you can just create some basic script to do this whenever you need this. The script would be slower than if it was implimented internally, but I have to agree with madewokherd that it would definately hinder over all performance and all for a very specific circumstance.
Here's an example script for you:
alias wee {
echo -a And here we go.. (10 is the limit as set in the alias sdi, and 1 is the default number)
set2 wee 1
echo -a Set it as: %wee
inc2 wee 6
echo -a Added 6: %wee
dec2 wee 3
echo -a Subtracted 3: %wee
inc2 wee 50
echo -a Incremented it 40 past it's limit: %wee
unset %wee
echo All done!
}
alias set2 {
set % $+ [ $1- ]
sdi $1
}
alias inc2 {
inc % $+ [ $1- ]
sdi $1
}
alias dec2 {
dec % $+ [ $1- ]
sdi $1
}
alias -l sdi { if ( [ % $+ [ $1 ] ] >= 10) { set % $+ [ $1 ] 1 } }
If you have the number decreasing every second or incrementing every second or something, then I suggest to you to create a more complex script that will have a timer running evert second, which will run an alias which will look through a list of variable names which would be stored in a hash file to check all the variables every second, removing variables that stop decreasing or incrementing, untill the hash file is empty, then the timer would be unset.
I think Narusegawa_Naru's suggestion is a much better suggestion, but still not a very important one.