org.zwobble.couscous.ast.LiteralNode;
+import org.zwobble.couscous.ast.MethodCallNode;
 import org.zwobble.couscous.ast.TernaryConditionalNode;
 import org.zwobble.couscous.ast.VariableReferenceNode;
 
@@ -10,4 +11,5 @@ public interface ExpressionNodeVisitor<T> {
     T visit(VariableReferenceNode variableReference);
     T visit(Assignment assignment);
     T visit(TernaryConditionalNode ternaryConditional);
+    T visit(MethodCallNode methodCall);
 }
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
index 232441c..54a1f60 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
@@ -3,6 +3,7 @@ package org.zwobble.couscous.interpreter;
 import org.zwobble.couscous.ast.Assignment;
 import org.zwobble.couscous.ast.ExpressionNode;
 import org.zwobble.couscous.ast.LiteralNode;
+import org.zwobble.couscous.ast.MethodCallNode;
 import org.zwobble.couscous.ast.TernaryConditionalNode;
 import org.zwobble.couscous.ast.VariableReferenceNode;
 import org.zwobble.couscous.ast.visitors.ExpressionNodeVisitor;
@@ -54,4 +55,11 @@ public class Evaluator implements ExpressionNodeVisitor<InterpreterValue> {
             : ternaryConditional.getIfFalse();
         return eval(branch);
     }
+
+    @Override
+    public InterpreterValue visit(MethodCallNode methodCall) {
+        val receiver = eval(methodCall.getReceiver());
+        // TODO: handle missing methods
+        return receiver.callMethod(methodCall.getMethodName());
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/BooleanValue.java b/src/main/java/org/zwobble/couscous/values/BooleanValue.java
index 6d016e6..e6998df 100644
--- a/src/main/java/org/zwobble/couscous/values/BooleanValue.java
+++ b/src/main/java/org/zwobble/couscous/values/BooleanValue.java
@@ -12,4 +12,9 @@ public class BooleanValue implements InterpreterValue {
     public boolean getValue() {
         return value;
     }
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/IntegerValue.java b/src/main/java/org/zwobble/couscous/values/IntegerValue.java
index 062d137..2bb28d8 100644
--- a/src/main/java/org/zwobble/couscous/values/IntegerValue.java
+++ b/src/main/java/org/zwobble/couscous/values/IntegerValue.java
@@ -5,4 +5,9 @@ import lombok.Value;
 @Value
 public class IntegerValue implements InterpreterValue {
     int value;
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/InterpreterValue.java b/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
index 64b0e91..7ffebbc 100644
--- a/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
+++ b/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
@@ -1,5 +1,5 @@
 package org.zwobble.couscous.values;
 
 public interface InterpreterValue {
-
+    InterpreterValue callMethod(String methodName);
 }
diff --git a/src/main/java/org/zwobble/couscous/values/StringValue.java b/src/main/java/org/zwobble/couscous/values/StringValue.java
index 1478d41..0e3f626 100644
--- a/src/main/java/org/zwobble/couscous/values/StringValue.java
+++ b/src/main/java/org/zwobble/couscous/values/StringValue.java
@@ -5,4 +5,13 @@ import lombok.Value;
 @Value
 public class StringValue implements InterpreterValue {
     String value;
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        if (methodName == "length") {
+            return new IntegerValue(value.length());
+        } else {
+            throw new UnsupportedOperationException();
+        }
+    }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/UnitValue.java b/src/main/java/org/zwobble/couscous/values/UnitValue.java
index 1cf9dc7..45178dd 100644
--- a/src/main/java/org/zwobble/couscous/values/UnitValue.java
+++ b/src/main/java/org/zwobble/couscous/values/UnitValue.java
@@ -8,4 +8,9 @@ public class UnitValue implements InterpreterValue {
     
     private UnitValue() {
     }
+
+    @Override
+    public InterpreterValue callMethod(String methodName) {
+        throw new UnsupportedOperationException();
+    }
 }
diff --git a/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java b/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java
index dbf20f8..6aee7d5 100644
--- a/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/interpreter/EvaluatorTests.java
@@ -13,6 +13,7 @@ import com.google.common.collect.ImmutableMap;
 import static org.junit.Assert.assertEquals;
 import static org.zwobble.couscous.ast.Assignment.assign;
 import static org.zwobble.couscous.ast.LiteralNode.literal;
+import static org.zwobble.couscous.ast.MethodCallNode.methodCall;
 import static org.zwobble.couscous.interpreter.Evaluator.eval;
 import static org.zwobble.couscous.tests.util.ExtraAsserts.assertThrows;
 
@@ -49,6 +50,13 @@ public class EvaluatorTests {
         assertEquals(new ConditionMustBeBoolean(new IntegerValue(1)), exception);
     }
     
+    @Test
+    public void canCallMethodWithNoArgumentsOnBuiltin() {
+        val result = eval(emptyEnvironment(),
+            methodCall(literal("hello"), "length"));
+        assertEquals(new IntegerValue(5), result);
+    }
+    
     private static Environment emptyEnvironment() {
         return new Environment(ImmutableMap.of());
     }
diff --git a/src/test/java/org/zwobble/couscous/tests/interpreter/InterpreterTests.java b/src/test/java/org/zwobble/couscous/tests/interpreter/InterpreterTests.java
index 54abd8a..bfdadf8 100644
--- a/src/test/java/org/zwobble/couscous/tests/interpreter/InterpreterTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/interpreter/InterpreterTests.java
@@ -28,6 +28,14 @@ import static org.zwobble.couscous.values.UnitValue.UNIT;
 import lombok.val;
 
 public class InterpreterTests {
+    @Test
+    public void methodWithNoStatementsReturnsUnit() {
+        val method = staticMethod("hello");
+        val result = runMethod(method);
+        
+        assertEquals(UNIT, result);
+    }
+    
     @Test
     public void canReturnLiteralValue() {
         val method = staticMethod("hello")
@@ -69,14 +77,6 @@ public class InterpreterTests {
         
         assertEquals(new StringValue("[updated value]"), result);
     }
-    
-    @Test
-    public void methodWithNoStatementsReturnsUnit() {
-        val method = staticMethod("hello");
-        val result = runMethod(method);
-        
-        assertEquals(UNIT, result);
-    }
 
     private InterpreterValue runMethod(MethodNode.MethodNodeBuilder methodBuilder, InterpreterValue... arguments) {
         val method = methodBuilder.build();
-- 
cgit v1.2.3