#84 Operator to get the current iteration

[Martin Büttner]

One of the most annoying things (among common tasks) in CJam is keeping track of loop iterations. Sometimes, you can keep a running total on the stack and do something like \)\, but more often than not, you'll need a variable and do something like I):I, and then you usually want to use W for that, killing your precious -1 variable. For the purpose of counting loops when you just want the total at the end, it's actually shortest to spam the stack by leaving one element on each iteration, and then doing something like ],( at the end. That's pretty messy and not very efficient either.

Long story short, CJam could really use an operator which gives you the current iteration inside the loop, and the total number of iterations of the last loop when you're outside. I actually think this would be so incredibly useful that one of the remaining 1-char commands should be used up for this.

To make this work better with nested loops one could also add a 2-char command which pushes all the iteration counters of the surrounding loops. E.g. if you're iterating over a grid, then the command would push either x y or y x. It's probably golfier to put the inner most loop on top of the stack, such that you can get only the one below with a single discard operation. (Getting only the inner most one can be done with the 1-char command.)