 GENERIC: begin-cursor ( collection -- cursor )
 GENERIC: end-cursor ( collection -- cursor )
 
+: all ( collection -- begin end )
+    [ begin-cursor ] [ end-cursor ] bi ; inline
+
 : all- ( collection quot -- begin end quot )
-    [ [ begin-cursor ] [ end-cursor ] bi ] dip ; inline
+    [ all ] dip ; inline
 
 !
 ! containers

    [ n>> ] [ hashtable>> array>> ] bi
    [ nth-unsafe ] [ [ 1 + ] dip nth-unsafe ] 2bi ; inline

INSTANCE: hashtable collection

M: hashtable begin-cursor
    dup array>> 0 (inc-hashtable-cursor) <hashtable-cursor> ; inline

M: output-cursor set-cursor-value-unsafe set-cursor-value ; inline
M: output-cursor set-cursor-value
    dup cursor-valid? [ set-cursor-value-unsafe ] [ invalid-cursor ] if ; inline

!
! stream cursors
!

MIXIN: stream-cursor
INSTANCE: stream-cursor forward-cursor

M: stream-cursor cursor-compatible? 2drop f ; inline
M: stream-cursor cursor-valid? drop t ; inline
M: stream-cursor cursor= 2drop f ; inline

MIXIN: infinite-stream-cursor
INSTANCE: infinite-stream-cursor stream-cursor

M: infinite-stream-cursor inc-cursor ; inline

MIXIN: finite-stream-cursor
INSTANCE: finite-stream-cursor stream-cursor

SINGLETON: end-of-stream

GENERIC: cursor-stream-ended? ( cursor -- ? )

M: finite-stream-cursor inc-cursor
    dup cursor-stream-ended? [ drop end-of-stream ] when ; inline

INSTANCE: end-of-stream finite-stream-cursor

M: end-of-stream cursor-compatible? drop finite-stream-cursor? ; inline
M: end-of-stream cursor-valid? drop f ; inline
M: end-of-stream cursor= eq? ; inline
M: end-of-stream inc-cursor ; inline
M: end-of-stream cursor-stream-ended? drop t ; inline

!
! basic iterator
