Is it possible to redefine the character code of space?

Question

If I execute the code \tt\catcode` =12\relax test I get:

I also can emulate the same effect using \char32 in place of <space>. Is it possible to change the character code of <space>, so that when I type \tt\catcode`\ =12\relax test there is another character displayed there? For example, whenever I type <space> it displays !, which is \char33?

One way is to make the space an active character then def it to char33 (read e.g. TeXbook/TeX by Topic if this doesn't make sense) — user202729, Jun 29 '22 at 01:51
XeTeX has some alternatives e.g. fonts - Replace a single letter in xelatex - TeX - LaTeX Stack Exchange — user202729, Jun 29 '22 at 01:52
Look at the linked questions (and the double-indirect-linked questions) from that one for alternatives. For example https://tex.stackexchange.com/a/498250/250119 for LuaTeX. — user202729, Jun 29 '22 at 01:58

score 1 · Answer 1 · answered Jun 29 '22 at 13:42

1

Plain TeX offers \obeyspaces that simply declares the space character to be active.

\obeyspaces\def {!}%
\tt test
\tt^^@test test
\bye

answered Jun 29 '22 at 13:42

egreg

1,121,712

Thou shalt obey thy spaces! – Gaussler Jun 29 '22 at 14:18

score 0 · Answer 2 · answered Jun 29 '22 at 06:08

0

Inspired by user202729's comment, I have done the following:

\begingroup\lccode`~=` \lowercase{\endgroup\obeyspaces\let~=!\relax}
\tt test
\bye

Note the \lowercase trick to trick TeX into using an active space in the definition \let~=!.

answered Jun 29 '22 at 06:08

btshepard

680

Is it possible to redefine the character code of space?

2 Answers2

Linked