Re: ${(k)widgets} v. 'zle -la'

[Daniel Shahaf <d.s@xxxxxxxxxxxxxxxxxx>]

Bart Schaefer wrote on Thu, Jul 07, 2016 at 09:49:21 -0700:
> On Jul 7,  2:00am, Daniel Shahaf wrote:
> }
> } Is the following behaviour also intentional?  Testing a key's presence
> } in the associative array in different ways gives different results:
> } 
> }     % bindkey foo bar
> }     % () { print $(( $argv[(I)bar] > 0 )) } ${(k)widgets}
> }     1
> }     % print ${+widgets[bar]}
> }     0
> 
> It's intentional in that hash table entries are parameter values and
> parameters can exist but be unset, like declaring something local and
> then unsetting it; $widgets[bar] returns a "value" that is equivalent
> to "unset" when the widget doesn't exist.
> 

*nod*

> It's not intentional in that for normal hash tables there's no way to
> create such an entry, so the ramifications on e.g. ${+...} of having
> a special hash where a key that is present is only a placeholder, were
> not fully thought through.

*nod*

For future reference, attempting to creating such an entry generates the
following error:

% typeset -A h=(k1 v1 k2 v2)
% () { local 'h[k1]' }
(anon):local: h[k1]: can't create local array elements

> On the other hand it's the only result that accurately represents the
> situation.

I've been wondering about a docs patch for this.  Does the following make
sense?

Unidiff:

    diff --git a/Doc/Zsh/mod_zleparameter.yo b/Doc/Zsh/mod_zleparameter.yo
    index 03d5047..76d23ba 100644
    --- a/Doc/Zsh/mod_zleparameter.yo
    +++ b/Doc/Zsh/mod_zleparameter.yo
    @@ -15,14 +15,16 @@ This array contains the names of the keymaps currently defined.
     )
     vindex(widgets)
     item(tt(widgets))(
    -This associative array contains one entry per widget defined. The name 
    +This associative array contains one entry per widget. The name 
     of the widget is the key and the value gives information about the
    -widget. It is either the string `tt(builtin)' for builtin widgets, a
    -string of the form `tt(user:)var(name)' for user-defined widgets,
    -where var(name) is the name of the shell function implementing the
    -widget, or it is a string of the form
    -`tt(completion:)var(type)tt(:)var(name)', for completion widgets. In
    -the last case var(type) is the name of the builtin widgets the
    +widget. It is either
    +  the string `tt(builtin)' for builtin widgets,
    +  a string of the form `tt(user:)var(name)' for user-defined widgets,
    +    where var(name) is the name of the shell function implementing the widget,
    +  a string of the form `tt(completion:)var(type)tt(:)var(name)'
    +    for completion widgets,
    +  or a null value if the widget is not yet fully defined.
    +In the penultimate case, var(type) is the name of the builtin widget the
     completion widget imitates in its behavior and var(name) is the name
     of the shell function implementing the completion widget.
     )

That diff reindents, so here's an equivalent wdiff [should be easier to review]:

    @@ -15,14 +15,16 @@ This array contains the names of the keymaps currently defined.
    )
    vindex(widgets)
    item(tt(widgets))(
    This associative array contains one entry per [-widget defined.-] {+widget.+} The name 
    of the widget is the key and the value gives information about the
    widget. It is either
      the string `tt(builtin)' for builtin widgets,
      a string of the form `tt(user:)var(name)' for user-defined widgets,
        where var(name) is the name of the shell function implementing the widget, [-or it is-]
      a string of the form
    [-`tt(completion:)var(type)tt(:)var(name)',-] {+`tt(completion:)var(type)tt(:)var(name)'+}
        for completion [-widgets.-] {+widgets,
      or a null value if the widget is not yet fully defined.+}
    In the [-last case-] {+penultimate case,+} var(type) is the name of the builtin [-widgets-] {+widget+} the
    completion widget imitates in its behavior and var(name) is the name
    of the shell function implementing the completion widget.
    )

[syntax highlighting for that is ':setf wdiff' in vim; no idea about others]