[Uim] Questions on coding for uim

[Park Jae-hyeon]

Hello,

TOKUNAGA Hiroyuki <tkng at xem.jp> writes:

> 
> > I have a question on writing scheme code for uim, related to bug 1).
> > The second argument of context-update-preedit is a list of pairs of
> > attributes and strings.  According to anthy-input-state-preedit, it
> > seems that the list is also allowed to have #f or '() as one of its
> > elements.  Is it #f or '() that can be an element of the second
> > argument of context-update-preedit?
> 
> attr should be a number which defined in im.scm. i.e. preedit-none, 
> preedit-underline, preedit-reverse, preedit-cursor or preedit-
> separator. If there's no attribute, you should use preedit-none. On the
> other hand, when the segment has no str, you should use "".
> 

My question is something else.  Look at the following procedure from
anthy.scm:

(define anthy-input-state-preedit
  (lambda (ac)
    (let* ((preconv-str (anthy-context-preconv-ustr ac))
	   (rkc (anthy-context-rkc ac))
	   (pending (rk-pending rkc))
	   (kana (anthy-context-kana-mode ac))
	   (rule (anthy-context-input-rule ac))
	   (extract-kana
	    (if (= rule anthy-input-rule-kana)
		(lambda (entry) (car entry))
		(lambda (entry) (nth kana entry)))))

      (list
       (and (not (ustr-cursor-at-beginning? preconv-str))
	    (cons preedit-underline
		  (string-append-map-ustr-former extract-kana preconv-str)))
       (and (> (length pending) 0)
	    (cons preedit-underline pending))
       (and (anthy-has-preedit? ac)
	    (cons preedit-cursor ""))
       (and (not (ustr-cursor-at-end? preconv-str))
	    (cons preedit-underline
		  (string-append-map-ustr-latter extract-kana preconv-str)))))))

The result is a list with four elements.  Each element can be either a
pair or #f depending on the first argument passed to and.  So I guess
that #f is ignored by context-update-preedit.  Because the current
scheme interpreter does not distinguish between #f and '(), I am
wondering about the exact spec of context-update-preedit.  Does it
ignore #f, '(), or both?

Regards,

Jae-hyeon