How to make an alias of a function/procedure?

Question

In Delphi is there a way to declare a procedure as an alias of another? Something like:

function AnAliasToUpperCase(const S: AnsiString): AnsiString = system.AnsiStrings.UpperCase;  

and later in the program calling AnAliasToUpperCase or UpperCase must be exactly the same.

Answer 1

Defining it e.g. like a constant declaration:

const
  AliasToUpperCase: function(const S: AnsiString): AnsiString = System.AnsiStrings.UpperCase;

might work for your needs.

Answer 2

The proper answer to the question "How to make an alias to a function/procedure" is "You can't".

But there are two workarounds to simulate this which both might introduce a bit of overhead - the first is the const as shown in the other answer.

Additionally to declaring it as const you can also declare it as new inline routine:

function AliasToUpperCase(const S: AnsiString): AnsiString; inline;
begin
  Result := System.AnsiStrings.UpperCase(S);
end;

But then you are depending on the compiler settings for inlining and need to also add the AnsiStrings unit to wherever you are calling AliasToUpperCase or you will get the H2443 Inline function has not been expanded because unit is not specified in USES list warning.

For this function signature it works but for other return types you might suffer from missing return value optimization and have extra value copies.