collapseos/blk/110

: _F ( F without _type and _pln. used in VE )
    FBUF EDPOS @ _cpos 1+ ( a1 a2 )
    BEGIN
        C@+ ROT ( a2+1 c2 a1 ) C@+ ROT ( a2+1 a1+1 c1 c2 )
        = NOT IF DROP FBUF THEN ( a2 a1 )
        TUCK C@ 0xd = ( a1 a2 f1 )
        OVER BLK) = OR ( a1 a2 f1|f2 )
    UNTIL ( a1 a2 )
    DUP BLK) < IF BLK( - FBUF + -^ EDPOS ! ELSE DROP THEN ;
: F FBUF _type _F EDPOS @ 64 / _pln ;