Re: Proposal for extending set-process-filter

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Give PROCESS the filter function FILTER; nil means no filter.

What happens to output when there's no filter?

> 1) a function which gets two arguments. [insert old description]

Good.

> 2) a buffer into which output gets inserted.

Good.

> 3) a file name for output.

Can be handled by (1) just fine.  What would you use it for (other than
/dev/null which is rather special since append is the same as overwrite)?

> 4) t to stop accepting output.

What happens to the output?  Is it read&thrown away or not read?

> 5) a list of filter/file descriptor associations.
> The car's of the elements of this list are an item from 1)-4) as
> above, while the cdr is a list of file ids for which this item is
> supposed to apply.

Sounds good.

> This does not yet do everything needed for a full-bodied eshell: input
> redirections (including procedural input, equivalents to filter
> functions) and output appending redirection (>>) are not covered
> yet.  But it would be a first step.

Output-appending can be done via a filter-function.
What kind of procedural input are you thinking of that can't be done via
process-send-string?

What is still missing is the ability to open more file descriptors than
stdin, stdout, stderr.


        Stefan