* "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_list
* within_relation = expr ('not')? 'within' range
* expr = ('n' | 'i' | 'f' | 'v' | 'j') ('mod' value)?
* range_list = (range | value) (',' range_list)*
* value = digit+ ('.' digit+)?
* digit = 0|1|2|3|4|5|6|7|8|9
* range = value'..'value
* \endcode
*
* *
* The i, f, and v values are defined as follows: *
** Examples are in the following table: *
*| n | *i | *f | *v | *
|---|---|---|---|
| 1.0 | *1 | *0 | *1 | *
| 1.00 | *1 | *0 | *2 | *
| 1.3 | *1 | *3 | *1 | *
| 1.03 | *1 | *3 | *2 | *
| 1.23 | *1 | *23 | *2 | *
* The difference between 'in' and 'within' is that 'in' only includes integers in the specified range, while 'within' * includes all values. Using 'within' with a range_list consisting entirely of values is the same as using 'in' (it's * not an error). *
* An "identifier" is a sequence of characters that do not have the * Unicode Pattern_Syntax or Pattern_White_Space properties. ** The difference between 'in' and 'within' is that 'in' only includes * integers in the specified range, while 'within' includes all values. * Using 'within' with a range_list consisting entirely of values is the * same as using 'in' (it's not an error). *
** 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 * https://unicode-org.github.io/cldr-staging/charts/latest/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 nullptr. * * @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. nullptr 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. nullptr if there is an error. * @stable ICU 4.0 */ static PluralRules* U_EXPORT2 createDefaultRules(UErrorCode& status); /** * Provides access to the predefined cardinal-numberPluralRules for a given
* locale.
* Same as forLocale(locale, UPLURAL_TYPE_CARDINAL, status).
*
* @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);
/**
* Provides access to the predefined PluralRules for a given
* locale and the plural type.
*
* @param locale The locale for which a PluralRules object is
* returned.
* @param type The plural type (e.g., cardinal or ordinal).
* @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 50
*/
static PluralRules* U_EXPORT2 forLocale(const Locale& locale, UPluralType type, UErrorCode& status);
#ifndef U_HIDE_INTERNAL_API
/**
* Return a StringEnumeration over the locales for which there is plurals data.
* @return a StringEnumeration over the locales available.
* @internal
*/
static StringEnumeration* U_EXPORT2 getAvailableLocales(UErrorCode &status);
/**
* For ICU use only.
* creates a SharedPluralRules object
* @internal
*/
static PluralRules* U_EXPORT2 internalForLocale(const Locale& locale, UPluralType type, UErrorCode& status);
/**
* For ICU use only.
* Returns handle to the shared, cached PluralRules instance.
* Caller must call removeRef() on returned value once it is done with
* the shared instance.
* @internal
*/
static const SharedPluralRules* U_EXPORT2 createSharedInstance(
const Locale& locale, UPluralType type, UErrorCode& status);
#endif /* U_HIDE_INTERNAL_API */
/**
* Given an integer, 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 floating-point 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;
/**
* Given a formatted 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.
*
* A FormattedNumber allows you to specify an exponent or trailing zeros,
* which can affect the plural category. To get a FormattedNumber, see
* NumberFormatter.
*
* @param number The number for which the rule has to be determined.
* @param status Set if an error occurs while selecting plural keyword.
* This could happen if the FormattedNumber is invalid.
* @return The keyword of the selected rule.
* @stable ICU 64
*/
UnicodeString select(const number::FormattedNumber& number, UErrorCode& status) const;
/**
* Given a formatted number range, returns the overall plural form of the
* range. For example, "3-5" returns "other" in English.
*
* To get a FormattedNumberRange, see NumberRangeFormatter.
*
* This method only works if PluralRules was created with a locale. If it was created
* from PluralRules::createRules(), this method sets status code U_UNSUPPORTED_ERROR.
*
* @param range The number range onto which the rules will be applied.
* @param status Set if an error occurs while selecting plural keyword.
* This could happen if the FormattedNumberRange is invalid,
* or if plural ranges data is unavailable.
* @return The keyword of the selected rule.
* @stable ICU 68
*/
UnicodeString select(const number::FormattedNumberRange& range, UErrorCode& status) const;
#ifndef U_HIDE_INTERNAL_API
/**
* @internal
*/
UnicodeString select(const IFixedDecimal &number) const;
/**
* @internal
*/
UnicodeString select(const number::impl::UFormattedNumberRangeData* urange, UErrorCode& status) const;
#endif /* U_HIDE_INTERNAL_API */
/**
* 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;
#ifndef U_HIDE_DEPRECATED_API
/**
* Deprecated Function, does not return useful results.
*
* Originally intended to return a unique value for this keyword if it exists,
* else the constant UPLRULES_NO_UNIQUE_VALUE.
*
* @param keyword The keyword.
* @return Stub deprecated function returns UPLRULES_NO_UNIQUE_VALUE always.
* @deprecated ICU 55
*/
double getUniqueKeywordValue(const UnicodeString& keyword);
/**
* Deprecated Function, does not produce useful results.
*
* Originally intended to return all the values for which select() would return the keyword.
* If the keyword is unknown, returns no values, but this is not an error. If
* the number of values is unlimited, returns no values and -1 as the
* count.
*
* The number of returned values is typically small.
*
* @param keyword The keyword.
* @param dest Array into which to put the returned values. May
* be nullptr if destCapacity is 0.
* @param destCapacity The capacity of the array, must be at least 0.
* @param status The error code. Deprecated function, always sets U_UNSUPPORTED_ERROR.
* @return The count of values available, or -1. This count
* can be larger than destCapacity, but no more than
* destCapacity values will be written.
* @deprecated ICU 55
*/
int32_t getAllKeywordValues(const UnicodeString &keyword,
double *dest, int32_t destCapacity,
UErrorCode& status);
#endif /* U_HIDE_DEPRECATED_API */
/**
* Returns sample values for which select() would return the keyword. If
* the keyword is unknown, returns no values, but this is not an error.
*
* The number of returned values is typically small.
*
* @param keyword The keyword.
* @param dest Array into which to put the returned values. May
* be nullptr if destCapacity is 0.
* @param destCapacity The capacity of the array, must be at least 0.
* @param status The error code.
* @return The count of values written.
* If more than destCapacity samples are available, then
* only destCapacity are written, and destCapacity is returned as the count,
* rather than setting a U_BUFFER_OVERFLOW_ERROR.
* (The actual number of keyword values could be unlimited.)
* @stable ICU 4.8
*/
int32_t getSamples(const UnicodeString &keyword,
double *dest, int32_t destCapacity,
UErrorCode& status);
#ifndef U_HIDE_INTERNAL_API
/**
* Internal-only function that returns DecimalQuantitys instead of doubles.
*
* Returns sample values for which select() would return the keyword. If
* the keyword is unknown, returns no values, but this is not an error.
*
* The number of returned values is typically small.
*
* @param keyword The keyword.
* @param dest Array into which to put the returned values. May
* be nullptr if destCapacity is 0.
* @param destCapacity The capacity of the array, must be at least 0.
* @param status The error code.
* @return The count of values written.
* If more than destCapacity samples are available, then
* only destCapacity are written, and destCapacity is returned as the count,
* rather than setting a U_BUFFER_OVERFLOW_ERROR.
* (The actual number of keyword values could be unlimited.)
* @internal
*/
int32_t getSamples(const UnicodeString &keyword,
DecimalQuantity *dest, int32_t destCapacity,
UErrorCode& status);
#endif /* U_HIDE_INTERNAL_API */
/**
* 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.
* @stable ICU 4.0
*/
UnicodeString getKeywordOther() const;
#ifndef U_HIDE_INTERNAL_API
/**
*
* @internal
*/
UnicodeString getRules() const;
#endif /* U_HIDE_INTERNAL_API */
/**
* 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 bool 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
*/
bool 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 override;
private:
RuleChain *mRules;
StandardPluralRanges *mStandardPluralRanges;
PluralRules() = delete; // default constructor not implemented
UnicodeString getRuleFromResource(const Locale& locale, UPluralType type, UErrorCode& status);
RuleChain *rulesForKeyword(const UnicodeString &keyword) const;
PluralRules *clone(UErrorCode& status) const;
/**
* An internal status variable used to indicate that the object is in an 'invalid' state.
* Used by copy constructor, the assignment operator and the clone method.
*/
UErrorCode mInternalStatus;
friend class PluralRuleParser;
};
U_NAMESPACE_END
#endif /* #if !UCONFIG_NO_FORMATTING */
#endif /* U_SHOW_CPLUSPLUS_API */
#endif // _PLURRULE
//eof