TypeName cataMapperTypeName(DataConstructor dc) {
TypeName[] argsTypeNames =
concat(
dc.arguments().stream().map(DataArgument::type),
dc.typeRestrictions()
.stream()
.map(TypeRestriction::idFunction)
.map(DataArgument::type))
.map(t -> Utils.asBoxedType.visit(t, utils.types()))
.map(this::substituteTypeWithRecursionVar)
.map(TypeName::get)
.toArray(TypeName[]::new);
return adt.dataConstruction().isVisitorDispatch()
? argsTypeNames.length == 0
? ParameterizedTypeName.get(
ClassName.get(FlavourImpl.findF0(context.flavour(), utils.elements())),
TypeName.get(adt.matchMethod().returnTypeVariable()))
: argsTypeNames.length == 1
? ParameterizedTypeName.get(
ClassName.get(FlavourImpl.findF(context.flavour(), utils.elements())),
argsTypeNames[0],
TypeName.get(adt.matchMethod().returnTypeVariable()))
: ParameterizedTypeName.get(
Utils.getClassName(context, MapperDerivator.mapperInterfaceName(dc)),
concat(
concat(
dc.typeVariables().stream().map(TypeVariableName::get),
fold(
MapperDerivator.findInductiveArgument(utils, adt, dc),
Stream.<TypeName>of(),
tm ->
Stream.of(
ParameterizedTypeName.get(
ClassName.get(
FlavourImpl.findF0(
context.flavour(), utils.elements())),
TypeName.get(
adt.matchMethod().returnTypeVariable()))))),
Stream.of(TypeVariableName.get(adt.matchMethod().returnTypeVariable())))
.toArray(TypeName[]::new))
: TypeName.get(
utils
.types()
.getDeclaredType(
Utils.asTypeElement.visit(dc.deconstructor().visitorType().asElement()).get(),
dc.deconstructor()
.visitorType()
.getTypeArguments()
.stream()
.map(this::substituteTypeWithRecursionVar)
.toArray(TypeMirror[]::new)));
}
TypeMirror substituteTypeWithRecursionVar(TypeMirror tm) {
return utils.types().isSameType(tm, adt.typeConstructor().declaredType())
? utils
.types()
.getDeclaredType(
FlavourImpl.findF0(context.flavour(), utils.elements()),
adt.matchMethod().returnTypeVariable())
: tm;
}
private DeriveResult<DerivedCodeSpec> functionDispatchImpl(List<DataConstructor> constructors) {
NameAllocator nameAllocator = nameAllocator(constructors);
TypeElement f = FlavourImpl.findF(context.flavour(), utils.elements());
TypeName returnType =
TypeName.get(
utils
.types()
.getDeclaredType(
f,
adt.typeConstructor().declaredType(),
adt.matchMethod().returnTypeVariable()));
TypeSpec wrapper =
TypeSpec.anonymousClassBuilder("")
.addField(
FieldSpec.builder(returnType, nameAllocator.get("cata"))
.initializer(
CodeBlock.builder()
.addStatement(
"$L -> $L.$L($L)",
nameAllocator.get("adt var"),
nameAllocator.get("adt var"),
adt.matchMethod().element().getSimpleName(),
Utils.joinStringsAsArguments(
constructors
.stream()
.map(
constructor ->
constructor
.arguments()
.stream()
.map(DataArguments::getType)
.noneMatch(
tm ->
utils
.types()
.isSameType(
tm,
adt.typeConstructor()
.declaredType()))
? constructor.name()
: CodeBlock.builder()
.add(
"($L) -> $L.$L($L)",
Utils.asLambdaParametersString(
constructor.arguments(),
constructor.typeRestrictions()),
constructor.name(),
MapperDerivator.mapperApplyMethod(
utils, context, constructor),
Utils.joinStringsAsArguments(
Stream.concat(
constructor
.arguments()
.stream()
.map(
argument ->
utils
.types()
.isSameType(
argument
.type(),
adt.typeConstructor()
.declaredType())
? "() -> this."
+ nameAllocator
.get(
"cata")
+ "."
+ FlavourImpl
.functionApplyMethod(
utils,
context)
+ "("
+ argument
.fieldName()
+ ")"
: argument
.fieldName()),
constructor
.typeRestrictions()
.stream()
.map(
TypeRestriction
::idFunction)
.map(
DataArgument
::fieldName))))
.build()
.toString())))
.build())
.build())
.build();
MethodSpec cataMethod =
MethodSpec.methodBuilder("cata")
.addModifiers(Modifier.PUBLIC, Modifier.STATIC)
.addTypeVariables(
Stream.concat(
adt.typeConstructor().typeVariables().stream(),
Stream.of(adt.matchMethod().returnTypeVariable()))
.map(TypeVariableName::get)
.collect(Collectors.toList()))
.returns(returnType)
.addParameters(
constructors
.stream()
.map(
dc ->
ParameterSpec.builder(
cataMapperTypeName(dc), MapperDerivator.mapperFieldName(dc))
.build())
.collect(toList()))
.addStatement("return $L.$L", wrapper, nameAllocator.get("cata"))
.build();
return result(methodSpec(cataMethod));
}
public static DeriveResult<DerivedCodeSpec> derive(
AlgebraicDataType adt, DeriveContext deriveContext, DeriveUtils deriveUtils) {
// skip constructors for enums
if (adt.typeConstructor().declaredType().asElement().getKind() == ElementKind.ENUM) {
return result(none());
}
TypeConstructor typeConstructor = adt.typeConstructor();
TypeElement lazyTypeElement =
FlavourImpl.findF0(deriveContext.flavour(), deriveUtils.elements());
TypeName lazyArgTypeName =
TypeName.get(
deriveUtils.types().getDeclaredType(lazyTypeElement, typeConstructor.declaredType()));
String lazyArgName = Utils.uncapitalize(typeConstructor.typeElement().getSimpleName());
TypeName typeName = TypeName.get(typeConstructor.declaredType());
List<TypeVariableName> typeVariableNames =
adt.typeConstructor()
.typeVariables()
.stream()
.map(TypeVariableName::get)
.collect(Collectors.toList());
String className = "Lazy";
TypeSpec.Builder typeSpecBuilder =
TypeSpec.classBuilder(className)
.addModifiers(Modifier.PRIVATE, Modifier.STATIC, Modifier.FINAL)
.addTypeVariables(typeVariableNames)
.addField(
FieldSpec.builder(
TypeName.get(Object.class), "lock", Modifier.PRIVATE, Modifier.FINAL)
.initializer("new Object()")
.build())
.addField(FieldSpec.builder(lazyArgTypeName, "expression", Modifier.PRIVATE).build())
.addField(
FieldSpec.builder(typeName, "evaluation", Modifier.PRIVATE, Modifier.VOLATILE)
.build())
.addMethod(
MethodSpec.constructorBuilder()
.addParameter(ParameterSpec.builder(lazyArgTypeName, lazyArgName).build())
.addStatement("this.expression = $N", lazyArgName)
.build())
.addMethod(
MethodSpec.methodBuilder("eval")
.addModifiers(Modifier.PRIVATE)
.returns(typeName)
.addCode(
CodeBlock.builder()
.addStatement("$T _evaluation = this.evaluation", typeName)
.beginControlFlow("if (_evaluation == null)")
.beginControlFlow("synchronized (this.lock)")
.addStatement("_evaluation = this.evaluation")
.beginControlFlow("if (_evaluation == null)")
.addStatement(
"this.evaluation = _evaluation = expression.$L()",
Utils.getAbstractMethods(lazyTypeElement.getEnclosedElements())
.get(0)
.getSimpleName())
.addStatement("this.expression = null")
.endControlFlow()
.endControlFlow()
.endControlFlow()
.addStatement("return _evaluation")
.build())
.build())
.addMethod(
Utils.overrideMethodBuilder(adt.matchMethod().element())
.addStatement(
"return this.eval().$L($L)",
adt.matchMethod().element().getSimpleName(),
Utils.asArgumentsStringOld(adt.matchMethod().element().getParameters()))
.build());
if (adt.typeConstructor().declaredType().asElement().getKind() == ElementKind.INTERFACE) {
typeSpecBuilder.addSuperinterface(typeName);
} else {
typeSpecBuilder.superclass(typeName);
}
typeSpecBuilder.addMethods(
optionalAsStream(
findAbstractEquals(typeConstructor.typeElement(), deriveUtils.elements())
.map(
equals ->
deriveUtils
.overrideMethodBuilder(equals)
.addStatement(
"return this.eval().equals($L)",
equals.getParameters().get(0).getSimpleName())
.build()))
.collect(Collectors.toList()));
typeSpecBuilder.addMethods(
optionalAsStream(
findAbstractHashCode(typeConstructor.typeElement(), deriveUtils.elements())
.map(
hashCode ->
deriveUtils
.overrideMethodBuilder(hashCode)
.addStatement("return this.eval().hashCode()")
.build()))
.collect(Collectors.toList()));
typeSpecBuilder.addMethods(
optionalAsStream(
findAbstractToString(typeConstructor.typeElement(), deriveUtils.elements())
.map(
toString ->
deriveUtils
.overrideMethodBuilder(toString)
.addStatement("return this.eval().toString()")
.build()))
.collect(Collectors.toList()));
return result(
codeSpec(
typeSpecBuilder.build(),
MethodSpec.methodBuilder("lazy")
.addModifiers(Modifier.PUBLIC, Modifier.STATIC)
.addTypeVariables(
typeConstructor
.typeVariables()
.stream()
.map(TypeVariableName::get)
.collect(Collectors.toList()))
.addParameter(lazyArgTypeName, lazyArgName)
.returns(typeName)
.addStatement(
"return new $L$L($L)",
className,
typeVariableNames.isEmpty() ? "" : "<>",
lazyArgName)
.build()));
}