1valtype::luhn(n) Validation types valtype::luhn(n)
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8 valtype::luhn - Validation for plain number with a LUHN checkdigit
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11 package require Tcl 8.5
12 package require snit 2
14 package require valtype::common
16 package require valtype::luhn ?1?
18 valtype::luhn validate value
20 valtype::luhn checkdigit value
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26 This package implements a snit validation type for a plain number with
27 a LUHN checkdigit.
28 A validation type is an object that can be used to validate Tcl values
30 of a particular kind. For example, snit::integer, a validation type
31 defined by the snit package is used to validate that a Tcl value is an
32 integer.
33 Every validation type has a validate method which is used to do the
35 validation. This method must take a single argument, the value to be
36 validated; further, it must do nothing if the value is valid, but throw
37 an error if the value is invalid:
38 valtype::luhn validate .... ;# Does nothing
41 valtype::luhn validate .... ;# Throws an error (bad luhn checkdigit).
42 The validate method will always return the validated value on success,
45 and throw the -errorcode INVALID on error, possibly with additional el‐
46 ements which provide more details about the problem.
47
49 The API provided by this package satisfies the specification of snit
50 validation types found in the documentation of Snit's Not Incr Tcl.
51 valtype::luhn validate value
53 This method validates the value and returns it, possibly in a
54 canonical form, if it passes. If the value does not pass the
55 validation an error is thrown.
56 valtype::luhn checkdigit value
58 This method computes a check digit for the value. Before doing
59 so it is validated, except for a checkdigit. If the value does
60 not pass the validation no check digit is calculated and an er‐
61 ror is thrown instead.
62
64 As said in the package description, the errors thrown by the commands
65 of this package in response to input validation failures use the -er‐
66 rorcode INVALID to distinguish themselves from package internal errors.
67 To provide more detailed information about why the validation failed
69 the -errorCode goes actually beyond that. First, it will contain a
70 code detailing the type itself. Here this is LUHN. This is then fol‐
71 lowed by values detailing the reason for the failure. The full set of
72 -errorCodes which can be thrown by this package are:
73 INVALID LUHN CHARACTER
75 The input value contained one or more bad characters, i.e. char‐
76 acters which must not occur in the input for it to be a plain
77 number with a LUHN checkdigit.
78 INVALID LUHN CHECK-DIGIT
80 The check digit of the input value is wrong. This usually sig‐
81 nals a data-entry error, with digits transposed, forgotten, etc.
82 Of course, th input may be an outright fake too.
83
85 This document, and the package it describes, will undoubtedly contain
86 bugs and other problems. Please report such in the category valtype of
87 the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please
88 also report any ideas for enhancements you may have for either package
89 and/or documentation.
90 When proposing code changes, please provide unified diffs, i.e the out‐
92 put of diff -u.
93 Note further that attachments are strongly preferred over inlined
95 patches. Attachments can be made by going to the Edit form of the
96 ticket immediately after its creation, and then using the left-most
97 button in the secondary navigation bar.
98
100 Checking, Testing, Type checking, Validation, Value checking, isA, luhn
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103 Validation, Type checking
104
106 Copyright (c) 2011 Andreas Kupries <andreas_kupries@users.sourceforge.net>
107tcllib 1 valtype::luhn(n)