1valtype::isbn(n)               Validation types               valtype::isbn(n)
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NAME

8       valtype::isbn - Validation for ISBN
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SYNOPSIS

11       package require Tcl  8.5
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13       package require snit  2
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15       package require valtype::common
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17       package require valtype::isbn  ?1?
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19       valtype::isbn validate value
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21       valtype::isbn checkdigit value
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23       valtype::isbn 13of value
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25______________________________________________________________________________
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DESCRIPTION

28       This package implements a snit validation type for an ISBN.
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30       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.
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35       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:
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41                  valtype::isbn validate .... ;# Does nothing
42                  valtype::isbn validate .... ;# Throws an error (bad ISBN).
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45       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.
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API

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.
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53       valtype::isbn 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.
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58       valtype::isbn 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.
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64       valtype::isbn 13of value
65              This  method  expects an old-style 10-digit ISBN and returns the
66              canonical modern 13-digit ISBN.  This is  used  by  validate  to
67              canonicalize  the  input,  so that all parts of the system after
68              the validation can expect to work with modern 13-digit ISBNs.
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ERROR CODES

71       As said in the package description, the errors thrown by  the  commands
72       of  this  package in response to input validation failures use the -er‐
73       rorcode INVALID to distinguish themselves from package internal errors.
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75       To provide more detailed information about why  the  validation  failed
76       the  -errorCode  goes  actually  beyond that.  First, it will contain a
77       code detailing the type itself. Here this is ISBN. This  is  then  fol‐
78       lowed  by  values detailing the reason for the failure. The full set of
79       -errorCodes which can be thrown by this package are:
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81       INVALID ISBN CHARACTER
82              The input value contained one or more bad characters, i.e. char‐
83              acters which must not occur in the input for it to be an ISBN.
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85       INVALID ISBN CHECK-DIGIT
86              The  check  digit of the input value is wrong. This usually sig‐
87              nals a data-entry error, with digits transposed, forgotten, etc.
88              Of course, th input may be an outright fake too.
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90       INVALID ISBN LENGTH
91              The input value is of the wrong length to be an ISBN.
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BUGS, IDEAS, FEEDBACK

94       This  document,  and the package it describes, will undoubtedly contain
95       bugs and other problems.  Please report such in the category valtype of
96       the  Tcllib  Trackers  [http://core.tcl.tk/tcllib/reportlist].   Please
97       also report any ideas for enhancements you may have for either  package
98       and/or documentation.
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100       When proposing code changes, please provide unified diffs, i.e the out‐
101       put of diff -u.
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103       Note further that  attachments  are  strongly  preferred  over  inlined
104       patches.  Attachments  can  be  made  by  going to the Edit form of the
105       ticket immediately after its creation, and  then  using  the  left-most
106       button in the secondary navigation bar.
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KEYWORDS

109       Book  Number,  Checking, EAN, EAN13, European Article Number, ISBN, In‐
110       ternational Article Number, International Standard Book  Number,  Test‐
111       ing, Type checking, Validation, Value checking, isA
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CATEGORY

114       Validation, Type checking
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117       Copyright (c) 2011 Andreas Kupries <andreas_kupries@users.sourceforge.net>
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122tcllib                                 1                      valtype::isbn(n)
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