* "one: n is 1; few: n in 2..4"* This defines two rules, for 'one' and 'few'. The condition for * 'one' is "n is 1" which means that the number must be equal to * 1 for this condition to pass. The condition for 'few' is * "n in 2..4" which means that the number must be between 2 and * 4 inclusive for this condition to pass. All other numbers * are assigned the keyword "other" by the default rule. *
* "zero: n is 0; one: n is 1; zero: n mod 100 in 1..19"* This illustrates that the same keyword can be defined multiple times. * Each rule is examined in order, and the first keyword whose condition * passes is the one returned. Also notes that a modulus is applied * to n in the last rule. Thus its condition holds for 119, 219, 319... *
* "one: n is 1; few: n mod 10 in 2..4 and n mod 100 not in 12..14"* This illustrates conjunction and negation. The condition for 'few' * has two parts, both of which must be met: "n mod 10 in 2..4" and * "n mod 100 not in 12..14". The first part applies a modulus to n * before the test as in the previous example. The second part applies * a different modulus and also uses negation, thus it matches all * numbers _not_ in 12, 13, 14, 112, 113, 114, 212, 213, 214... * *
* Syntax:
* \code
* rules = rule (';' rule)*
* rule = keyword ':' condition
* keyword =
* condition = and_condition ('or' and_condition)*
* and_condition = relation ('and' relation)*
* relation = is_relation | in_relation | within_relation | 'n'
* is_relation = expr 'is' ('not')? value
* in_relation = expr ('not')? 'in' range
* within_relation = expr ('not')? 'within' range
* expr = 'n' ('mod' value)?
* value = digit+
* digit = 0|1|2|3|4|5|6|7|8|9
* range = value'..'value
* \endcode
*
* * The difference between 'in' and 'within' is that 'in' only includes * integers in the specified range, while 'within' includes all values.
** Keywords * could be defined by users or from ICU locale data. There are 6 * predefined values in ICU - 'zero', 'one', 'two', 'few', 'many' and * 'other'. Callers need to check the value of keyword returned by * {@link #select} method. *
* * Examples:
* UnicodeString keyword = pl->select(number);
* if (keyword== UnicodeString("one") {
* ...
* }
* else if ( ... )
*
* Note:* ICU defines plural rules for many locales based on CLDR Language Plural Rules. * For these predefined rules, see CLDR page at * http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html *
*/ class U_I18N_API PluralRules : public UObject { public: /** * Constructor. * @param status Output param set to success/failure code on exit, which * must not indicate a failure before the function call. * * @stable ICU 4.0 */ PluralRules(UErrorCode& status); /** * Copy constructor. * @stable ICU 4.0 */ PluralRules(const PluralRules& other); /** * Destructor. * @stable ICU 4.0 */ virtual ~PluralRules(); /** * Clone * @stable ICU 4.0 */ PluralRules* clone() const; /** * Assignment operator. * @stable ICU 4.0 */ PluralRules& operator=(const PluralRules&); /** * Creates a PluralRules from a description if it is parsable, otherwise * returns null. * * @param description rule description * @param status Output param set to success/failure code on exit, which * must not indicate a failure before the function call. * @return new PluralRules pointer. NULL if there is an error. * @stable ICU 4.0 */ static PluralRules* U_EXPORT2 createRules(const UnicodeString& description, UErrorCode& status); /** * The default rules that accept any number. * * @param status Output param set to success/failure code on exit, which * must not indicate a failure before the function call. * @return new PluralRules pointer. NULL if there is an error. * @stable ICU 4.0 */ static PluralRules* U_EXPORT2 createDefaultRules(UErrorCode& status); /** * Provides access to the predefinedPluralRules for a given
* locale.
*
* @param locale The locale for which a PluralRules object is
* returned.
* @param status Output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @return The predefined PluralRules object pointer for
* this locale. If there's no predefined rules for this locale,
* the rules for the closest parent in the locale hierarchy
* that has one will be returned. The final fallback always
* returns the default 'other' rules.
* @stable ICU 4.0
*/
static PluralRules* U_EXPORT2 forLocale(const Locale& locale, UErrorCode& status);
/**
* Given a number, returns the keyword of the first rule that applies to
* the number. This function can be used with isKeyword* functions to
* determine the keyword for default plural rules.
*
* @param number The number for which the rule has to be determined.
* @return The keyword of the selected rule.
* @stable ICU 4.0
*/
UnicodeString select(int32_t number) const;
/**
* Given a number, returns the keyword of the first rule that applies to
* the number. This function can be used with isKeyword* functions to
* determine the keyword for default plural rules.
*
* @param number The number for which the rule has to be determined.
* @return The keyword of the selected rule.
* @stable ICU 4.0
*/
UnicodeString select(double number) const;
/**
* Returns a list of all rule keywords used in this PluralRules
* object. The rule 'other' is always present by default.
*
* @param status Output param set to success/failure code on exit, which
* must not indicate a failure before the function call.
* @return StringEnumeration with the keywords.
* The caller must delete the object.
* @stable ICU 4.0
*/
StringEnumeration* getKeywords(UErrorCode& status) const;
/**
* Returns TRUE if the given keyword is defined in this
* PluralRules object.
*
* @param keyword the input keyword.
* @return TRUE if the input keyword is defined.
* Otherwise, return FALSE.
* @stable ICU 4.0
*/
UBool isKeyword(const UnicodeString& keyword) const;
/**
* Returns keyword for default plural form.
*
* @return keyword for default plural form.
* @internal 4.0
* @stable ICU 4.0
*/
UnicodeString getKeywordOther() const;
/**
* Compares the equality of two PluralRules objects.
*
* @param other The other PluralRules object to be compared with.
* @return True if the given PluralRules is the same as this
* PluralRules; false otherwise.
* @stable ICU 4.0
*/
virtual UBool operator==(const PluralRules& other) const;
/**
* Compares the inequality of two PluralRules objects.
*
* @param other The PluralRules object to be compared with.
* @return True if the given PluralRules is not the same as this
* PluralRules; false otherwise.
* @stable ICU 4.0
*/
UBool operator!=(const PluralRules& other) const {return !operator==(other);}
/**
* ICU "poor man's RTTI", returns a UClassID for this class.
*
* @stable ICU 4.0
*
*/
static UClassID U_EXPORT2 getStaticClassID(void);
/**
* ICU "poor man's RTTI", returns a UClassID for the actual class.
*
* @stable ICU 4.0
*/
virtual UClassID getDynamicClassID() const;
private:
Hashtable *fLocaleStringsHash;
UnicodeString mLocaleName;
RuleChain *mRules;
RuleParser *mParser;
PluralRules(); // default constructor not implemented
int32_t getRepeatLimit() const;
void parseDescription(UnicodeString& ruleData, RuleChain& rules, UErrorCode &status);
void getNextLocale(const UnicodeString& localeData, int32_t* curIndex, UnicodeString& localeName);
void addRules(RuleChain& rules);
int32_t getNumberValue(const UnicodeString& token) const;
UnicodeString getRuleFromResource(const Locale& locale, UErrorCode& status);
};
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif // _PLURRULE
//eof