[Pas2js] @pointer/reference inside ASM block - missing feature

[warleyalex]

I came across an issue when using the ASM block/section: "you have to
initialize the variables reference" before you use that reference iniside
the ASM block.
for instance:
---------------------
var
  s: string;
Begin
  s = 'Hello World!';
  ASM
    console.log(s);
  End;
---------------------
transpiles to:
---------------------
  var $mod = this;
  this.s = '';
  $mod.$main = function(){
    $mod.s = "Hello World!";
    console.log(s);
  };
---------------------

Pas2JS does not support @ prefix with the ASM Block:
----------------------------------------------------
Since the pas2js compiler does neither parse, nor check the syntax of the
JS, it does not understand the prefix@ inside the ASM section, for instance:
-------------
function getSomeData: JSValue;
 begin
   asm
     /* return a data structure */
     @Result = {first:"hello",second:"hello2"}
   end;
 end;
------------
You'll get "unexpected token ILLEGAL".

The @ prefix can be used inside the ASM block, as such, the compiler needs
to be able to quickly figure out if you are using a JS based variable or an
Object Pascal variable. So all Object Pascal variables have to be prefixed
with the @ character. 

and JSValue serves as a universal data reference. JSValue are special
however, the JSValue type can just used to transport data from one method to
another.

I think the @ pointer could be used at all the standard types are there:
string, boolean, float, integer and so on. You also have records, interfaces
and enumerations to play with. It really is a neat system once you get the
hang of it.

When you use the @ prefix inside the ASM block, the pas2js should initialize
variables types/functions beforehand.

Example: this code compile but does not work. (see no @ prefix in ASM)
---------------------------------------------------------------------
  procedure ProcessMessage;
      function doTask(aResponse: JSValue): JSValue;
      begin
        console.log( aResponse );
      end;

      function _doTask0(aResponse: JSValue): JSValue;
      begin
        result := wait(1000);
      end;

      function _doTask1(aResponse: JSValue): JSValue;
      begin
        console.log('hi, after 10 secs');
        result := wait(500);
      end;

      function _doTask2(aResponse: JSValue): JSValue;
      begin
        console.log('hi after 5 more secs');
        result := wait(200);
      end;

      function _doTask3(aResponse: JSValue): JSValue;
      begin
        console.log('hi after 2 more secs');
        result := wait(0);
      end;

     begin

       ASM
         Promise.resolve()
           .then(doTask.bind(null, 'teste'))
           .then(_doTask0)
           .then(_doTask1)
           .then(_doTask2)
           .then(_doTask3);
       END;

    end;
---------------------------------------------------------------------
the pas2js will emit:
-------------------
      function ProcessMessage() {
        Promise.resolve()
        .then(doTask.bind(null, 'teste'))
        .then(_doTask0)
        .then(_doTask1)
        .then(_doTask2)
        .then(_doTask3);
      };
--------------------------------------
See, the compiler will not emit some methods, smart linking has omitted some
wanted methods: doTask0, _doTask0, _doTask1, _doTask2, _doTask3.

An workaround would be to create a dummy variable to point to the methods;
  var
    res: TJPromiseCallback_fn;
       {...}
       { dummy variable will allow to smart linking emit the required
methods }
       res:= @doTask;
       res:= @_doTask0;
       res:= @_doTask1;
       res:= @_doTask2;
       res:= @_doTask3;
--------------------------

We could use the @prefix here, pas2js could auto initialize the
variable/functions reference. e.g.

ASM
 Promise.resolve()
  .then((@doTask).bind(null,'teste'))
  .then(@_doTask0)
  .then(@_doTask1)
  .then(@_doTask2)
  .then(@_doTask3);
END;





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