@scan(f:function, t:tab)
returns the tab of the partial reduction by f of the elements of t: 
       [ t[0], f(t[0],t[1]), f(f(t[0], t[1]),t[2]), ...]
For example, the tab of the partial sums of the integers between 0 (included) and 10 (excluded) is computed by the expression: 
       @scan(@+, [$x | $x in (10)])  -> [0,1,3,6,10,15,21,28,36,45]

If t is empty, the results in undef.

See also @reduce and @map.

See also Tab Manipulations @binary_search    @car    @cdr    @clear    [@clone]    @concat    @cons    @copy    @count    @dim    @domain    @drop    @empty    @find    @flatten    @gnuplot    @insert    @iota    @is_list    @is_prefix    @is_subsequence    @is_suffix    @lace    @last    @listify    @map    @max_val    @median    @member    @normalize    @occurs    @parse    @permute    @push_back    @push_front    @range    @reduce    @remove    @remove_duplicate    @replace    @reshape    @resize    @reverse    @rotate    @scan    @scramble    @size    @slice    @sort    @sputter    @stutter    @succession    @tab_history    @tab_history_date    @tab_history_rdate    @take    @to_num