: nth3-unsafe ( n seq -- a b c )
[ nth2-unsafe ] [ [ 2 + ] dip nth-unsafe ] 2bi ; inline
-: (binary-reduce) ( ... seq start quot: ( ... elt1 elt2 -- ... newelt ) from to -- ... value )
+: (binary-reduce) ( ... seq start quot: ( ... elt1 elt2 -- ... newelt ) from length -- ... value )
#! We can't use case here since combinators depends on
#! sequences
- 2dup swap - dup 4 < [
- nip integer>fixnum {
+ dup 4 < [
+ integer>fixnum {
[ 2drop nip ]
[ 2nip swap nth-unsafe ]
[ -rot [ drop swap nth2-unsafe ] dip call ]
[ -rot [ drop swap nth3-unsafe ] dip bi@ ]
} dispatch
] [
- 2/ over [ - dup ] dip
+ [ 2/ ] [ over - ] bi [ 2dup + ] dip
[ (binary-reduce) ] [ 2curry ] curry 2bi@
pick [ 3bi ] dip call
] if ; inline recursive