[Batch] My Expand Routine

Expand.bat

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:: This works by exploiting the set and defined commands.  If the Var is null,
:: then the set command will fail, the error message is caught, and the defined
:: command will fail because there should NEVER exist a variable named =.
:: Usage: call :Expand A %~1 0
:: The default works by exploiting how commands are parsed.  If parameter 1 is
:: empty, then 0 will be passed to the routine as Value.
:: Author: David Ruhmann
:Expand <Var> [Value] [Default]
2>nul set "%~1=%~2"
if defined %~1 = exit /b 0
exit /b 1