Back to Questions
1.2k
views2
comments
Interface generator: extending generic interfaces and parameter names
websharper

I've been having a couple of issues making use of the WebSharper Interface Generator and was hoping that somebody might be able to point out where I'm going wrong.

The first issue is simply the use of parameter names. If I create a new 'Extension' type project in Visual Studio and add a parameter name to any of the terms using the '?name' format, it fails to compile. Is this a known issue or am I doing something drastically wrong?

The second issue relates to extending generic interfaces. Suppose I have an interface I1 as follows:

1
2
3
4
5
6
7
8
9

let I1 = Type.New ()
let I1Interface =
    Generic / fun t1 ->
        Interface "I1"
        |=> I1
        |+> [
            Generic - fun t2 ->
                "foo" => t1 ^-> t2
            ]

Now I want to create a second interface, I2, which extends the first interface. I have tried the following:

1
2
3
4
5
6
7
8
9
10

let I2 = Type.New ()
let I2Interface =
    Generic / fun t1 ->
        Interface "I2"
        |=> Extends [ I1.[t1] ]
        |=> I2
        |+> [
            Generic - fun t2 ->
                "bar" => t2 ^-> t1
        ]

However, this fails to compile, telling me that I need to add a type annotation somewhere to make it work. If I replace Extends [ I1.[t1] ] with Extends [ I1 ] then it does compile, but gives me an error about insufficient types in scope when I try to use the binding. Any help gratefully appreciated!

.

FYI, the bit about the ? operator in the extension template has been added as issue #303 in the tracker.

By on 11/28/2014 11:42 AM ()

  • For the ? naming, the issue is that WIG's definition of ? is overridden by (?) : obj -> string -> 'a, which is defined in IntelliFactory.WebSharper to access object fields in client-side objects (a?x compiles to a.x in JavaScript). The solution is to remove open IntelliFactory.WebSharper from your WIG file.

    This is actually something that we need to fix in the WIG project template: the namespace IntelliFactory.WebSharper should not be opened.

    Edit: I added an issue to the tracker for the WIG extension project template.

  • For the interfaces issue, what happens is that Generic / fun ... itself returns a function, that you can apply as follows:

1
2
3
4
5

let I2Interface =
	Generic / fun t1 ->
    	Interface "I2"
        |=> Extends [ I1 t1 ]
        // ...
By on 11/28/2014 11:34 AM ()

    Topic tags

    IntelliFactory Offices Copyright (c) 2011-2012 IntelliFactory. All rights reserved.
    Home | Products | Consulting | Trainings | Blogs | Jobs | Contact Us | Terms of Use | Privacy Policy | Cookie Policy     		Built with WebSharper