In latex.ltx
you can find several situations where \escapechar
is set to -1 -- from what it's clear that it has to be a count register. But, what does it actually "count" or control? A small discussion of an example like the following could be useful too.
\def\renew@command#1{%
\begingroup \escapechar\m@ne\xdef\@gtempa{{\string#1}}\endgroup
\expandafter\@ifundefined\@gtempa
{\@latex@error{\noexpand#1undefined}\@ehc}%
\relax
\let\@ifdefinable\@rc@ifdefinable
\new@command#1}
\escapechar
: Number of the character that is to be used for the escape character when control sequences are being converted into character tokens. IniTeX default: 92 (\
).\escapechare
is not a\count
register (or, better, a\countdef
token), but an <integer parameter> (thus, a TeX primitive), listed among the others on page 273 of The TeXbook.\escapechar
"strips" the backslash away in the definition of\renew@command
)?