[texhax] unexplained space

[Karl Berry]

                   Some of my macros yield unexpected space to the left and/or
    right of what is the expected return.

I suggest using \loggingall and look for {blank space  } in the .log file
when the macro is expanded.

The rules of when TeX ignores and doesn't ignore whitespace are
explained in the TeXbook (and probably other places), but can't be
summarized in a couple of sentences.

Best,
karl