Nesting three (3) for loops & EnableDelayedExpansion - windows

Question

In trying to integrate a third for loop & it's supporting code into existing
code & I've reached the limits of my understanding. I'm totally lost on how to reference
the various variables in this complex "EnableDelayedExpansion" environment.
Additionally, should "EnableDelayedExpansion" / endlocal be turned on/off at each
For loop or just once at the start & end of the program.
:: ------------------ Beg For #1
For /L %%a in (%XBEG%,1,%XEND%) do (
cls
echo : %%a
set L=1
:: ------------------ Beg For #2
For /F "delims=" %%b in (%XDRV%%XPATH%%%a\1dir%%a.txt) do (
set XTITLE=%%b
echo Line !L!: !XTITLE!
If not {!XTITLE!}=={!XTITLE:%XDRV%%XPATH%%%a\!} set XTITLE=!XTITLE:~18,-4!
::
:: ------------------ Beg For #3 --- New code
:: Write title to the xtemp file. Place the redirection
:: symbol, i.e., greater than sign, IMMEDIATELY after vari
:: to avoid a trailing space, i.e., ( %vari%> )
echo !XTITLE!> %XDRV%%XPATH%xtemp.txt
:: Get the file size in bytes, each byte = one character
For %%c in (%XDRV%%XPATH%xtemp.txt) do set /a XLEN=%%~zc
:: Subtract 2 bytes, 1 for CR, 1 for LF, from Length
set /a XLEN -=2
cls
echo : ===[ Debug ]======================================
echo - !XTITLE! - has !XLEN! characters.
set /a XPAD=50-!XLEN!
echo - Xpad is !XPAD!
:: Build the Index entry
set XENTRY=%XPADs%%XTITLE%%XPAD%%%a
echo - %XENTRY%
pause
:: remove the xtemp file
del %XDRV%%XPATH%xtemp.txt
set /a L=!L!+1
pause
:: ------------------ end of New code
):: End For #2
)
:: End For #1
:: Clean Up For3
set XTITLE=
set L=
Goto DOS
The "EnableDelayedExpansion" / endlocal are currently placed at the start & end
of the program.
It's my hope that this situation is of sufficient interest to the community as
your help is desperately needed & would be VERY much appreciated.

Answer 1

You never state exactly what your problems are. You are doing some odd things with file paths, but I can't tell if what you are doing makes sense.
I do see some definite bugs:
1) If not {!XTITLE!}=={!XTITLE:%XDRV%%XPATH%%%a\!} ...
It looks like you are attempting search and replace to test if a variable contains a path string. But you forgot your =. Also, you should use quotes when doing search and replace or substring operations with delayed expansion within an IF test.
Corrected:
if not "!XTITLE!"=="!XTITLE:%XDRV%%XPATH%%%a\=!" ...
2) Additional delayed expansion needed in this existing code. Also, you have an extra unwanted s. I also like to use quotes to make sure there are no hidden spaces at the end of the assignment.
set XENTRY=%XPADs%%XTITLE%%XPAD%%%a
echo - %XENTRY%
Corrected:
set "XENTRY=!XPAD!!XTITLE!!XPAD!%%a"
echo - !XENTRY!
In general, I think your code could use more quotes during assignments.
There may be additional problems, but that is what I see without actually testing the code, and without knowing what it is supposed to do.
There are some optimizations possible
1) No need to delete the temp file each iteration. You only need to delete it at the end outside the outer loop.
2) You can eliminate the 2nd SET /A and subtract 2 within the 3rd loop.
For %%c in (%XDRV%%XPATH%xtemp.txt) do set /a XLEN=%%~zc - 2
3) No need to clear each variable at the end. Simply SETLOCAL at the beginning and ENDLOCAL at the end.
Regarding when to enable delayed expansion: Most likely you can simply enable delayed expansion at the beginning. But that will cause a problem if any of your title values include ! because the value will be corrupted when %%b is expanded if delayed expansion is enabled.
If a title may contain ! then you must toggle delayed expansion on and off within the 2nd loop. But then you have to preserve the value of L after the ENDLOCAL. You can do something like the following:
For /F "delims=" %%b in (%XDRV%%XPATH%%%a\1dir%%a.txt) do (
set XTITLE=%%b
setlocal enableDelayedExpansion
:: ... do your work with delayed expansion
:: Use a FOR loop to transport the value of L past ENDLOCAL
for %%N in (!L!) do (
endlocal
set "L=%%N"
)
):: End For #2