From 36d22d82aa202bb199967e9512281e9a53db42c9 Mon Sep 17 00:00:00 2001
From: Daniel Baumann
+ * "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
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