Function embedded in a function?

[Ian Branch 121]

Hi Team,

I think, from time to time I have seen a function embedded in another function.  I think.

Something like..

function foobar(param1, param2: string): string;

var

somevar: string;

begin

  function inside(Param3: string): string;

  var  anothervar: string;

  Begin  

    Do something with Param3;

    ....

    ...

    Result := anothervar;

  end;

...

Somevar := inside(somestring);

Result := Somevar;

end;

Is this doable?  If so, what is the mechanism for it pls?

Why do I want to do this?  So I can embed a function in the main function and not have to have it as a separate app function.

 

Regards & TIA,

Ian

 

 

[Remy Lebeau 1255]

Yes, it is doable, but the syntax is slightly different than you showed. The inner function has to be defined before the 'begin' of the outer function, eg:

function foobar(param1, param2: string): string;
var
  somevar: string;

  function inside(Param3: string): string;
  var
    anothervar: string;
  Begin
    Do something with Param3;
    ...
    Result := anothervar;
  end;

begin
  Somevar := inside(somestring);
  Result := Somevar;
end;

This is covered in Embarcadero's documentation: Nested Routines

Edited March 31, 2019 by Remy Lebeau

[Ian Branch 121]

Ahh.  Excellent.  Thanks Remy.