Re: Optimising string handling in application

[tmoran@acm.org]

> However, sometimes I miss the expressionness of perl:
>
> s/([^;]*;ME001=)([^;]*)(;[^;]*)/$1$callsign$3/;

What does that do if "ME001=" or the ';' aren't present?

What does "expressionness" mean?  Does:

function Replace_Callsign_In_Message(M, C : String) return String is
  use Ada.Strings.Fixed;
  Eq : constant Positive := Index(M, "ME001=")+5;
begin
  return M(M'first .. Eq) & C & M(Index(M(Eq .. M'last),";') .. M'last);
end Replace_Callsign_In_Message;

have more or less of it than:

function Replace_Callsign_In_Message(Msg, New_Callsign : String) return String is
  use Ada.Strings.Fixed;
  Eq : constant Positive := Index(Msg, "ME001=")+5;
  Semi : Natural;
begin
  if Eq = 5 then raise Constraint_Error;end if; -- missing "ME001="
  Semi := Index(Msg, ";");
  if Semi = 0 then raise Constraint_Error;end if; -- missing ";"
  return Msg(Msg'first .. Eq)
         & New_Callsign
         & Msg(Semi .. Msg'last);
end Replace_Callsign_In_Message;