yes, I use them also in my 4gl legacy app. programming language, which is called Powerhouse. Although I don't know that it's called a regular expression in that language, but typical code might look something like...
sele if matchpattern(gain_loss_code[1:2],"GA|AC|IA") -- so, very similar.
but "gain_loss_code" is just a data element; you don't have to do anything to it first in order to check it, (or, in the above example, I'm checking the 1st two characters).