Re: [dev] Simple made Easy (Rich Hickey at StrangeLoop)

From: Anthony Martin <ality_AT_pbrane.org>
Date: Sat, 22 Oct 2011 03:13:36 -0700

Connor Lane Smith <cls_AT_lubutu.com> once said:
> So I think the necessary next step would be to have a strongly typed
> shell. To pretty-print you'd need to add a polymorphic "à la carte"
> (multiple dispatch) pretty-printing function for the given data type.
> The type inference would be done per command, so cat(1) would be of a
> type such that if you were to try catting an image (directly) to wc(1)
> it would fail, because the types (Image, String) would not match. You
> could also have awesome higher-order functions, so 'map' would remove
> the need for find(1), etc.

Then someone will ask for sub-typing and someone
else will want ADTs and we'll wake up one day and
have to learn category theory just to use a shell. :)

A while ago I thought about doing something similar
in a more general way. Say we modified the Plan 9
pipe(2) system call to check the current process's
namespace for /dev/pipe instead of using the hard-
coded pipe(3) device. This would allow us to build
custom type-safe pipes as user-space filesystems.

You could then do something like:

% jsonpipefs -m /mnt/json
% ls /mnt/json
data
data1
% bind /mnt/json /dev/pipe
% produce | consume # these commands expect a serialized JSON stream

The beauty of this is that the stream typing logic
is separated from individual programs and, of course,
the shell.

Cheers,
  Anthony
Received on Sat Oct 22 2011 - 12:13:36 CEST