NAME¶
valtype::creditcard::discover - Validation for Discover creditcard number
SYNOPSIS¶
package require
Tcl 8.5
package require
snit 2
package require
valtype::common
package require
valtype::luhn
package require
valtype::creditcard::discover ?1?
valtype::creditcard::discover validate value
valtype::creditcard::discover checkdigit value
DESCRIPTION¶
This package implements a snit validation type for a Discover creditcard number.
A validation type is an object that can be used to validate Tcl values of a
particular kind. For example,
snit::integer, a validation type defined
by the
snit package is used to validate that a Tcl value is an integer.
Every validation type has a
validate method which is used to do the
validation. This method must take a single argument, the value to be
validated; further, it must do nothing if the value is valid, but throw an
error if the value is invalid:
valtype::creditcard::discover validate .... ;# Does nothing
valtype::creditcard::discover validate .... ;# Throws an error (bad Discover creditcard number).
The
validate method will always return the validated value on success,
and throw the
-errorcode INVALID on error, possibly with additional
elements which provide more details about the problem.
API¶
The API provided by this package satisfies the specification of snit validation
types found in the documentation of
Snit's Not Incr Tcl.
- valtype::creditcard::discover validate value
- This method validates the value and returns it, possibly in a
canonical form, if it passes. If the value does not pass the validation an
error is thrown.
- valtype::creditcard::discover checkdigit value
- This method computes a check digit for the value. Before doing so
it is validated, except for a checkdigit. If the value does not pass the
validation no check digit is calculated and an error is thrown
instead.
ERROR CODES¶
As said in the package description, the errors thrown by the commands of this
package in response to input validation failures use the
-errorcode
INVALID to distinguish themselves from package internal errors.
To provide more detailed information about why the validation failed the
-errorCode goes actually beyond that. First, it will contain a code
detailing the type itself. Here this is
CREDITCARD DISCOVER. This is
then followed by values detailing the reason for the failure. The full set of
-errorCodes which can be thrown by this package are:
- INVALID CREDITCARD DISCOVER CHARACTER
- The input value contained one or more bad characters, i.e. characters
which must not occur in the input for it to be a Discover creditcard
number.
- INVALID CREDITCARD DISCOVER CHECK-DIGIT
- The check digit of the input value is wrong. This usually signals a
data-entry error, with digits transposed, forgotten, etc. Of course, th
input may be an outright fake too.
- INVALID CREDITCARD DISCOVER LENGTH
- The input value is of the wrong length to be a Discover creditcard
number.
- INVALID CREDITCARD DISCOVER PREFIX
- The input value does not start with the magic value(s) required for it to
be a Discover creditcard number.
BUGS, IDEAS, FEEDBACK¶
This document, and the package it describes, will undoubtedly contain bugs and
other problems. Please report such in the category
valtype of the
Tcllib Trackers [
http://core.tcl.tk/tcllib/reportlist]. Please also
report any ideas for enhancements you may have for either package and/or
documentation.
KEYWORDS¶
Checking, Discover, Testing, Type checking, Validation, Value checking, bank,
card for credit, credit card, finance, isA
CATEGORY¶
Validation, Type checking
COPYRIGHT¶
Copyright (c) 2011 Andreas Kupries <andreas_kupries@users.sourceforge.net>