subtype Questions
4
I've recently found myself in a situation where I wanted to check if a Type is a subtype of another Type this is what I've tried
abstract class Record{}
class TimeRecord extends Record{}
void ...
1
I'm getting a runtime error from a Dart generic function:
Widget card = widget.cardBuilder(item);
Which generates:
type '(Contact) => Widget' is not a subtype of type '(DeletableItem) =>...
0
How do I test for subtypes in both Python 2 and Python 3?
In Python 2.7.18:
>>> import typing
>>> type_ = typing.List[str]
>>> issubclass(type_, typing.List)
True
But in...
Portulaca asked 23/1, 2022 at 18:36
6
Anyone see this before? I have a large Visual Studio project that keeps adding [Subtype]Designer[/Subtype] to my .vcproj then removing it on the next open and close of the project. There is only on...
Muhammadan asked 15/10, 2009 at 15:47
2
Solved
I have a type hierarchy constructed with perl6's subset command and some multi subs specialized on these type. How to give the highest precedence to the sub specialized by the most narrow subtype w...
Hegira asked 23/1, 2019 at 10:24
1
We often use type class dependence to emulate the sub typing relationship.
e.g:
when we want to express the sub typing relationship between Animal, Reptile and Aves in OOP:
abstract class Animal...
4
Solved
Here's the generic class I'm working with:
public interface IRepository<T> where T : EntityObject
{
RepositoryInstructionResult Add(T item);
RepositoryInstructionResult Update(T item);
R...
Sofar asked 14/6, 2012 at 13:35
2
Solved
A friend of mine posed a seemingly innocuous Scala language question last week that I didn't have a good answer to: whether there's an easy way to declare a collection of things belonging to some c...
Rumormonger asked 16/3, 2012 at 6:13
0
In the Argonaut DecodeJson trait there is a method ||| for chaining together decoders, so that the first succeeding decoder is chosen. There is also a similar method in DecodeResult which has the s...
3
Solved
I am learning the Relational Model and data modeling.
And I have some confusion in my mind regarding sub types.
I know that data modeling is an iterative process and there are many different ways ...
Caporetto asked 1/6, 2015 at 8:17
4
Solved
Here is what I know:
Double is a subtype of Number and List<Double> is not a subtype of List<Number>.
List<Dog> is not a subtype of List<Animal> because you can add Cat to...
1
Solved
I have a class called Product and some subclasses extending it. Now in my annotations I have many types, like this:
@JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.WRAPPER_OBJECT)
...
5
Solved
I am working on a program in which you can register complaints. There are three types of complaints: internal (errors from employees), external (errors from another company) and supplier (errors ma...
Emanuelemanuela asked 8/10, 2010 at 20:26
1
Solved
I want to compose several "traits" across several modules. A function might require multiple such "traits" as its input, i.e.:
type 'a x_t = < get_x : int ; .. > as 'a constraint 'a = < g...
2
Solved
Can anyone explain the subtype(<:) in the following code? Why it could be used like that? When we use that? Thanks.
trait SwingApi {
type ValueChanged <: Event
val ValueChanged: {
def u...
Bichromate asked 11/12, 2013 at 0:56
6
Solved
A subtype is established when a class is linked by means of extending or implementing. Subtypes are also used for generics.
How can I differentiate subtyping from subclasses?
1
Solved
I'd like to know about Isabelle/HOL subtypes. I explain a little about why it's important to me in my partial answer to my last SO question:
Trying to Treat Type Classes and Sub-types Like Sets an...
Orrery asked 26/4, 2013 at 7:35
2
Solved
Assume, we have:
class B
class A extends B
trait T
Then it holds:
val a: A with T = new A with T
a.isInstanceOf[B] // result is true !
Is it right to say, the isInstanceOf method checks, if ...
2
Solved
I am trying to parameterize some methods with very general type parameters.
As an example, in the REPL I first define:
trait Term
case class FunctionalTerm[+T <: Term](t: T) extends Term
Int...
Doubleacting asked 16/5, 2012 at 17:48
3
Solved
In the example below I have written one to_str() function and one set() procedure for every pls_integer subtype. The functions and procedures are almost identical except the type.
How I can elimin...
Exhilarant asked 15/7, 2011 at 9:37
5
Solved
I hear a lot about subtyping tables when designing a database, and I'm fully aware of the theory behind them. However, I have never actually seen table subtyping in action. How can you create subty...
Altheta asked 15/4, 2009 at 0:38
1
Solved
I'm interested to know the complete set of alternatives to subtype polymorphism in scala.
Polyphone asked 29/8, 2010 at 19:52
1
Solved
Using Visual Studio's Managed Package Framework, how can I inherit from C# so I can have C# property pages and C# project items? I've tried making a flavored project, but it was limited in terms of...
Edouard asked 21/6, 2009 at 18:16
2
In Scala, the PartialFunction[A, B] class is derived from type Function[A, B] (see Scala Reference, 12.3.3). However, this seems counterintuitive to me, since a Function (which needs to be defined ...
Iulus asked 30/5, 2009 at 21:51
1
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