---
name: "cc_mastercard"
section: "3tcl"
platform: "linux"
package: "tcllib"
version: "2.0+dfsg-4"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/cc_mastercard"
---

# cc\_mastercard(3tcl)

Validation for Mastercard creditcard number

```

```

## NAME

valtype::creditcard::mastercard - Validation for Mastercard creditcard number

## SYNOPSIS

package require **Tcl 8.5 9**

package require **snit 2**

package require **valtype::common**

package require **valtype::luhn**

package require **valtype::creditcard::mastercard ?1.1?**

**valtype::creditcard::mastercard** **validate** *value*

**valtype::creditcard::mastercard** **checkdigit** *value*

```

```

## DESCRIPTION

This package implements a snit validation type for a Mastercard 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::mastercard validate .... ;# Does nothing
    valtype::creditcard::mastercard validate .... ;# Throws an error (bad Mastercard 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::mastercard** **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::mastercard** **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 MASTERCARD**. This is then followed by values detailing the reason for the failure. The full set of **-errorCode**s which can be thrown by this package are:

- INVALID CREDITCARD MASTERCARD 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 Mastercard creditcard number.

- INVALID CREDITCARD MASTERCARD 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 MASTERCARD LENGTH

  The input value is of the wrong length to be a Mastercard creditcard number.

- INVALID CREDITCARD MASTERCARD PREFIX

  The input value does not start with the magic value(s) required for it to be a Mastercard 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 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.

## KEYWORDS

Checking, MasterCard, 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>
```