valtype::creditcard::visa(3tcl)Validation typesvaltype::creditcard::visa(3tcl)
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NAME
valtype::creditcard::visa - Validation for VISA creditcard number
SYNOPSIS
package require Tcl 8.5
package require snit 2
package require valtype::common
package require valtype::luhn
package require valtype::creditcard::visa ?1?
valtype::creditcard::visa validate value
valtype::creditcard::visa checkdigit value
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DESCRIPTION
This package implements a snit validation type for a VISA 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::visa validate .... ;# Does nothing
valtype::creditcard::visa validate .... ;# Throws an error (bad VISA creditcard number).
The validate method will always return the validated value on success,
and throw the -errorcode INVALID on error, possibly with additional el-
ements 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::visa 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::visa 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 er-
ror 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 -er-
rorcode 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 VISA. 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 VISA CHARACTER
The input value contained one or more bad characters, i.e. char-
acters which must not occur in the input for it to be a VISA
creditcard number.
INVALID CREDITCARD VISA CHECK-DIGIT
The check digit of the input value is wrong. This usually sig-
nals a data-entry error, with digits transposed, forgotten, etc.
Of course, th input may be an outright fake too.
INVALID CREDITCARD VISA LENGTH
The input value is of the wrong length to be a VISA creditcard
number.
INVALID CREDITCARD VISA PREFIX
The input value does not start with the magic value(s) required
for it to be a VISA 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.
When proposing code changes, please provide unified diffs, i.e the out-
put of diff -u.
Note further that attachments are strongly preferred over inlined
patches. Attachments can be made by going to the Edit form of the
ticket immediately after its creation, and then using the left-most
button in the secondary navigation bar.
KEYWORDS
Checking, Testing, Type checking, VISA, 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>
tcllib 1 valtype::creditcard::visa(3tcl)