On Sat, 15 Oct 2011, Hans Hagen wrote:

> On 15-10-2011 03:13, Aditya Mahajan wrote:
>> On Wed, 21 Sep 2011, Wolfgang Schuster wrote:
>>> Am 21.09.2011 um 05:20 schrieb Aditya Mahajan:
>>> 
>>>> The following works in MkIV but fails in MkIV:
>>>> 
>>>> \unprotect
>>>> \def\!!yesandon{yes,on}
>>>> \doifinsetelse{yes}\!!yesandon
>>> 
>>> \ExpandSecondAfter\doifinsetelse{yes}\!!yesandon
>>> 
>>> It’s awkward but this how it works in MkII.
>> 
>> \ExpandSecondAfter is MkII only, so I cannot use it for code that is to
>> be used in both MkII and MkIV. So, I re-request my original proposal:
>> 
>> in core-gen.mkii
>> 
>> \def\p!doifinsetelse#1#2#3#4%
>> {\donefalse
>> \edef\!!stringa{#3}%
>> \ifx\!!stringa\empty
>> \else
>> - \processcommalist[#4]\p!docheckiteminset
>> + \processcommacommand[#4]\p!docheckiteminset
>> \fi
>> \ifdone\expandafter#1\else\expandafter#2\fi}
>
> I cannot oversee the consequences of that.
>
> Can't you wrap your call in
>
> \expanded{\doifinsetelse{...}{...}} {} {}
>
> this should work in both mk's

No. Not without a lot of \noexpand. I'll add a macro that expands to 
\ExpandSecond after in MkII and \relax in MkIV.

Aditya