When this extension is enabled (the default), the Irie Pascal compiler will allow non-numeric statement labels. In Standard (ISO/IEC 7185) Pascal statement labels must be numeric and between 0 and 9999. When this extension is enabled, you can declare and use labels containing letters and underscores.
For example in the following program, loop is used as a statement label.
program name(output);
label loop;
var
i : integer;
begin
i := 1;
loop:
writeln(i);
i := i + 1;
if i <= 20 then goto loop;
end.