On Thu, Sep 18, 2008 at 01:31:20PM +0100, Joseph Wright wrote:

> To save everyone a little time, how about the following for a
> comprehensive set (following the \char_if_<whatever> names where available):

> [Definition text omitted in the following]

In comments I have added the words from the column "Meaning"
in "The TeXbook", chapter 7, page 37:

> \def_new:Npn \char_make_escape:N #1 {
% Escape character

> \def_new:Npn \char_make_begin_group:N #1 {
% Beginning of group

> \def_new:Npn \char_make_begin_end:N #1 {
% End of group

==> \char_make_end_group

> \def_new:Npn \char_make_math_shift:N #1 {
% Math shift

> \def_new:Npn \char_make_alignment:N #1 {
% Alignment tab

> \def_new:Npn \char_make_end_line:N #1 {
% End of line

> \def_new:Npn \char_make_parameter:N #1 {
% Parameter

> \def_new:Npn \char_make_math_superscript:N #1 {
% Superscript

> \def_new:Npn \char_make_math_subscript:N #1 {
% Subscript

> \def_new:Npn \char_make_ignore:N #1 {
% Ignored character

> \def_new:Npn \char_make_space:N #1 {
% Space

> \def_new:Npn \char_make_letter:N #1 {
% Letter

> \def_new:Npn \char_make_other_char:N #1 {
% Other character

> \def_new:Npn \char_make_active_char:N #1 {
% Active character

> \def_new:Npn \char_make_comment:N #1 {
% Comment character

> \def_new:Npn \char_make_invalid:N #1 {
% Invalid character

> [...]
> \char_make_other:N \$

But above you have defined \char_make_other_char.
In general I think, where Knuth has written "xy character"
the word "character" could be omitted, because it is already
present as first compound of the macro. Also it would make
the macro name a little shorter. In part you have done it already:

\char_make_escape
\char_make_ignore
\char_make_comment
\char_make_invalid

but

==> \char_make_other
==> \char_make_active

Yours sincerely
  Heiko <[log in to unmask]>