;; KHMR-OTF.flt -- Font Layout Table for Khmer OpenType fonts
;; Copyright (C) 2005
;;   National Institute of Advanced Industrial Science and Technology (AIST)
;;   Registration Number H15PRO112

;; This file is part of the m17n database; a sub-part of the m17n
;; library.

;; The m17n library is free software; you can redistribute it and/or
;; modify it under the terms of the GNU Lesser General Public License
;; as published by the Free Software Foundation; either version 2.1 of
;; the License, or (at your option) any later version.

;; The m17n library is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
;; Lesser General Public License for more details.

;; You should have received a copy of the GNU Lesser General Public
;; License along with the m17n library; if not, write to the Free
;; Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
;; 02111-1307, USA.

;;; <li> KHMR-OTF.flt
;;;
;;; For Khmer OpenType fonts to draw Khmer.
;;; A Font is available from 
;;; <http://www.khmeros.info/drupal/?q=en/download/fonts>.

(category
 ;; E : else
 ;; C : consonant & independent vowel
 ;; R : RO
 ;; r : ROBAT
 ;; m : vowel sign (pre)
 ;; b : vowel sign (below)
 ;; a : vowel sign (above)
 ;; A : vowel sign (two-part, above)
 ;; p : vowel sign (post)
 ;; P : vowel sign (two-part, post)
 ;; s : sign (above)
 ;; S : sign (post)
 ;; c : consonant shifter
 ;; H : COENG
 ;; N : ZERO WIDTH NON-JOINER
 ;; J : ZERO WIDTH JOINER
 (0x1780 0x17FF ?E)
 (0x19E0 0x19FF ?E)
 (0x1780 0x17B3 ?C)
 (0x179A	?R)
;; (0x17A3 0x17B3 ?V)
 (0x17B6	?p)
 (0x17B7 0x17BA ?a)
 (0x17BB 0x17BD ?b)
 (0x17BE	?A)
 (0x17BF 0x17C0 ?P)
 (0x17C1 0x17C3 ?m)
 (0x17C4 0x17C5 ?P)
 (0x17C6	?s)
 (0x17C7 0x17C8 ?S)
 (0x17C9 0x17CA ?c)
 (0x17CB 0x17D1 ?s)
 (0x17CC	?r)
 (0x17D2	?H)
 (0x17D3	?s)
 (0x17DD	?s)
 (0x200C	?N)
 (0x200D	?J)
 )

;; Generic syllable pattern is as follows.
;; [CR](r|N?c)?(HCr?)*(HR)?(HCr?)*[NJ]?(m|b|a|A|p|P)?s*S?(H[CR])?

;; Step 0.
;; Move m to the beginning.
;; Split A and P.
;; Exchange the order of pP and s.
;; Move HR before the base.

(generator
 (0
  (cond

   ;; pre vowel sign
   ;;1    2       3       4  5     67            8  9    10
   ("([CR](r|N?c)?(HCr?)*)(HR(r)?)?((HCr?)*[NJ]?)(m)(s*S?(H[CR])?)"
    < |
    (8 =)
    (4 = =)
    (1 = *)
    (5 =)
    (6 = *)
    (9 = *)
    | > )

   ;; two-part above vowel sign
   ;;1    2       3       4  5     67                8
   ("([CR](r|N?c)?(HCr?)*)(HR(r)?)?((HCr?)*[NJ]?As*S?(H[CR])?)"
    < |
    0x17C1
    (4 = =)
    (1 = *)
    (5 =)
    (6 = *)
    | > )

   ;; post vowel sign
   ;;1    2       3       4  5     67            8  9   10 11
   ("([CR](r|N?c)?(HCr?)*)(HR(r)?)?((HCr?)*[NJ]?)(p)(s*)(S?(H[CR])?)"
    < |
    (4 = =)
    (1 = *)
    (5 =)
    (6 = *)
    (9 = *)
    (8 =)
    (10 = *)
    | > )

   ;; two-part post vowel sign
   ;;1    2       3       4  5     67            8  9   10 11
   ("([CR](r|N?c)?(HCr?)*)(HR(r)?)?((HCr?)*[NJ]?)(P)(s*)(S?(H[CR])?)"
    < |
    0x17C1
    (4 = =)
    (1 = *)
    (5 =)
    (6 = *)
    (9 = *)
    (8 =)
    (10 = *)
    | > )

   ;; other vowel signs or no vowel sign
   ;;1    2       3       4  5     67                     8
   ("([CR](r|N?c)?(HCr?)*)(HR(r)?)?((HCr?)*[NJ]?[b|a]?s*S?(H[CR])?)"
    < |
    (4 = =)
    (1 = *)
    (5 =)
    (6 = *)
    | > )

   ("." =))
  *))

;; Now a syllable looks like below.
;; m?(HR)?[CR](r|N?c)?(HCr?)*[NJ]?(b|a|A)?s*(p|P)?S?(H[CR])?

;; Step 1.
;; Set the form of consonant shifter.

(generator
 (0
  (cond
   ;; shifter + above vowel sign without ZWNJ
   ;; Shifter take blwf.  HR takes pref.  HC's take blwf or pstf.
   ;; 1   2    3     4      5     6     7     8
   (" (m)?(HR)?([CR]c(HCr?)*(N|J)?(a|A))(s*S?)(H[CR])? "
    |
    (1 =)
    (2 otf:khmr=pref+)
    (3 otf:khmr=blwf,abvf,pstf+)
    (7 = *)
    (8 otf:khmr=blwf,pstf+)
    | )

   ;; shifter + ZWNJ + above vowel sign, or, shifter without above vowel sign
   ;; Shifter stays above.  HR takes pref.  HC's take blwf or pstf.
   ;; 1   2    3        45       6           7   8     9   10  11
   (" (m)?(HR)?([CR]N?c)((HCr?)*)([NJ]?[ba]?)(A)?(s*p?)(P)?(S)?(H[CR])? "
    |
    (1 =)
    (2 otf:khmr=pref+)
    (3 = *)
    (4 otf:khmr=blwf,pstf+)
    (6 = *)
    (7 otf:khmr=abvf+)
    (8 = *)
    (9 otf:khmr=pstf+)
    (10 =)
    (11 otf:khmr=blwf,pstf+)
    | )

   ;; no shifter
   ;; 1   2    3       45       6           7   8     9   10  11
   (" (m)?(HR)?([CR]r?)((HCr?)*)([NJ]?[ba]?)(A)?(s*p?)(P)?(S)?(H[CR])? "
    |
    (1 =)
    (2 otf:khmr=pref+)
    (3 = *)
    (4 otf:khmr=blwf,pstf+)
    (6 = *)
    (7 otf:khmr=abvf+)
    (8 = *)
    (9 otf:khmr=pstf+)
    (10 =)
    (11 otf:khmr=blwf,pstf+)
    | )

   ("." =))
  *))

;; Now a syllable looks like below.  ~ characters are OTF feature applied.
;; m?(HR)?[CR](r|c)?(HCr?)*[NJ]?(b|a|A)?s*(p|P)?S?(H[CR])?
;;    ~~   ~~    ~   ~~~~            ~       ~     ~~~~~

;; Step 2.
;; Concatenate adjacent Khmer syllables.
;; Remove J.  Retain N to prevent ligature.

(generator
 (0
  (cond
   ("  ")
   ("J")
   ("." =))
  *))

;; Step 3.
;; Apply other OTF features.

(generator
 (0
  (cond
   (" ([^ ]*) "
    (1 otf:khmr=pres,blws,abvs,psts,clig))
   ("."
    [ otf:sinh=+ ]))
  *))

;; Step 4.
;; Remove N to clean up.
(generator
 (0
  (cond
   ("N")
   ("." =))
  *))

;; Local Variables:
;; mode: emacs-lisp
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