Allow arguments to be passed to methods

7 files changed, 34 insertions, 8 deletions

diff --git a/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java b/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
index 55249a3..09058fc 100644
--- a/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
+++ b/src/main/java/org/zwobble/couscous/ast/MethodCallNode.java
@@ -1,16 +1,21 @@
 package org.zwobble.couscous.ast;
 
+import java.util.List;
+
 import org.zwobble.couscous.ast.visitors.ExpressionNodeVisitor;
 
+import static java.util.Arrays.asList;
+
 import lombok.Value;
 
 @Value
 public class MethodCallNode implements ExpressionNode {
     ExpressionNode receiver;
     String methodName;
+    List<ExpressionNode> arguments;
     
-    public static MethodCallNode methodCall(ExpressionNode receiver, String methodName) {
-        return new MethodCallNode(receiver, methodName);
+    public static MethodCallNode methodCall(ExpressionNode receiver, String methodName, ExpressionNode... arguments) {
+        return new MethodCallNode(receiver, methodName, asList(arguments));
     }
     
     @Override
diff --git a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
index 54a1f60..7a57137 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/Evaluator.java
@@ -1,5 +1,7 @@
 package org.zwobble.couscous.interpreter;
 
+import java.util.stream.Collectors;
+
 import org.zwobble.couscous.ast.Assignment;
 import org.zwobble.couscous.ast.ExpressionNode;
 import org.zwobble.couscous.ast.LiteralNode;
@@ -59,7 +61,11 @@ public class Evaluator implements ExpressionNodeVisitor<InterpreterValue> {
     @Override
     public InterpreterValue visit(MethodCallNode methodCall) {
         val receiver = eval(methodCall.getReceiver());
+        val arguments = methodCall.getArguments()
+            .stream()
+            .map(argument -> eval(argument))
+            .collect(Collectors.toList());
         // TODO: handle missing methods
-        return receiver.callMethod(methodCall.getMethodName());
+        return receiver.callMethod(methodCall.getMethodName(), arguments);
     }
 }
diff --git a/src/main/java/org/zwobble/couscous/values/BooleanValue.java b/src/main/java/org/zwobble/couscous/values/BooleanValue.java
index e6998df..dd8cd39 100644
--- a/src/main/java/org/zwobble/couscous/values/BooleanValue.java
+++ b/src/main/java/org/zwobble/couscous/values/BooleanValue.java
@@ -1,5 +1,7 @@
 package org.zwobble.couscous.values;
 
+import java.util.List;
+
 import lombok.AccessLevel;
 import lombok.Getter;
 import lombok.Value;
@@ -14,7 +16,7 @@ public class BooleanValue implements InterpreterValue {
     }
 
     @Override
-    public InterpreterValue callMethod(String methodName) {
+    public InterpreterValue callMethod(String methodName, List<InterpreterValue> arguments) {
         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 2bb28d8..acc0c56 100644
--- a/src/main/java/org/zwobble/couscous/values/IntegerValue.java
+++ b/src/main/java/org/zwobble/couscous/values/IntegerValue.java
@@ -1,5 +1,7 @@
 package org.zwobble.couscous.values;
 
+import java.util.List;
+
 import lombok.Value;
 
 @Value
@@ -7,7 +9,7 @@ public class IntegerValue implements InterpreterValue {
     int value;
 
     @Override
-    public InterpreterValue callMethod(String methodName) {
+    public InterpreterValue callMethod(String methodName, List<InterpreterValue> arguments) {
         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 7ffebbc..6162aaa 100644
--- a/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
+++ b/src/main/java/org/zwobble/couscous/values/InterpreterValue.java
@@ -1,5 +1,7 @@
 package org.zwobble.couscous.values;
 
+import java.util.List;
+
 public interface InterpreterValue {
-    InterpreterValue callMethod(String methodName);
+    InterpreterValue callMethod(String methodName, List<InterpreterValue> arguments);
 }
diff --git a/src/main/java/org/zwobble/couscous/values/StringValue.java b/src/main/java/org/zwobble/couscous/values/StringValue.java
index 0e3f626..3a1a13d 100644
--- a/src/main/java/org/zwobble/couscous/values/StringValue.java
+++ b/src/main/java/org/zwobble/couscous/values/StringValue.java
@@ -1,15 +1,22 @@
 package org.zwobble.couscous.values;
 
+import java.util.List;
+
 import lombok.Value;
+import lombok.val;
 
 @Value
 public class StringValue implements InterpreterValue {
     String value;
 
     @Override
-    public InterpreterValue callMethod(String methodName) {
+    public InterpreterValue callMethod(String methodName, List<InterpreterValue> arguments) {
         if (methodName == "length") {
             return new IntegerValue(value.length());
+        } else if (methodName == "substring") {
+            val startIndex = (IntegerValue)arguments.get(0);
+            val endIndex = (IntegerValue)arguments.get(1);
+            return new StringValue(value.substring(startIndex.getValue(), endIndex.getValue()));
         } 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 45178dd..030fb03 100644
--- a/src/main/java/org/zwobble/couscous/values/UnitValue.java
+++ b/src/main/java/org/zwobble/couscous/values/UnitValue.java
@@ -1,5 +1,7 @@
 package org.zwobble.couscous.values;
 
+import java.util.List;
+
 import lombok.ToString;
 
 @ToString
@@ -10,7 +12,7 @@ public class UnitValue implements InterpreterValue {
     }
 
     @Override
-    public InterpreterValue callMethod(String methodName) {
+    public InterpreterValue callMethod(String methodName, List<InterpreterValue> arguments) {
         throw new UnsupportedOperationException();
     }
 }