Re: Re: [nbdev] Question: Expand Abbreviations action in Java Editor

Tor Norbye wrote:

> Sandip Chitale wrote:
>
>> Can anyone explain how the Expand Abbreviations [abbrev-expand] 
>> action in Java Editor works?
>>
>> Here is the scenario:
>> I bound a key stroke (Ctrl+Enter) to Expand Abbreviations 
>> [abbrev-expand]  action in Java editor key bindings options.
>> [I could not
>>
>> I have an abbrev:
>>
>> foria
>>
>> which should expand to:
>>
>> for (int i = 0; i < |.length; i ++) {
>> }
>>
>> Now when I type:
>>
>> foria<SPACE>
>>
>> the abbreviation expands correctly. This seems to be an implicit key 
>> binding.
>>
>> foria<Ctrl+Enter>
>>
>> the abbreviation expands correctly too.
>>
>> However if I type any char like backspace then the abbrev expansion 
>> does not work e.g.
>>
>> foris<BACKSPACE>a<Ctrl+Enter>
>>
>> then the abbreviation does not expand.
>>
>> I think the Expand Abbreviations [abbrev-expand] should work as long 
>> as the text (word?) before the caret matches  an abbreviation.
>>
>> Comments? 
>
>
> My guess is that this was done as a usability fix for those cases when 
> you DON'T want the abbreviation. That's not likely with Ctrl+Enter but 
> is likely with space.
>
> Let's say you wanted to type the phrase "we're " in a comment. Since 
> "re " is an abbreviation for "return" you end up with "we'return ". 
> Now you go back and delete it to "we're" and hit space to continue - 
> if it always expanded this would become "we'return" again!
>
Yes. I understood that something like that might have been the reasoning 
behind it. However there are several problems with the approach. The 
SPACE to expand abbrevs as an *implicit* binding is not good. IMHO that 
should be under user control. Secondly it is inefficient.  (My agues is) 
the editor is trying to match the expansion prefix almost every keystroke.

Like you observed the problem you describe definitely apply to an 
explicitly defined key binding like (Ctrl+Enter) as the user will have 
to invoke it explicitly to trigger expansion.

I have filed the following RFE here:

http://www.netbeans.org/issues/show_bug.cgi?id=57856

In it I have suggested use of the

javax.swing.text.Utilities.getPreviousWord(JTextComponent editor, int 
caretOffset)

to look at the word before the caret to match the abbrev prefix, as one 
way to solve the problem. That however assumes that abbrev prefixes are 
words in that editor kit's type's domain.

(X)Emacs solves this problem in several different ways:

1. User can globally/per file type/per file/per buffer control whether 
abbrevs expand or not. This may be an overkill for NetBeans. A global 
switch for each file type may be sufficient.
2. SPACE is not implicitly bound to expand abbreviations action.
3. There is a enter quoted following char mechanism using Ctrl+Q. I 
think same is true in Vi.

Finally, IIRC, Eclipse simply takes a unified approach to:

1. Code completion
2. Template expansion
3. Abbrev expansion

I guess 2 and 3 are same in Eclipse.

It is not a coincidence that abbrev bugs in NetBeans get filed again 
code completion :-)

Here is another RFE related to the above point:

http://www.netbeans.org/issues/show_bug.cgi?id=56891

--
Sandip

> So I'm guessing the abbreviations code is only doing abbreviation 
> expansion if you type the abbreviation correctly - if you edit around 
> it it doesn't.
>
> (This is just speculation but I don't want it to start expanding 
> always for the case when space is used as the expand key)
>
> -- Tor
>
>
>