valtype::creditcard::visa - Validation for VISA creditcard number
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
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
elements which provide more details about the problem.
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 error is
thrown instead.
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 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.
characters 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
signals 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.
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 output
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.
Checking, Testing, Type checking, VISA, Validation, Value checking, bank, card
for credit, credit card, finance, isA
Validation, Type checking
Copyright (c) 2011 Andreas Kupries <[email protected]>