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# valtype::common(n) 1 tcllib "Validation types"

## Name

valtype::common - Validation, common code

## Synopsis

- package require Tcl 8.5
- package require valtype::common ?1?

- valtype::common::reject code text
- valtype::common::badchar code ?text?
- valtype::common::badcheck code ?text?
- valtype::common::badlength code lengths ?text?
- valtype::common::badprefix code prefixes ?text?

## Description

This package implements a number of common commands used by the validation types in this module. These commands essentially encapsulate the throwing of validation errors, ensuring that a proper -errorcode is used. See section Error Codes.

## API

valtype::common::reject code text

  The core command of this package it throws an INVALID error with the specified text. The first argument is a list of codes extending the INVALID with detail information.

valtype::common::badchar code ?text?

  This command throws an INVALID CHAR error with the specified text. The first argument is a list of codes providing details. These are inserted between the codes INVALID and CHARACTER.

valtype::common::badcheck code ?text?

  This command throws an INVALID CHECK-DIGIT error with the specified text, if any, extended by the standard text "the check digit is incorrect". The first argument is a list of codes providing details. These are inserted between the codes INVALID and CHECK_DIGIT.

valtype::common::badlength code lengths ?text?

  This command throws an INVALID LENGTH error with the specified text, if any, extended by the standard text "incorrect length, expected ... character(s)". The first argument is a list of codes providing details. These are inserted between the codes INVALID and LENGTH. The argument lengths is a list of the input lengths which had been expected, i.e. these are the valid lengths.

valtype::common::badprefix code prefixes ?text?

  This command throws an INVALID PREFIX error with the specified text, if any, extended by the standard text "incorrect prefix, expected ...". The first argument is a list of codes providing details. These are inserted between the codes INVALID and PREFIX. The argument prefixes is a list of the input prefixes which had been expected, i.e. these are the valid prefixes.

## Error Codes

The errors thrown by the commands of this package all use the -errorcode INVALID to distinguish the input validation failures they represent 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. This is supplied by the caller. 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 shown below, with <> a placeholder for both the caller-supplied type-information, the type description.

INVALID <> 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 <>.

INVALID <> 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 <> LENGTH

  The input value is of the wrong length to be a <>.

INVALID <> PREFIX

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

## 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. 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, Testing, Type checking, Validation, Value checking, isA

## Category

Validation, Type checking

## Copyright

Copyright © 2011 Andreas Kupries <andreas_kupries@users.sourceforge.net>