bug#61221: 30.0.50; [PATCH] Support completion of quoted variable refs in Eshell

[Jim Porter]

X-Debbugs-Cc: monnier@iro.umontreal.ca

Eshell lets you put quotes around variable names so that the parser can 
tell where the name ends, sort of like ${var} in other shells:

  ~ $ echo $'user-login-name'-suffix
  user-suffix

  ~ $ echo $"user-login-name"-suffix
  user-suffix

However, you can't tab-complete variable names when you do this. Here's 
a fix. I also fixed a couple small issues with completing directory 
names where it would sometimes complete to "whatever/ ". That extra 
trailing space isn't helpful, since you'd have to delete it before 
typing in a subdir.

Probably the most controversial part of this patch is in #0002, where I 
added another dynamic variable 'pcomplete-exit-function' that Pcomplete 
handlers can set to tell Pcomplete what to do after exiting a 
completion. Maybe it would be better to have handlers throw some special 
value for 'pcomplete-completions' that contains this info (sort of like 
the value that a 'completion-at-point-function' returns). I'm not sure 
what the best (and most-compatible) way to do this would be...

0001-Throw-strings-as-the-values-for-eshell-incomplete.patch
Description: Text document

0002-Add-support-for-completing-quoted-variables-in-Eshel.patch
Description: Text document

0003-Don-t-add-a-space-after-the-trailing-slash-when-comp.patch
Description: Text document