[NTG-pdftex] \expanded

Taco Hoekwater taco at elvenkind.com
Mon Dec 10 11:44:34 CET 2007

Heiko Oberdiek wrote:
> Hello,
> On Sun, Dec 09, 2007 at 08:14:31PM +0100, Morten Høgholm wrote:
>> Usually the x expansion meant "uses \edef" and so they were all  
>> non-expandable. But now that we have pdfeTeX'ed the l3 kernel, we have  
>> functions doing full expansion like \numexpr and friends and \pdfstrcmp  
>> (does \edef on both arguments) used in \tlist_if_eq:xxTF. This reminds me:  
>> the notes from the Oldenburg meeting mentions an \expanded primitive:
>>   \expanded <general text>
>>   Expandable command returning the full expansion
>>   of the tokens in <general text>.
>> So since this pretty much exists inside \pdfstrcmp as it is now, it could  

Can someone please post an example of intended use in the
l3 kernel in "plain"-style, just so I understand the usage?

>> Any opinions from the ConTeXt/pdfTeX people here?

ConTeXt's \expanded macro expands its argument fully except
for the very first item in it, which is handy for macros that
need expanded arguments, so I assume the actual goals are very
similar. Its definition is essentially this:


With the new primitive, it could be rewritten as:


> Biggest problem is probably a good name:
> a) \expanded would be a nice name, but it clashes with ConTeXt.
>    I remember trouble with \unexpanded :-(
> b) It would belong to e-TeX, but there isn't a e-TeX prefix:
>    \etexexpanded or \etexexpand
> c) pdfTeX's convention with prefix "\pdf" (see \pdfstrcmp, \pdfescape*):
>    \pdfexpanded or \pdfexpand
> d) longer names
> My preference is c) to avoid trouble with macro name clashes.
> I can live with a), then my package etexcmds would get a
> new macro \etex at expanded.

Hans and I think a) would be fine. c) is somewhat silly as it is
not related to pdftex, and also a) combines nicely with the already
present \unexpanded.

Best wishes,

More information about the ntg-pdftex mailing list