Autoclose GNU Readline

Question

Working on various GNU Readline-based CLIs and it would dramatically speed me up if there was a way to have brackets and quotes automatically closed when you type.

Thus typing a ' or ( on Bash (or other CLIs) would actually append the closing quote or bracket '' or () and place the cursor inbetween for writing.

I've looked around for quite some time trying to find out anything related (e.g. ~/.inputrc setting), but didn't find anything and I wonder if that's at all achievable. Any comments would be appreciated.

Answer 1

It's a bit tricky, but doable. As a bash command:

bind '"(" "\C-v()\e[D"'
bind '"\"" "\C-v\"\C-v\"\e[D"'

As a setting in .inputrc (so any program using readline gets the behavior):

"(": "\C-v()\e[D"
"\"": "\C-v\"\C-v\"\e[D"

You can prefix each key with Control-v to type "plain" quotes and left parentheses without triggering the auto-close behavior.

The above assumes Emacs keybindings. For vi bindings, use

bind '"(": "\C-v()\ei"'
bind '"\"" "\C-v\"\C-v\"\ei"'

or

"(": "\C-v()\ei"
 "\"": "\C-v\"\C-v\"\ei"

Essentially, just replace the [D with i; instead of sending the escape sequence to move the cursor left, just send \e to drop back into command mode after inserting the parentheses/quotes, then re-enter insert mode, which should position the cursor inside the characters just typed.

Answer 2

Doing exactly what you want is impossible, but there is a work around. Put this in inputrc:

"\C-x\"": "\"\"C-b"

Run:

info readline "comm" "readline init" "sample"

for the whole sample.