factor/library/collections/vectors-epilogue.factor

! Copyright (C) 2004, 2005 Slava Pestov.
! See http://factor.sf.net/license.txt for BSD license.
USING: errors generic kernel kernel-internals lists math
math-internals sequences ;

IN: vectors

: >vector ( list -- vector ) 0 <vector> [ swap nappend ] keep ;

: vector-project ( n quot -- vector )
    #! Execute the quotation n times, passing the loop counter
    #! the quotation as it ranges from 0..n-1. Collect results
    #! in a new vector.
    project >vector ; inline

: zero-vector ( n -- vector )
    [ drop 0 ] vector-project ;

: vector-tail ( n vector -- list )
    #! Return a new list with all elements from the nth
    #! index upwards.
    2dup length swap - [
        pick + over nth
    ] project 2nip ;

: vector-tail* ( n vector -- list )
    #! Unlike vector-tail, n is an index from the end of the
    #! vector. For example, if n=1, this returns a vector of
    #! one element.
    [ length swap - ] keep vector-tail ;