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The last expl3 update broke my "continue" detection for the index. Here is a MWE: (EDIT: I realized it is possible to reduce it even further)


\cs_generate_variant:Nn \tl_if_eq:nnTF { xxTF }

    \tl_if_eq:xxTF { me } { you }



When running it the error message is:

! Undefined control sequence.
<argument> \::T


If I use \tl_if_eq:nnTF then it compiles. But I need to expand the arguments, and it did work before the last update. How can I fix this now? What is the reason?

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closed as off topic by Marco Daniel, lockstep, Tom Bombadil, percusse, diabonas Aug 26 '12 at 13:38

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I actually had the same error a while back. I assumed I wasn't allowed to define a variant with the following TF because I hadn't had a working version previously. – Scott H. Aug 26 '12 at 1:24
This is a bug report rather than a question; as such, it would be more appropriate on the LaTeX-L mailing list (see latex-project.org/code.html) than here. See meta.tex.stackexchange.com/q/2622/2966 for discussion of this policy. – J. C. Salomon Aug 26 '12 at 4:02
oh, sorry. I will send an email as well then. – MiB Aug 26 '12 at 5:52
I forget how I resolved the issue. At worst you can probably use \tl_set:Nx to expand the the arguments and then pass the resulting tl's to \tl_if_eq:NNTF. – Scott H. Aug 26 '12 at 6:07
Logged as github.com/latex3/svn-mirror/issues/100 – Joseph Wright Aug 26 '12 at 6:29
up vote 7 down vote accepted

In addition to the point tohecz makes, you don't really need the TF here, which is probably why we've not picked this up in testing. I would do simple

\cs_generate_variant:Nn \tl_if_eq:nnTF { xx }
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Aha, that does work indeed, thanks! It's not documented though ;) – MiB Aug 26 '12 at 6:19
Agreed, and commented that on the issue tracker. I'll look at it soonish. – Bruno Le Floch Aug 26 '12 at 21:21

This is basically a bug in LaTeX3 and as such, it should be reported using the way explained by J. C. Salomon in the comments.

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