How to use a value instead of a string in regular expression?

[mrz2003]

For example, if $aaa=="1.1", then by using
"$aaa =~ s/(\d+)$/($1)+1/;"
I want to change $aaa to "1.2".
Of couse, the regular expression is not correct.
Thanks!

 

[Gunnar Hjalmarsson]

For example, if $aaa=="1.1", then by using
"$aaa =~ s/(\d+)$/($1)+1/;"
I want to change $aaa to "1.2".

Add the /e modifier.