[tex-k] A041: \uppercase and \lowercase not respecting the invariant of space tokens having character code 32

Karl Berry karl at freefriends.org
Fri Oct 13 00:32:16 CEST 2023

Hi Tyge,

    This seems to me to be an inconsistency in both "The TeXbook" and
    "TeX: The Program".

Isn't this what Knuth explains on page A377? He uses the term ``funny
space'' tokens for tokens with catcode 10 and charcode != 32.

    In "The TeXbook" in chapter 8 on page 47, it states that "the
    character code in a space token is always 32"

I guess it's a lie :(. I imagine he didn't want to get into these gory
details of different kinds of space tokens in such an early chapter.
Especially since they serve no practical purpose (as far as I know).

As for tex.web, I feel sure he would deem it undesirable to change any
behavior wrt space tokens at this late date ... 

Thanks for the report,

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