(look-and-say) ( str -- )

Vocabulary

rosetta-code.look-and-say

Inputs

str

an object

Outputs

None

Definition

USING: kernel make math math.parser sequences ;

IN: rosetta-code.look-and-say

: (look-and-say) ( str -- )
    unclip-slice swap [ 1 ] 2dip [
        2dup =
        [ drop [ 1 + ] dip ]
        [ [ [ number>string % ] dip , 1 ] dip ] if
    ] each [ number>string % ] [ , ] bi* ;