1valtype::verhoeff(n) Validation types valtype::verhoeff(n)
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6
8 valtype::verhoeff - Validation for plain number with a VERHOEFF check‐
9 digit
10
12 package require Tcl 8.5
13 package require snit 2
15 package require valtype::common
17 package require valtype::verhoeff ?1?
19 valtype::verhoeff validate value
21 valtype::verhoeff checkdigit value
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25
27 This package implements a snit validation type for a plain number with
28 a VERHOEFF checkdigit.
29 A validation type is an object that can be used to validate Tcl values
31 of a particular kind. For example, snit::integer, a validation type
32 defined by the snit package is used to validate that a Tcl value is an
33 integer.
34 Every validation type has a validate method which is used to do the
36 validation. This method must take a single argument, the value to be
37 validated; further, it must do nothing if the value is valid, but throw
38 an error if the value is invalid:
39 valtype::verhoeff validate .... ;# Does nothing
42 valtype::verhoeff validate .... ;# Throws an error (bad verhoeff checkdigit).
43 The validate method will always return the validated value on success,
46 and throw the -errorcode INVALID on error, possibly with additional el‐
47 ements which provide more details about the problem.
48
50 The API provided by this package satisfies the specification of snit
51 validation types found in the documentation of Snit's Not Incr Tcl.
52 valtype::verhoeff validate value
54 This method validates the value and returns it, possibly in a
55 canonical form, if it passes. If the value does not pass the
56 validation an error is thrown.
57 valtype::verhoeff checkdigit value
59 This method computes a check digit for the value. Before doing
60 so it is validated, except for a checkdigit. If the value does
61 not pass the validation no check digit is calculated and an er‐
62 ror is thrown instead.
63
65 As said in the package description, the errors thrown by the commands
66 of this package in response to input validation failures use the -er‐
67 rorcode INVALID to distinguish themselves from package internal errors.
68 To provide more detailed information about why the validation failed
70 the -errorCode goes actually beyond that. First, it will contain a
71 code detailing the type itself. Here this is VERHOEFF. This is then
72 followed by values detailing the reason for the failure. The full set
73 of -errorCodes which can be thrown by this package are:
74 INVALID VERHOEFF CHARACTER
76 The input value contained one or more bad characters, i.e. char‐
77 acters which must not occur in the input for it to be a plain
78 number with a VERHOEFF checkdigit.
79 INVALID VERHOEFF CHECK-DIGIT
81 The check digit of the input value is wrong. This usually sig‐
82 nals a data-entry error, with digits transposed, forgotten, etc.
83 Of course, th input may be an outright fake too.
84
86 This document, and the package it describes, will undoubtedly contain
87 bugs and other problems. Please report such in the category valtype of
88 the Tcllib Trackers [http://core.tcl.tk/tcllib/reportlist]. Please
89 also report any ideas for enhancements you may have for either package
90 and/or documentation.
91 When proposing code changes, please provide unified diffs, i.e the out‐
93 put of diff -u.
94 Note further that attachments are strongly preferred over inlined
96 patches. Attachments can be made by going to the Edit form of the
97 ticket immediately after its creation, and then using the left-most
98 button in the secondary navigation bar.
99
101 Checking, Testing, Type checking, Validation, Value checking, isA, ver‐
102 hoeff
103
105 Validation, Type checking
106
108 Copyright (c) 2011 Andreas Kupries <andreas_kupries@users.sourceforge.net>
109tcllib 1 valtype::verhoeff(n)