Add support for adding strings

4 files changed, 32 insertions, 7 deletions

diff --git a/src/main/java/org/zwobble/couscous/backends/python/PrimitiveMethods.java b/src/main/java/org/zwobble/couscous/backends/python/PrimitiveMethods.java
index cc2ec06..b370f6d 100644
--- a/src/main/java/org/zwobble/couscous/backends/python/PrimitiveMethods.java
+++ b/src/main/java/org/zwobble/couscous/backends/python/PrimitiveMethods.java
@@ -35,6 +35,9 @@ public class PrimitiveMethods {
             
             .put("substring", (receiver, arguments) ->
                 pythonGetSlice(receiver, arguments))
+
+            .put("add", (receiver, arguments) ->
+                PythonBinaryOperation.pythonAdd(receiver, arguments.get(0)))
             
             .build();
     
diff --git a/src/main/java/org/zwobble/couscous/backends/python/ast/PythonBinaryOperation.java b/src/main/java/org/zwobble/couscous/backends/python/ast/PythonBinaryOperation.java
index 1fc87c3..fb33626 100644
--- a/src/main/java/org/zwobble/couscous/backends/python/ast/PythonBinaryOperation.java
+++ b/src/main/java/org/zwobble/couscous/backends/python/ast/PythonBinaryOperation.java
@@ -6,6 +6,10 @@ public class PythonBinaryOperation implements PythonExpressionNode {
     public static PythonExpressionNode pythonIs(PythonExpressionNode left, PythonExpressionNode right) {
         return new PythonBinaryOperation("is", left, right);
     }
+
+    public static PythonExpressionNode pythonAdd(PythonExpressionNode left, PythonExpressionNode right) {
+        return new PythonBinaryOperation("+", left, right);
+    }
     
     private final String operator;
     private final PythonExpressionNode left;
diff --git a/src/main/java/org/zwobble/couscous/interpreter/values/StringInterpreterValue.java b/src/main/java/org/zwobble/couscous/interpreter/values/StringInterpreterValue.java
index bbc9f6c..b19d849 100644
--- a/src/main/java/org/zwobble/couscous/interpreter/values/StringInterpreterValue.java
+++ b/src/main/java/org/zwobble/couscous/interpreter/values/StringInterpreterValue.java
@@ -1,20 +1,33 @@
 package org.zwobble.couscous.interpreter.values;
 
-import java.util.Optional;
 import org.zwobble.couscous.interpreter.NoSuchField;
 import org.zwobble.couscous.values.IntegerValue;
 import org.zwobble.couscous.values.PrimitiveValue;
 import org.zwobble.couscous.values.PrimitiveValues;
 import org.zwobble.couscous.values.StringValue;
-import static java.util.Arrays.asList;
+
+import java.util.Optional;
+
 import static org.zwobble.couscous.util.ExtraLists.list;
 
 public final class StringInterpreterValue implements InterpreterValue {
-    public static final ConcreteType TYPE = ConcreteType.builder(StringInterpreterValue.class, StringValue.REF).method("length", list(), (environment, arguments) -> new IntegerInterpreterValue(arguments.getReceiver().value.length())).method("substring", list(IntegerValue.REF, IntegerValue.REF), (environment, arguments) -> {
-        IntegerInterpreterValue startIndex = (IntegerInterpreterValue)arguments.get(0);
-        IntegerInterpreterValue endIndex = (IntegerInterpreterValue)arguments.get(1);
-        return new StringInterpreterValue(arguments.getReceiver().value.substring(startIndex.getValue(), endIndex.getValue()));
-    }).build();
+    public static final ConcreteType TYPE = ConcreteType.builder(StringInterpreterValue.class, StringValue.REF)
+        .method("length", list(), (environment, arguments) ->
+            new IntegerInterpreterValue(arguments.getReceiver().value.length()))
+
+        .method("substring", list(IntegerValue.REF, IntegerValue.REF), (environment, arguments) -> {
+            IntegerInterpreterValue startIndex = (IntegerInterpreterValue)arguments.get(0);
+            IntegerInterpreterValue endIndex = (IntegerInterpreterValue)arguments.get(1);
+            return new StringInterpreterValue(arguments.getReceiver().value.substring(startIndex.getValue(), endIndex.getValue()));
+        })
+
+        .method("add", list(StringValue.REF), (environment, arguments) -> {
+            StringInterpreterValue right = (StringInterpreterValue)arguments.get(0);
+            return new StringInterpreterValue(arguments.getReceiver().value + right.value);
+        })
+
+        .build();
+
     private final String value;
     
     @Override
diff --git a/src/test/java/org/zwobble/couscous/tests/CompilerTests.java b/src/test/java/org/zwobble/couscous/tests/CompilerTests.java
index ea12bc4..e8957f7 100644
--- a/src/test/java/org/zwobble/couscous/tests/CompilerTests.java
+++ b/src/test/java/org/zwobble/couscous/tests/CompilerTests.java
@@ -144,6 +144,11 @@ public abstract class CompilerTests {
                 list()));
     }
 
+    @Test
+    public void stringAdd() throws Exception {
+        assertEquals(value("42"), evalExpression("String", "\"4\" + \"2\""));
+    }
+
     private PrimitiveValue execTestProgram(
         String directoryName,
         TypeName type,