Anyone know how to pass a constant into a loop?

I have a script that refers to the same contant value a few times, in loops, and rather than have each reference be a literal, I want a single constant that I can change in one place. Given /t/8897/1, I can't use a variable for this.

My best alternative is placing the value in a spare field of every track... which fails if the track file are RO.

Any other ideas?