Re: Completion problems.

["Bart Schaefer" <schaefer@xxxxxxxxxxxxxxxxxxxxxxx>]

On Aug 4, 11:37am, Sven Wischnowsky wrote:
} Subject: Re: Completion problems.
}
} Tanaka Akira wrote:
} 
} > In following examples, unquoted forms are not known until runtime.
} > 
} > % if some-complex-command; then var=xxx; else var=yyy; fi; tst $var/<TAB>
} > % tst $(some-complex-command)/<TAB>
} 
} I see two ways to go: 1) completely change the completion code to
} report strings in unquoted form or 2) add a parameter expansion
} modifier which does something like the opposite of `:q'.

I think (2) would be quite useful in other contexts anyway.  Perhaps (Q)?
(And we could add (q) which means the same as :q, just for completeness.)

There is some question about what paramter unquoting should do in the case
of mismatched quotes.  I can think of cases where you'd want it to produce
the same errors as using that same quoting in a command, and other cases
(like completion) where you'd just like it to assume the closing quote.

} [...] with match specs using `*'-patterns new stuff can be inserted
} anywhere in the word. To retain the single quotes the completion code
} would have to keep track of the original positions and would have to
} calculate the new positions for every single or double quote inside
} the word. This is extremly difficult, expensive (i.e. slow), and at
} least I wouldn't implement it (if anyone else is interested: try to
} find out how the completion code now handles completion inside braces
} -- you would have to do something similar, but not only for two
} places, but for a whole list of positions).

I almost hate to mention this, but braces can be nested, and right now
completion doesn't work in that case -- presumably *because* it isn't
keeping track of a list of positions.

There are similar (?) problems with nested parameter substitutions:

zagzig<1> echo ${${p<TAB>
path     perl     prompt   psvar           
zagzig<1> echo ${${pa<TAB>
zagzig<1> echo ${${path} 
                         ^Cursor is now here; arguably no space should
                          have been added, because it can't possibly be
                          correct in that context.  Also, if you now type
                          a right-curly, the trailing space is deleted,
                          but the right-curly is not inserted (which I
                          guess is theoretically correct).

BTW, expand-or-complete is a pain in the butt when combined with braces,
because as soon as you close the braces the next TAB *expands* them,
leaving you with multiple half-finished words.  You can prevent this by
setting GLOB_COMPLETE, but in that case completion after the right-brace
still doesn't work.

-- 
Bart Schaefer                                 Brass Lantern Enterprises
http://www.well.com/user/barts              http://www.brasslantern.com