PATCH [1/1]: compressedand - escape single ampersand found in URLs

[Gonzalez, Eric (UMKC-Student)]

I've written a feature I find useful for bash that escapes a single ampersand 
if it is surrounded on both sides by any non-blank or non-meta characters. This 
logic is toggled by a set option, "compressedand" that can be enabled with `set 
[-|+]c` or `set -o compressedand`.


As an example:

   $ echo this&echo that
   [1] 32324
   that
   this
   [1]+  Done                    echo this

   $ set -c
   $ echo this&echo that
   this&echo that

Handling of multi-character metas, such as &>, |&, &&, et al, is still parsed 
by BASH and their functions remain unaffected.

   $ echo this& echo that
   [1] 1373
   that
   this
   [1]+  Done                    echo this

   $ echo this &echo that
   [1] 1375
   that
   this
   [1]+  Done                    echo this

   $ echo this&&echo that
   this
   that

   $ ps ax&>/tmp/ps&echo
   $ ls /tmp/ps\&echo
   /tmp/ps&echo


The primary use case for the option is to ease using unquoted URLs as arguments 
that have multiple query parameters. Yes, quoting the URL precludes the need 
for this feature, but I forget sometimes (okay, too often):

   $ set +c
   $ echo https://example.com/inputs?v=22&time=now&cp=key
   [1] 32335
   [2] 32336
   https://example.com/inputs?v=22
   [1]-  Done                    echo https://example.com/inputs?v=22
   [2]+  Done                    time=now

   $ set -c
   $ echo https://example.com/inputs?v=22&time=now&cp=key
   https://example.com/inputs?v=22&time=now&cp=key


I've attached a patch that was written against bash-4.4 and tested to work 
against the most recent DEVEL commit (3235014e5b) as of 04/22. The patch 
provides the logic, set option control, and updates to the man and info pages. 
I'm still working on getting some tests worked up. I wanted to get this 
submitted to get a feel for general likeability and for input on things I need 
to do for a proper contribution.

And, for completeness, here are the bash VERSIONs I've tested this on:

   GNU bash, version 4.4.23(1)-release (x86_64-pc-linux-gnu)
   GNU bash, version 5.0.16(1)-maint (x86_64-pc-linux-gnu)

I haven't looked up to see what POSIX has to say about this, but I'm fairly 
confident that this flies in the face of it. If that's the case and this patch 
is dismissed accordingly, I'll accept that. This was a fun exercise anyway.  .)

- Eric.

-------------------------------
Fudd's First Law of Opposition:
"If you push something hard enough, it will fall over."
          - Firesign Theater

bash-4.4-escape-compressed-ampersand.patch
Description: bash-4.4-escape-compressed-ampersand.patch