v-credit-card ( str -- n )
Form validators

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Vocabulary
validators

Inputs

str

a string

Outputs

n	an integer

Word description
If the credit card number passes the Luhn algorithm, converts it to an integer, otherwise throws an error.

Notes
See http://en.wikipedia.org/wiki/Luhn_algorithm for a description of this algorithm.

Definition

USING: kernel math.parser ranges sequences sets ;

IN: validators

: v-credit-card ( str -- n )
    "- " without dup 48 57 [a..b] diff empty? [
        13 v-min-length 16 v-max-length dup luhn?
        [ string>number ] [ "card number check failed" throw ]
        if
    ] [ "invalid credit card number format" throw ] if ;