ADVANCED Dynamic For loop construction Macro

@Echo off
::: { Macro Definition
Setlocal DisabledelayedExpansion
    (set \n=^^^
%= This creates an escaped Line Feed - DO NOT ALTER =%
)
::: [ For Loop Constructor macro. ] For advanced programmers who need to use dynamic for loop options during code blocks.
::: - usage: %n.For%{For loop options}{variable set}{For Metavariable}{commands to execute}
::: - use delayed !and! variable to construct concatenated commands in the new for loop.
    Set n.For=For %%n in (1 2) Do If %%n==2 (%\n%
        Set FOR=%\n%
        For /F "tokens=1,2,3,4 Delims={}" %%1 in ("!mac.in!") Do (%\n%
            Set "FOR=For /F %%1 %%3 in ("!%%2!") Do (%%~4)"%\n%
        )%\n%
        Call :Exc.For%\n%
    )Else Set mac.in=
    Set "and.=&&"
    Set "and=!and.!"
::: } End macro definition.
    Setlocal EnableDelayedExpansion& rem // required to expand n.For constructor macro
::: - Usage examples:
    Set "example=is a string line"
    %n.For%{"tokens=* delims="}{example}{%%G}{Echo/%%~G}
    %n.For%{"tokens=1,2,3,4 delims= "}{example}{%%G}{"Echo/%%~J %%~G %%~H %%~I !and! Echo/%%~I %%~G %%~H %%~J"}
    Set "example2=Code block example"
    For %%a in (1 2 3) do (
        %n.For%{"Tokens=%%a Delims= "}{example2}{%%I}{"For /L %%# in (1 1 4) Do (Set %%I[%%#]=%%a%%#) !and! Set %%I[%%#]"}
    )
    Pause > Nul
    Goto :EOF
:Exc.For
    %FOR%
Exit /B