Confusion in discussion about `a` and `n` in macros-practical example

[wpd]

The example contains the statement:

This changes the definition of a to:

let a = IndexOffset { slice: &self.mem, offset: n };

I don't see where a was defined prior to that statement.
Similarly, shortly after that, you wrote:

Note that I've changed the order of the declarations of n and a, as well as wrapped them(along with the recurrence expression) in a block.
I don't see n or a in the code that precedes that.

[Veykril]

a and n are introduced in the code block after the We need a branch to yield the initial values of the sequence; nothing tricky. line. Needless to say, the variable names could and probably should be something more descriptive than a or n.

[wpd]

Note to self... don't press the "Comment" button in GitHub until you've gone to sleep, gotten up the next morning, and looked at the code again. I now see that somehow during the night (without pushing any changes to GitHub), pixies snuck in and added some code to your example. Today, I see:

let a = /* something */;
let n = self.pos;

I swear that wasn't there last night! (It was).
I'm sorry for the noise.