take-n ( sequence-parser n -- seq/f )

Vocabulary

sequences.parser

Inputs

sequence-parser	a sequence-parser
n	an integer

Outputs

seq/f

a sequence or f

Definition

USING: accessors kernel math sequences ;

IN: sequences.parser

:: take-n ( sequence-parser n -- seq/f )
    n sequence-parser [ n>> + ] [ sequence>> length ] bi >
    [ sequence-parser take-rest ] [
        sequence-parser n>> dup n +
        sequence-parser sequence>> subseq sequence-parser
        [ n + ] change-n drop
    ] if ;