[fpc-pascal] Next language feature for pas2js...

[Michael Van Canneyt]

On Tue, 1 May 2018, Ryan Joseph wrote:

>
>
>> On May 1, 2018, at 11:27 AM, Michalis Kamburelis <michalis.kambi at gmail.com> wrote:
>> 
>> I suspect that we will have a unit like WebGL in pas2js that exposes
>> the necessary JS functions for Pascal applications.
>
> Sure but how does the porting process look? I’m reading the wiki and it looks like it wraps JavaScript classes by doing stuff like:
>
> TJSFunction = class external name 'Function'(TJSObject)
>
> where “Function” is the JavaScript class name.

This is actually a less good example, it's a little tricky.

>
> Looking at https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API I see WebGLRenderingContext has the entire OpenGL API (I think). Does that mean we just do something like:
>
> const
>  GLfloat = MAP_TO_SOMETHING; // do we have external consts?

Of sorts.
   MyClass = Class external name 'my'
   const
     MyConst : integer
   end;

Will emit MyClass.MyConst. The compiler needs to know the type.

>
> type
>  TWebGLRenderingContext = class external name 'WebGLRenderingContext' (TJSObject)
>    procedure clearColor (red, green, blue, alpha: GLfloat); external name 'clearColor';
>  end;
>
> var
>  context :
> begin
>  context := GetCurrentContext; // document.getElementById(‘canvas’).getContext()
>  context.clearColor(0, 0, 0, 0);

That seems about correct. 
You don't need the "external name 'n'" if the name is typed correctly.

Michael.