From 5b1f5568f25146b397bcdb7b570ddad74246969f Mon Sep 17 00:00:00 2001
From: =?utf8?q?Hannu=20Niemist=C3=B6?= <hannu.niemisto@semantum.fi>
Date: Wed, 16 Aug 2017 09:06:31 +0300
Subject: [PATCH] (refs #7433) Make Either type available in Java

Change-Id: I9ee7e4ca0bb2bf682b00447d8a44568276e74083
---
 .../META-INF/MANIFEST.MF                      |  1 +
 .../org.simantics.scl.runtime/scl/Prelude.scl |  9 +++++-
 .../simantics/scl/runtime/either/Either.java  |  4 +++
 .../simantics/scl/runtime/either/Left.java    | 29 +++++++++++++++++++
 .../simantics/scl/runtime/either/Right.java   | 29 +++++++++++++++++++
 5 files changed, 71 insertions(+), 1 deletion(-)
 create mode 100644 bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Either.java
 create mode 100644 bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Left.java
 create mode 100644 bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Right.java

diff --git a/bundles/org.simantics.scl.runtime/META-INF/MANIFEST.MF b/bundles/org.simantics.scl.runtime/META-INF/MANIFEST.MF
index aec2f1b85..382af3fc4 100644
--- a/bundles/org.simantics.scl.runtime/META-INF/MANIFEST.MF
+++ b/bundles/org.simantics.scl.runtime/META-INF/MANIFEST.MF
@@ -7,6 +7,7 @@ Bundle-RequiredExecutionEnvironment: JavaSE-1.8
 Export-Package: org.simantics.scl.runtime,
  org.simantics.scl.runtime.chr,
  org.simantics.scl.runtime.collection,
+ org.simantics.scl.runtime.either,
  org.simantics.scl.runtime.exceptions,
  org.simantics.scl.runtime.function,
  org.simantics.scl.runtime.io,
diff --git a/bundles/org.simantics.scl.runtime/scl/Prelude.scl b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
index eb1e8cd6f..818c50543 100644
--- a/bundles/org.simantics.scl.runtime/scl/Prelude.scl
+++ b/bundles/org.simantics.scl.runtime/scl/Prelude.scl
@@ -1273,7 +1273,14 @@ The Either type represents values with two possibilities: a value of type `Eithe
 The `Either` type is sometimes used to represent a value which is either correct or an error; by convention, the `Left` constructor
 is used to hold an error value and the `Right` constructor is used to hold a correct value (mnemonic: "right" also means "correct").
 """
-data Either a b = Left a | Right b
+@JavaType "org.simantics.scl.runtime.either.Either"
+data Either a b =
+    @JavaType "org.simantics.scl.runtime.either.Left"
+    @FieldNames [value]
+    Left a
+  | @JavaType "org.simantics.scl.runtime.either.Right"
+    @FieldNames [value]
+    Right b
 
 deriving instance (Ord a, Ord b) => Ord (Either a b)
 deriving instance (Show a, Show b) => Show (Either a b)
diff --git a/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Either.java b/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Either.java
new file mode 100644
index 000000000..c79290782
--- /dev/null
+++ b/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Either.java
@@ -0,0 +1,4 @@
+package org.simantics.scl.runtime.either;
+
+public interface Either {
+}
diff --git a/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Left.java b/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Left.java
new file mode 100644
index 000000000..1e0c29b1f
--- /dev/null
+++ b/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Left.java
@@ -0,0 +1,29 @@
+package org.simantics.scl.runtime.either;
+
+public class Left implements Either {
+    public final Object value;
+
+    public Left(Object value) {
+        this.value = value;
+    }
+    
+    @Override
+    public String toString() {
+        return "Left " + value;
+    }
+    
+    @Override
+    public boolean equals(Object obj) {
+        if(this == obj)
+            return true;
+        if(obj == null || obj.getClass() != getClass())
+            return false;
+        Right other = (Right)obj;
+        return value == null ? other.value == null : value.equals(other.value);
+    }
+    
+    @Override
+    public int hashCode() {
+        return 31 * (value == null ? 0 : value.hashCode()) + 13532;
+    }
+}
diff --git a/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Right.java b/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Right.java
new file mode 100644
index 000000000..27aeec914
--- /dev/null
+++ b/bundles/org.simantics.scl.runtime/src/org/simantics/scl/runtime/either/Right.java
@@ -0,0 +1,29 @@
+package org.simantics.scl.runtime.either;
+
+public class Right implements Either {
+    public final Object value;
+
+    public Right(Object value) {
+        this.value = value;
+    }
+    
+    @Override
+    public String toString() {
+        return "Right " + value;
+    }
+    
+    @Override
+    public boolean equals(Object obj) {
+        if(this == obj)
+            return true;
+        if(obj == null || obj.getClass() != getClass())
+            return false;
+        Right other = (Right)obj;
+        return value == null ? other.value == null : value.equals(other.value);
+    }
+    
+    @Override
+    public int hashCode() {
+        return 31 * (value == null ? 0 : value.hashCode()) + 13533;
+    }
+}
-- 
2.47.1