# [texhax] unexplained space

Karl Berry karl at freefriends.org
Tue May 8 22:59:36 CEST 2007

Out of curiosity, I've always wondered whether there are any
circumstances where this would hurt

Yes, but the circumstances are relatively obscure.  The example I recall
from the TB is when TeX is looking for a <space>, the code following is
expandable (\if..., in that case), and it's happening inside an
alignment template.

I've also seen issues when the <space> following a filename (e.g., for
\font or [primitive] \input) is not explicitly present and the following
code is expandable.

Personally, I mostly learned the rules (insofar as I have learned them :)
by looking for {blank space  } in the log files, as I wrote.  That
makes it entirely obvious.

k