How to match a number range, the right way

[aarmn]

I was working on an educational asm parser, and many times I came across the same concept: I had to check validity of an instruction by checking is it in a specific range of nums (e.g. 0~255) or not
To do so for a base 10 number with n digits, I had to make n rules sometimes, tho it's easy to make a python script to fix it, and many times its less than that, but it sounds a bit unintuitive that I cant find a tool for such a common usecase, so that caused my to ask the following questions, which right now, I have no answer for:

Is there a tool out there in pest to fix this more cleanly?
Is it efficient "runtime speed"wise to fix it like that?
can there be an add-on for pest files to fix this issue? or some sort of function call inside pest system for extensibility? (preferably inside pest files not a hack in rust)

Thanks in advance