Digit separator char '_' like in new Delphi

https://docwiki.embarcadero.com/RADStudio/Alexandria/en/What%27s_New#Binary_Literals_and_Digit_Separator

tells us:

The language also introduces a digit separator that can be used to improve the readability of literal values with many digits. The separator is the underscore “_” and it is basically ignored when parsing and compiling the code. This is very similar to the feature introduced in C# 7.0.

const
  AMillion = 1_000_000;

Of course, you can use the digit separators for binary literals.

FPC 3.2.3 don't support it. Test file:

1_2
1_2.3_4e+5_6
1_2._3_4e+_5_6 //is it ok?
$A_B
$_A_B //is it ok?
%1_0
%_1_0 //is it ok?
&7_0
&_7_0 //is it ok?