Migrated source code from Simantics SVN

[simantics/platform.git] / bundles / org.simantics.scl.compiler / src / org / simantics / scl / compiler / constants / singletons / NothingConstant.java

diff --git a/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/constants/singletons/NothingConstant.java b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/constants/singletons/NothingConstant.java
new file mode 100644 (file)
index 0000000..6778af2
--- /dev/null
+++ b/bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/constants/singletons/NothingConstant.java
@@ -0,0 +1,50 @@
+package org.simantics.scl.compiler.constants.singletons;\r
+\r
+import org.objectweb.asm.Label;\r
+import org.simantics.scl.compiler.constants.Constant;\r
+import org.simantics.scl.compiler.internal.codegen.continuations.Cont;\r
+import org.simantics.scl.compiler.internal.codegen.references.IVal;\r
+import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;\r
+import org.simantics.scl.compiler.internal.codegen.utils.TransientClassBuilder;\r
+import org.simantics.scl.compiler.types.TVar;\r
+import org.simantics.scl.compiler.types.Types;\r
+import org.simantics.scl.compiler.types.kinds.Kinds;\r
+\r
+public class NothingConstant extends Constant {\r
+    \r
+    private static final TVar A = Types.var(Kinds.STAR);\r
+    public static final NothingConstant INSTANCE = new NothingConstant();\r
+    \r
+    private NothingConstant() {\r
+        super(Types.forAll(A, Types.apply(Types.MAYBE, A)));\r
+    }\r
+\r
+    @Override\r
+    public void push(MethodBuilder mb) {\r
+        mb.loadNull();\r
+    }\r
+    \r
+    @Override\r
+    public void deconstruct(MethodBuilder mb, IVal parameter,\r
+            Cont success, Label failure) {\r
+        if(failure != null) {    \r
+            parameter.push(mb);\r
+            mb.ifNullBranch(failure, false);\r
+        }\r
+        mb.jump(success);\r
+    }\r
+    \r
+    public int constructorTag() {\r
+        return 0;\r
+    }\r
+    \r
+    @Override\r
+    public String toString() {\r
+        return "Nothing";\r
+    }\r
+    \r
+    @Override\r
+    public Object realizeValue(TransientClassBuilder classBuilder) {                \r
+        return null;\r
+    }\r
+}\r