[latex3-commits] [git/LaTeX3-latex3-latex3] master: add explanation why hack in tl_if_head_eq_meaning:nN is fine (c4a0d94b8)

[Bruno Le Floch]

Repository : https://github.com/latex3/latex3
On branch  : master
Link       : https://github.com/latex3/latex3/commit/c4a0d94b87d4624c3715454568f698e6756b0b9b

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commit c4a0d94b87d4624c3715454568f698e6756b0b9b
Author: Jonathan Spratte <jspratte at yahoo.de>
Date:   Sat Sep 19 22:17:52 2020 +0200

    add explanation why hack in tl_if_head_eq_meaning:nN is fine


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c4a0d94b87d4624c3715454568f698e6756b0b9b
 l3kernel/l3tl.dtx | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/l3kernel/l3tl.dtx b/l3kernel/l3tl.dtx
index 5f97365c8..5f18e6c60 100644
--- a/l3kernel/l3tl.dtx
+++ b/l3kernel/l3tl.dtx
@@ -3113,7 +3113,8 @@
 %   the normal case, use \cs{tl_head:w}, with no \cs{exp_not:N} this
 %   time, since \cs{if_meaning:w} causes no expansion.  With an empty
 %   argument, the test is \texttt{true}, and \cs{use_none:nnn} removes
-%   |#2| and the usual \cs{prg_return_true:} and \cs{else:}.
+%   |#2| and \cs{prg_return_true:} and \cs{else:} (it is safe this way here as
+%   in this case \cs{prg_new_conditional:Npnn} didn't optimize these two away).
 %   In the special cases, we know that the first token is a character,
 %   hence \cs{if_charcode:w} and \cs{if_catcode:w} together are enough.
 %   We combine them in some order, hopefully faster than the reverse.