From c58796cf60fcb109ab56ae2b1c0872c58771f3e1 Mon Sep 17 00:00:00 2001
From: Michael Williamson <mike@zwobble.org>
Date: Wed, 30 Mar 2016 19:58:01 +0100
Subject: Add code generation for Python backend for arrays

---
 .../backends/python/PythonCodeGenerator.java       | 10 ++--
 .../backends/python/PythonCodeGeneratorTests.java  | 62 ++++++++++++++++++++++
 2 files changed, 69 insertions(+), 3 deletions(-)
 create mode 100644 src/test/java/org/zwobble/couscous/tests/backends/python/PythonCodeGeneratorTests.java

diff --git a/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java b/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java
index 1ed223e..9aa679a 100644
--- a/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java
+++ b/src/main/java/org/zwobble/couscous/backends/python/PythonCodeGenerator.java
@@ -23,6 +23,7 @@ import java.util.stream.Stream;
 import static com.google.common.collect.Iterables.filter;
 import static com.google.common.collect.Iterables.transform;
 import static com.google.common.collect.Iterators.singletonIterator;
+import static org.zwobble.couscous.backends.python.ast.PythonArrayNode.pythonArray;
 import static org.zwobble.couscous.types.Types.erasure;
 import static org.zwobble.couscous.backends.python.ast.PythonAssignmentNode.pythonAssignment;
 import static org.zwobble.couscous.backends.python.ast.PythonAttributeAccessNode.pythonAttributeAccess;
@@ -42,6 +43,7 @@ import static org.zwobble.couscous.backends.python.ast.PythonVariableReferenceNo
 import static org.zwobble.couscous.backends.python.ast.PythonWhileNode.pythonWhile;
 import static org.zwobble.couscous.backends.python.ast.visitors.PythonExpressionStatement.pythonExpressionStatement;
 import static org.zwobble.couscous.util.Casts.tryCast;
+import static org.zwobble.couscous.util.ExtraLists.eagerMap;
 import static org.zwobble.couscous.util.ExtraLists.list;
 
 public class PythonCodeGenerator {
@@ -225,7 +227,7 @@ public class PythonCodeGenerator {
         }
     }
 
-    private static PythonExpressionNode generateExpression(ExpressionNode expression) {
+    public static PythonExpressionNode generateExpression(ExpressionNode expression) {
         return expression.accept(EXPRESSION_GENERATOR);
     }
 
@@ -251,8 +253,10 @@ public class PythonCodeGenerator {
         }
 
         @Override
-        public PythonExpressionNode visit(ArrayNode arrayNode) {
-            throw new UnsupportedOperationException();
+        public PythonExpressionNode visit(ArrayNode array) {
+            return pythonArray(eagerMap(
+                array.getElements(),
+                PythonCodeGenerator::generateExpression));
         }
 
         @Override
diff --git a/src/test/java/org/zwobble/couscous/tests/backends/python/PythonCodeGeneratorTests.java b/src/test/java/org/zwobble/couscous/tests/backends/python/PythonCodeGeneratorTests.java
new file mode 100644
index 0000000..1b043bc
--- /dev/null
+++ b/src/test/java/org/zwobble/couscous/tests/backends/python/PythonCodeGeneratorTests.java
@@ -0,0 +1,62 @@
+package org.zwobble.couscous.tests.backends.python;
+
+import org.hamcrest.FeatureMatcher;
+import org.hamcrest.Matcher;
+import org.junit.Test;
+import org.zwobble.couscous.backends.python.PythonCodeGenerator;
+import org.zwobble.couscous.backends.python.ast.PythonArrayNode;
+import org.zwobble.couscous.backends.python.ast.PythonExpressionNode;
+import org.zwobble.couscous.backends.python.ast.PythonStringLiteralNode;
+import org.zwobble.couscous.types.Types;
+
+import java.util.List;
+import java.util.function.Function;
+
+import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.*;
+import static org.zwobble.couscous.ast.ArrayNode.array;
+import static org.zwobble.couscous.ast.LiteralNode.literal;
+import static org.zwobble.couscous.util.ExtraLists.list;
+
+public class PythonCodeGeneratorTests {
+    @Test
+    public void arrayIsConvertedToPythonList() {
+        assertThat(
+            PythonCodeGenerator.generateExpression(array(Types.STRING, list(
+                literal("one"),
+                literal("two")))),
+            isPythonList(list(isPythonLiteral("one"), isPythonLiteral("two"))));
+    }
+
+    private <T> Matcher<PythonExpressionNode> isPythonLiteral(String value) {
+        return isA(PythonStringLiteralNode.class, hasFeature(
+            "value",
+            node -> node.getValue(),
+            equalTo(value)));
+    }
+
+    private static <T, U> Matcher<T> isA(Class<U> type, Matcher<? super U> downcastMatcher) {
+        return allOf(instanceOf(type), (Matcher<? super T>) downcastMatcher);
+    }
+
+    private static Matcher<PythonExpressionNode> isPythonList(
+        List<Matcher<? super PythonExpressionNode>> expectedElements)
+    {
+        return isA(PythonArrayNode.class, hasFeature(
+            "elements",
+            list -> list.getElements(),
+            contains(expectedElements)));
+    }
+
+    private static <T, U> Matcher<T> hasFeature(
+        String name,
+        Function<? super T, U> extract,
+        Matcher<? super U> subMatcher) {
+        return new FeatureMatcher<T, U>(subMatcher, name, name) {
+            @Override
+            protected U featureValueOf(T actual) {
+                return extract.apply(actual);
+            }
+        };
+    }
+}
-- 
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