SS64 Forum

allal

Member

Registered: 10 Jan 2011

Posts: 48

how do you preserve "!" in var with delayedexpansion

please help
it seems i can't get this code to work correctly
to successfully expand a var containing "!" char with delayed expansion

echo first test&echo.
call :cmdstring /string "qwer!y" /replace "!" "t"
echo.&echo.&echo second test&echo.
call :cmdstring /string "qwer!y" /replace "w" "t"
echo.&pause
goto :eof

:cmdstring
setlocal enabledelayedexpansion
set replacecounter=0
set "str2rep="
set "repstr="

for %%R IN (%*) do (
   set "strparam=%%~R"
    IF "!stringcounter!"=="1"   set "string=%%~R"  &set /a stringcounter+=1 
   IF "!replacecounter!"=="2"  set "repstr=%%~R"  &set /a replacecounter+=1
    IF "!replacecounter!"=="1"  set "str2rep=%%~R" &set /a replacecounter+=1
    IF /I %%R==/replace         set /a replacecounter+=1
    IF /I "!strparam:~0,2!"=="/s"  set /a stringcounter+=1
)

set old_string=%string%
set old_string
set str2rep
set repstr
set "new_string="
for /f "tokens=* delims=" %%b in ('
  %comspec% /u /c echo:"%old_string%" ^|more ^|find /v """"') do (
    if "%%b"=="!str2rep!" (
        call set "new_string=%%new_string%%%%repstr%%"
    ) else (
        call set "new_string=%%new_string%%%%b"
    )
)

set new_string
goto :eof
pause

output:

first test

old_string=qwer
environnement variable str2rep is not defined.
environnement variable repstr is not defined.
new_string=qwer


second test

old_string=qwery
str2rep=w
repstr=t
new_string=qtery

in both test the exclamation mark will vanish
in the first test nothing will be replaced because the character to replace was an exclamation mark
and in the second test replacement is done but no exclamation mark is preserved

Last edited by allal (23 May 2011 18:32)

jeb

Member

From: Germany

Registered: 19 Nov 2010

Posts: 109

Re: how do you preserve "!" in var with delayedexpansion

You loose the "!" in the line

for %%R IN (%*) do (

You can access it only without delayed expansion.

@echo off
call :cmdstring result "abc!ef"
setlocal EnableDelayedExpansion
echo !result!
goto :eof

:cmdstring
set "string=%~2"
setlocal EnableDelayedExpansion
set "newString=!string:~-3!-!string:~0,3!
(
    endlocal
    set "%~1=%newString%"
    goto :eof
)

jeb

allal

Member

Registered: 10 Jan 2011

Posts: 48

Re: how do you preserve "!" in var with delayedexpansion

well done jeb

allal

Member

Registered: 10 Jan 2011

Posts: 48

Re: how do you preserve "!" in var with delayedexpansion

i think that is a mistake to make var expansion using ! or % or any character

sooner or later you will face a percent sign,exclamation,ampersand and the result is an error or a character vanishement.

actually a var don't need characters to be expanded, this method really make things complex

and it is not needed at all and it will be very great if this method was not implemented.

like any other language var expansion is just writing var without quotes

example:

REM declare and assign a value to a variable
SET var="st!r%in&g"

REM expand the variable
echo var

REM don't expand the variable
echo "var"
echo 'var'
echo ^var

output :

REM expand the variable
"st!r%in&g"

REM don't expand the variable
"var"
'var'
^var

they could use enabledelayedexpansion
then variable expansion will be delayed
using only the variable but without any extra useless character

believe it or not it will be very flexible and easy if this unwanted method doesn't exist

allal

Member

Registered: 10 Jan 2011

Posts: 48

Re: how do you preserve "!" in var with delayedexpansion

i think a character must instead be used to identify a variable
for you to know that is a variable
for a user to quickly spot a variable in huge line of code or huge text

not to be used for expansion

example :

!var=value
or
%var=125
or
like the most language
$var="string"