An expression function that would allow me to replace all ‘*’ with ‘%’.
where * is an arbitrary string and % is it’s replacement.
As a simple start, * and % could be a single char. Although support for the full perl s/// function would be ideal
Sounds good, shouldn’t be a problem. (In the meantime you could write one in Python and use the [tt]runScript[/tt] expression.)
Already done 
This is in for 7.1.3 - not regex but simply substring-based. replace(source, target, replacement)