[fpc-devel] Some new "in" operator functions

[Michael Van Canneyt]

On Tue, 5 Mar 2019, J. Gareth Moreton wrote:

> Hi everyone,
>
> I've developed a couple of "in" operator overrides so you can use " in "
> (useful in parsing tools, say, to see if a character belongs to a set of
> delimiters) and " in ". e.g.
>
> operator in(_Char: Char; _Set: array of Char): Boolean;
> var
>   C: Char;
> begin
>   Result := False;
>   for C in _Set do
>     if C = _Char then
>     begin
>       Result := True;
>       Exit;
>     end;
> end;
>
> Would these be welcome in one of the core units? And if so, which unit
> would you recommend?

At the risk of sounding stupid, but why would you want to add this if the
compiler supports this out of the box ?

var
  C : char;

begin
   if ParamCount>0 then
     c:=paramstr(1)[1]
   else
     c:=#0;
   if c in ['a','b','c'] then
     writeln('ok')
   else
     writeln('not ok')
end.

Michael.