constants/singletons/JustConstant.java

   1 package org.simantics.scl.compiler.constants.singletons;
   2
   3 import org.cojen.classfile.TypeDesc;
   4 import org.objectweb.asm.Label;
   5 import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
   6 import org.simantics.scl.compiler.constants.FunctionValue;
   7 import org.simantics.scl.compiler.constants.GetPrimitiveConstant;
   8 import org.simantics.scl.compiler.constants.LocalVariableConstant;
   9 import org.simantics.scl.compiler.constants.NoRepConstant;
  10 import org.simantics.scl.compiler.internal.codegen.continuations.Cont;
  11 import org.simantics.scl.compiler.internal.codegen.references.IVal;
  12 import org.simantics.scl.compiler.internal.codegen.references.Val;
  13 import org.simantics.scl.compiler.internal.codegen.types.JavaTypeTranslator;
  14 import org.simantics.scl.compiler.internal.codegen.utils.LocalVariable;
  15 import org.simantics.scl.compiler.internal.codegen.utils.MethodBuilder;
  16 import org.simantics.scl.compiler.types.TVar;
  17 import org.simantics.scl.compiler.types.Type;
  18 import org.simantics.scl.compiler.types.Types;
  19 import org.simantics.scl.compiler.types.exceptions.MatchException;
  20 import org.simantics.scl.compiler.types.kinds.Kinds;
  21
  22 public class JustConstant extends FunctionValue {
  23
  24     private static final TVar A = Types.var(Kinds.STAR);
  25     public static final JustConstant INSTANCE = new JustConstant();
  26
  27     private JustConstant() {
  28         super(new TVar[] {A}, Types.NO_EFFECTS, Types.apply(Types.MAYBE, A), A);
  29     }
  30
  31     @Override
  32     public Type applyExact(MethodBuilder mb, Val[] parameters) {
  33         parameters[0].push(mb);
  34         mb.box(parameters[0].getType());
  35         return getReturnType();
  36     }
  37
  38     @Override
  39     public void deconstruct(MethodBuilder mb, IVal parameter,
  40             Cont success, Label failure) {
  41         Type componentType;
  42         try {
  43             componentType = Types.matchApply(Types.MAYBE, parameter.getType());
  44         } catch (MatchException e) {
  45             throw new InternalCompilerError();
  46         }
  47         TypeDesc componentTypeDesc =
  48                 mb.getJavaTypeTranslator().toTypeDesc(componentType);
  49
  50         if(failure == null) {
  51             IVal val = componentTypeDesc.isPrimitive()
  52                     ? new GetPrimitiveConstant(componentType, parameter, componentTypeDesc)
  53                     : parameter;
  54             mb.jump(success, val);
  55         }
  56         else {
  57             Label failureLabel = mb.createLabel();
  58
  59             parameter.push(mb);
  60             mb.dup();
  61             mb.ifNullBranch(failureLabel, true);
  62
  63             if(componentTypeDesc.equals(TypeDesc.VOID)) {
  64                 mb.pop();
  65                 mb.jump(success, new NoRepConstant(componentType));
  66             }
  67             else {
  68                 if(componentTypeDesc.isPrimitive())
  69                     mb.convert(JavaTypeTranslator.toObjectType(componentTypeDesc), componentTypeDesc);
  70
  71                 LocalVariable lv = mb.createLocalVariable("temp", componentTypeDesc);
  72                 mb.storeLocal(lv);
  73
  74                 mb.jump(success, new LocalVariableConstant(componentType, lv));
  75             }
  76
  77             //
  78             mb.setLocation(failureLabel);
  79             mb.pop();
  80             mb.branch(failure);
  81         }
  82     }
  83     public int constructorTag() {
  84         return 1;
  85     }
  86     @Override
  87     public String toString() {
  88         return "Just";
  89     }
  90 }