How to use delayedexpansion to handle value in batch script - batch-file

Question

I am facing issue with reading contents of CSV files in batch script. I have a series of files say My_A_File.csv, My_B_File.csv ... My_Z_File.csv. The issue I was facing is reading special characters in them. Hence, wanted to read the values with delayedexpansion turned off.
When I read the values in the block with disabledelayedexpansion, they are empty! How can I handle this?
Script:
#echo off
setlocal enabledelayedexpansion
for /L %%g in (65,1,90) do (
cmd /c exit /b %%g
set codeval=!=ExitCodeAscii!
set fileToReadFrom=My_!codeval!_File.csv
if exist My_!codeval!_File.csv (
echo Outer-!fileToReadFrom!
echo Outer-!codeval!
setlocal disabledelayedexpansion
echo Inner-%fileToReadFrom%
echo Inner-%codeval%
endlocal
)
)
Output:
Outer-My_A_File.csv
Outer-A
Inner-
Inner-

Answer 1

This how the delayed expansion is supposed to work.However you can access the variables with CALL but this will the performance (mind that you cant CALL FOR ):
#echo off
setlocal enabledelayedexpansion
for /L %%g in (65,1,90) do (
cmd /c exit /b %%g
set codeval=!=ExitCodeAscii!
set fileToReadFrom=My_!codeval!_File.csv
if exist My_!codeval!_File.csv (
echo Outer-!fileToReadFrom!
echo Outer-!codeval!
setlocal disabledelayedexpansion
call echo Inner-%%fileToReadFrom%%
call echo Inner-%%codeval%%
endlocal
)
)
or you can use pipes.Which also will hit the performance (now you can use
break|for "usebackq" %%a in ("Inner-%%fileToReadFrom%%") do #echo %%~a):
#echo off
setlocal enabledelayedexpansion
for /L %%g in (65,1,90) do (
cmd /c exit /b %%g
set codeval=!=ExitCodeAscii!
set fileToReadFrom=My_!codeval!_File.csv
if exist My_!codeval!_File.csv (
echo Outer-!fileToReadFrom!
echo Outer-!codeval!
setlocal disabledelayedexpansion
break|echo Inner-%%fileToReadFrom%%
break|echo Inner-%%codeval%%
endlocal
)
)

Answer 2

Use a subroutine to process code with delayed expansion disabled as follows:
#echo off
rem skip subroutine code
goto :toMain
:toProcessDDE
rem subroutine to process delayed expansion disabled
setlocal disabledelayedexpansion
echo Inner-%fileToReadFrom%
echo Inner-%codeval%
endlocal
exit /B
:toMain
setlocal enabledelayedexpansion
for /L %%g in (65,1,90) do (
cmd /c exit /b %%g
set codeval=!=ExitCodeAscii!
set fileToReadFrom=My_!codeval!_File.csv
if exist My_!codeval!_File.csv (
echo Outer-!fileToReadFrom!
echo Outer-!codeval!
call :toProcessDDE
)
)
Read
CALL: Call one batch program from another, or call a subroutine and
EXIT: … quit the current subroutine …