Peter Slížik wrote on Wed, 23 Sep 2020 10:34 +0200:
> Hello,
>
> I'd like to replicate the functionality found in some text editors - namely
> that if you press a single or double quote, the editor inserts two of them
> and places the cursor inside the pair.
>
> With some necessary checks for word boundaries, etc. left out, the solution
> looks rather trivial:
>
> function insert-single-quotes() {
> zle self-insert "''" # that's "_'_'_"
> zle backward-char
> }
>
> zle -N insert-single-quotes
> bindkey "'" insert-single-quotes # that's "_'_"
>
> However, this solution creates infinite recursion (a single quote bound to
> insert a single quote).
No, it doesn't. I tried in «zsh -f» and it inserts a single quote
without moving the cursor.
It inserts _one_ quote, rather than two, because self-insert ignores
its positional arguments and the widget was bound to «'».
> 1. How to prevent the recursion?
Always open a new shell for testing.
> Is self-insert the right widget for this task?
You could also use «zle .self-insert», or even modify $LBUFFER and
$RBUFFER directly («LBUFFER+=\'; RBUFFER=\'$RBUFFER»).
(Incidentally, I guess you may also want to check whether ${RBUFFER}
starts with a single quote, but that's no longer a zsh question but
a business logic question.)
> 2. I played with zle -U. What are the use cases for zle self-insert and zle
> -U?
«zle -U foo» subjects the «f», «o», and «o» to bindkey mappings. For
instance, «bindkey -s x y» followed by «zle -U x» would insert «y».
«self-insert» appends one character to the buffer.
> 3. I tried to avoid the recursion by using "zle -K .safe -U text", but it
> ended with "too many arguments for -K". How is zle -K expected to be used?
As «zle -K foo» without further arguments. You can do something like this:
{
readonly save_KEYMAP=$KEYMAP
zle -K .safe
⋮
} always {
zle -K $save_KEYMAP
}
But see above about $LBUFFER.
Cheers,
Daniel