Soprano::LanguageTag Class Reference

A LanguageTag represents a language according to RFC 3066 and RFC 4646. More...

#include <Soprano/LanguageTag>

List of all members.

Public Types
enum	LookupFlag { LookupFlagNone = 0, LookupFlagNoFallback = 1 }
enum	MatchFilter { MatchFilterBasic = 0, MatchFilterExtended = 1 }
Public Member Functions
Constructors
	LanguageTag (QLocale::Language lang, QLocale::Country country=QLocale::AnyCountry)
	LanguageTag (const QLocale &locale)
	LanguageTag (const QString &tag)
	LanguageTag (const QLatin1String &tag)
	LanguageTag (const char *tag)
	LanguageTag (const LanguageTag &other)
	LanguageTag ()
	~LanguageTag ()
Information
bool	isEmpty () const
bool	isValid () const
QStringList	subTags () const
Operators
bool	matches (const LanguageTag &range, MatchFilter scheme=MatchFilterBasic) const
bool	operator!= (const LanguageTag &other) const
bool	operator< (const LanguageTag &other) const
bool	operator<= (const LanguageTag &other) const
LanguageTag &	operator= (const LanguageTag &other)
bool	operator== (const LanguageTag &other) const
bool	operator> (const LanguageTag &other) const
bool	operator>= (const LanguageTag &other) const
Conversion
	operator QString () const
QLocale	toLocale () const
QString	toPrettyString () const
QString	toString () const
Static Public Member Functions
static int	lookup (const QList< LanguageTag > &choices, const LanguageTag &priority, LookupFlags flags=LookupFlagNone, MatchFilter scheme=MatchFilterBasic)
static int	lookup (const QList< LanguageTag > &choices, const QList< LanguageTag > &priority, LookupFlags flags=LookupFlagNone, MatchFilter scheme=MatchFilterBasic)

---

Detailed Description

A LanguageTag represents a language according to RFC 3066 and RFC 4646.

Author:

Greg Beauchesne <greg_b@vision-play.com>

Since:

2.3

Definition at line 44 of file languagetag.h.

---

Member Enumeration Documentation

enum Soprano::LanguageTag::LookupFlag

Flags for performing LanguageTag lookups.

See also:

lookup()

Enumerator:

LookupFlagNone
LookupFlagNoFallback	Disables fallback behavior for lookup ranges.

Definition at line 70 of file languagetag.h.

enum Soprano::LanguageTag::MatchFilter

Enumerator:

MatchFilterBasic	Represents basic language filtering as described in RFC 3066 section 2.5 (or RFC 4647 section 3.3.1). Basic language filtering checks only that the range string is a prefix of a language tag and that the prefix is followed by "-" or the end of the string. Additionally, the language range "*" matches all tags.
MatchFilterExtended	Represents extended language filtering as described in RFC 4647 section 3.3.2. Extended language filtering breaks tags up into subtags and is permitted to skip subtags in the language tag in order to match parts of the range string.

Definition at line 47 of file languagetag.h.

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Constructor & Destructor Documentation

Soprano::LanguageTag::LanguageTag

(

)

Default constructor.

Creates an empty language tag.

Soprano::LanguageTag::LanguageTag

(

const LanguageTag &

other

)

Copy constructor.

Parameters:

other

The language tag from which to copy

Soprano::LanguageTag::LanguageTag

(

const char *

tag

)

Creates a language tag.

Parameters:

tag

The language tag string

Soprano::LanguageTag::LanguageTag

(

const QLatin1String &

tag

)

Creates a language tag.

Parameters:

tag

The language tag string

Soprano::LanguageTag::LanguageTag

(

const QString &

tag

)

Creates a language tag.

Parameters:

tag

The language tag string

Soprano::LanguageTag::LanguageTag

(

const QLocale &

locale

)

[explicit]

Creates a language tag from a QLocale.

If the language is QLocale::C, then an empty LanguageTag is produced.

Parameters:

locale

the locale

Soprano::LanguageTag::LanguageTag	(	QLocale::Language	lang,
		QLocale::Country	country = QLocale::AnyCountry
	)

Creates a language tag from a language and country.

If lang is QLocale::C, then an empty LanguageTag is produced.

Parameters:

	lang	the language code
	country	the country code

Soprano::LanguageTag::~LanguageTag

(

)

Destructor.

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Member Function Documentation

bool Soprano::LanguageTag::isEmpty

(

)

const

Returns:

true if this language tag is empty.

bool Soprano::LanguageTag::isValid

(

)

const

Determines if this language tag is valid.

A valid language tag is divided into subtags that are divided by "-". The tag must adhere the following rules:

• Each subtag is composed only of characters in the ASCII range [a-zA-Z0-9] (letters and digits), with the exception of the first subtag, which must be composed of letters only
• No subtags are empty
• No subtags are longer than 8 characters
• Single-character subtags cannot end the tag unless after a private use ("x") subtag (e.g. "en-x-i" and "en-x-abcd-i" are legal; "en-x", "en-i", and "en-i-abcd-g" are illegal)

Returns:

true if this language tag is valid

static int Soprano::LanguageTag::lookup	(	const QList< LanguageTag > &	choices,
		const LanguageTag &	priority,
		LookupFlags	flags = LookupFlagNone,
		MatchFilter	scheme = MatchFilterBasic
	)			[static]

A convenience method to select a language tag based on a single search pattern.

Parameters:

	choices	the list of available language choices
	priority	the language range against which to match
	flags	flags for the lookup operation
	scheme	the matching scheme to use. RFC 4647 specifies that basic (MatchFilterBasic) processing should be used.

Returns:

the index of the matching language tag in choices, or < 0 if no tag matched.

See also:

lookup(const QList<LanguageTag> &, const QList<LanguageTag> &, LookupFlags, MatchFilter)

static int Soprano::LanguageTag::lookup	(	const QList< LanguageTag > &	choices,
		const QList< LanguageTag > &	priority,
		LookupFlags	flags = LookupFlagNone,
		MatchFilter	scheme = MatchFilterBasic
	)			[static]

Compares a language tag against a list of language tags and selects the most suitable tag according to the rules of RFC 4647 Section 3.4.

The arguments consist of choices, a list of tags from which to select, and priority, a list of acceptable language ranges. Both lists must be sorted in descending order of preference.

The matching algorithm works as follows:

1. For each item in the priority list, the choices list is scanned for matches. The wildcard value "*" is ignored in lookup operations, as it would match any tag. If a match occurs, the lookup is complete and the matching choices list index is returned.
2. If no match has been found, the last subtag on the current priority item is truncated, and the choices list is scanned again. Single-character subtags are also truncated if they are at the end of the tag. This repeats until there are no subtags remaining. This fallback behavior can be skipped by specifying the LookupFlagsNoFallback flag.
3. If neither the current priority item nor any of its fallback values matched the choices list, then the next item in the priority list is considered according to the above steps.
4. If none of the priority items match the choices list, then a value < 0 is returned.

Parameters:

	choices	the list of available language choices
	priority	the language priority list
	flags	flags for the lookup operation
	scheme	the matching scheme to use. RFC 4647 specifies that basic (MatchFilterBasic) processing should be used.

Returns:

the index of the matching language tag in choices, or < 0 if no tag matched.

bool Soprano::LanguageTag::matches	(	const LanguageTag &	range,
		MatchFilter	scheme = MatchFilterBasic
	)			const

Match this language tag against range using the specified filtering scheme.

Parameters:

	range	the range against which to match
	scheme	the filtering scheme to use

Returns:

true if this tag matches pattern, false if not.

Soprano::LanguageTag::operator QString

(

)

const [inline]

A convenience operator to convert this LanguageTag to a string.

Returns:

the string representation of this LanguageTag

See also:

toString()

Definition at line 277 of file languagetag.h.

bool Soprano::LanguageTag::operator!=

(

const LanguageTag &

other

)

const

Comparison operator.

Language tag comparisons are case-insensitive.

Returns:

true if this tag and other differ.

bool Soprano::LanguageTag::operator<

(

const LanguageTag &

other

)

const

Comparison operator.

Returns:

true if this tag is lexically less than other.

bool Soprano::LanguageTag::operator<=

(

const LanguageTag &

other

)

const

Comparison operator.

Returns:

true if this tag is lexically less than or equal to other.

LanguageTag& Soprano::LanguageTag::operator=

(

const LanguageTag &

other

)

Assigns other to this tag.

bool Soprano::LanguageTag::operator==

(

const LanguageTag &

other

)

const

Comparison operator.

Language tag comparisons are case-insensitive.

Returns:

true if this tag and other are equal.

bool Soprano::LanguageTag::operator>

(

const LanguageTag &

other

)

const

Comparison operator.

Returns:

true if this tag is lexically greater than other.

bool Soprano::LanguageTag::operator>=

(

const LanguageTag &

other

)

const

Comparison operator.

Returns:

true if this tag is lexically greater than or equal to other.

QStringList Soprano::LanguageTag::subTags

(

)

const

Returns:

the subtag parts that make up this language tag

QLocale Soprano::LanguageTag::toLocale

(

)

const

Converts this LanguageTag to a locale, using the primary language tag and first two-letter language subtag, if any.

If the conversion could not be performed, then the "C" QLocale is returned.

Returns:

the converted locale

Note:

QLocale restricts the countries that can be paired with a particular language. If the language-country pair in this tag is not in the QLocale database, or if this language tag does not contain country information, then the most appropriate country will be used for the locale. For example, "de-US" (German as spoken in the United States) is not a valid combination, and the country would be changed to Germany.

QString Soprano::LanguageTag::toPrettyString

(

)

const

Converts this LanguageTag to a string formatted according to the case rules in RFC 4647 section 4.4 (page 44).

Returns:

the pretty string representation of this LanguageTag

QString Soprano::LanguageTag::toString

(

)

const

Converts this LanguageTag to a string.

Returns:

the string representation of this LanguageTag

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The documentation for this class was generated from the following file:

• languagetag.h