On 23 May 2014, at 6:10 am, Joseph Wright <[log in to unmask]> wrote:

>> 
>> Shouldn't we just allow spaces (and leading | or any other system
>> dependent special
>> syntax) just surrounding any user supplied name by " " to keep it together?
> 
> Space behaviour notwithstanding, I think the point here is that the pipe
> input approach is sufficiently different from a 'real' file to deserve a
> separate interface.

One big difference being I think, which I’m stealing from a tex.sx comment I read recently (sorry for the lack of attribution — maybe Heiko?), being that MiKTeX explicitly requires a “-enable-pipes” option passed to pdfTeX to function whereas TeX Live permits pipes with -shell-escape.

I could be wrong but I think this is a bit of an issue because shell-escape-being-enabled can be queried within pdfTeX whereas MiKTeX support for pipes can’t be. This makes it difficult/impossible (?) to provide an equivalent expl3 interface on all platforms.

Having said all this, I think one reason pipes haven’t been used much since their initial inception is a lack of obvious documentation and good user interface. So providing some higher-level support for this functionality could be good incentive to normalise the interface between MiKTeX and TeX Live.

Cheers,
Will