On 14/07/2015 10:19, Ulrike Fischer wrote:

> Am Tue, 14 Jul 2015 09:42:13 +0100 schrieb Joseph Wright:

> 

>> I was thinking of

>>

>>     \keys_define:nn {test}

>>       {

>>         testa .code:n = {\tl_show:n {#1}},

>>         testa .value_required:,

>>         testb .code:n = {\tl_show:n {#1}},

>>         testb .value_required:,

>>         testb .default:n = {}

>>     }

>>

>>     \keys_set:nn {test} {testa,testb}

>>

>> where one might expect to get an error only in the first case. That's

>> not currently the situation!

> 

> Hm. My first reaction was that it works as expected. If I explictly

> require that the *user* gives a value, a *package* default doesn't

> make sense and shouldn't replace the user action.



That's entirely logical and as you say what currently happens, it's just

it's not documented (or I think tested). I'll address that so we have a

clear position :-)



> It is also consistent with the other way round:

> 

> \documentclass{article}

> \usepackage{expl3}

> \begin{document}

> \ExplSyntaxOn

>   \keys_define:nn {test}

>       {

>         testb .code:n = {#1},

>         testb .value_forbidden:,

>         testb .default:n = {xxx}

>     }

> 

>    \keys_set:nn {test} {testb}

> 

> \end{document} 



Again, probably should document this.



Time-allowing I will do an update to l3keys today to address all of the

points raised.

--

Joseph Wright