ICU 76.1 76.1
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#include <plurfmt.h>
Public Member Functions | |
PluralFormat (UErrorCode &status) | |
Creates a new cardinal-number PluralFormat for the default locale. | |
PluralFormat (const Locale &locale, UErrorCode &status) | |
Creates a new cardinal-number PluralFormat for a given locale. | |
PluralFormat (const PluralRules &rules, UErrorCode &status) | |
Creates a new PluralFormat for a given set of rules. | |
PluralFormat (const Locale &locale, const PluralRules &rules, UErrorCode &status) | |
Creates a new PluralFormat for a given set of rules. | |
PluralFormat (const Locale &locale, UPluralType type, UErrorCode &status) | |
Creates a new PluralFormat for the plural type. | |
PluralFormat (const UnicodeString &pattern, UErrorCode &status) | |
Creates a new cardinal-number PluralFormat for a given pattern string. | |
PluralFormat (const Locale &locale, const UnicodeString &pattern, UErrorCode &status) | |
Creates a new cardinal-number PluralFormat for a given pattern string and locale. | |
PluralFormat (const PluralRules &rules, const UnicodeString &pattern, UErrorCode &status) | |
Creates a new PluralFormat for a given set of rules, a pattern and a locale. | |
PluralFormat (const Locale &locale, const PluralRules &rules, const UnicodeString &pattern, UErrorCode &status) | |
Creates a new PluralFormat for a given set of rules, a pattern and a locale. | |
PluralFormat (const Locale &locale, UPluralType type, const UnicodeString &pattern, UErrorCode &status) | |
Creates a new PluralFormat for a plural type, a pattern and a locale. | |
PluralFormat (const PluralFormat &other) | |
copy constructor. | |
virtual | ~PluralFormat () |
Destructor. | |
void | applyPattern (const UnicodeString &pattern, UErrorCode &status) |
Sets the pattern used by this plural format. | |
UnicodeString | format (int32_t number, UErrorCode &status) const |
Formats a plural message for a given number. | |
UnicodeString | format (double number, UErrorCode &status) const |
Formats a plural message for a given number. | |
UnicodeString & | format (int32_t number, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const |
Formats a plural message for a given number. | |
UnicodeString & | format (double number, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const |
Formats a plural message for a given number. | |
void | setLocale (const Locale &locale, UErrorCode &status) |
Sets the locale used by this PluraFormat object. | |
void | setNumberFormat (const NumberFormat *format, UErrorCode &status) |
Sets the number format used by this formatter. | |
PluralFormat & | operator= (const PluralFormat &other) |
Assignment operator. | |
virtual bool | operator== (const Format &other) const override |
Return true if another object is semantically equal to this one. | |
virtual bool | operator!= (const Format &other) const |
Return true if another object is semantically unequal to this one. | |
virtual PluralFormat * | clone () const override |
Clones this Format object polymorphically. | |
UnicodeString & | format (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const override |
Formats a plural message for a number taken from a Formattable object. | |
UnicodeString & | toPattern (UnicodeString &appendTo) |
Returns the pattern from applyPattern() or constructor(). | |
virtual void | parseObject (const UnicodeString &source, Formattable &result, ParsePosition &parse_pos) const override |
This method is not yet supported by PluralFormat . | |
virtual UClassID | getDynamicClassID () const override |
ICU "poor man's RTTI", returns a UClassID for the actual class. | |
UnicodeString & | format (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const |
Formats an object to produce a string. | |
virtual UnicodeString & | format (const Formattable &obj, UnicodeString &appendTo, FieldPosition &pos, UErrorCode &status) const=0 |
Format an object to produce a string. | |
virtual UnicodeString & | format (const Formattable &obj, UnicodeString &appendTo, FieldPositionIterator *posIter, UErrorCode &status) const |
Format an object to produce a string. | |
Public Member Functions inherited from icu::Format | |
virtual | ~Format () |
Destructor. | |
bool | operator!= (const Format &other) const |
Return true if the given Format objects are not semantically equal. | |
UnicodeString & | format (const Formattable &obj, UnicodeString &appendTo, UErrorCode &status) const |
Formats an object to produce a string. | |
void | parseObject (const UnicodeString &source, Formattable &result, UErrorCode &status) const |
Parses a string to produce an object. | |
Locale | getLocale (ULocDataLocaleType type, UErrorCode &status) const |
Get the locale for this format object. | |
const char * | getLocaleID (ULocDataLocaleType type, UErrorCode &status) const |
Get the locale for this format object. | |
Public Member Functions inherited from icu::UObject | |
virtual | ~UObject () |
Destructor. | |
Static Public Member Functions | |
static UClassID | getStaticClassID () |
ICU "poor man's RTTI", returns a UClassID for this class. | |
Friends | |
class | MessageFormat |
class | NFRule |
Additional Inherited Members | |
Protected Member Functions inherited from icu::Format | |
void | setLocaleIDs (const char *valid, const char *actual) |
Format () | |
Default constructor for subclass use only. | |
Format (const Format &) | |
Format & | operator= (const Format &) |
Static Protected Member Functions inherited from icu::Format | |
static void | syntaxError (const UnicodeString &pattern, int32_t pos, UParseError &parseError) |
Simple function for initializing a UParseError from a UnicodeString. | |
PluralFormat
supports the creation of internationalized messages with plural inflection. It is based on plural selection, i.e. the caller specifies messages for each plural case that can appear in the user's language and the PluralFormat
selects the appropriate message based on the number.
Different languages have different ways to inflect plurals. Creating internationalized messages that include plural forms is only feasible when the framework is able to handle plural forms of all languages correctly. ChoiceFormat
doesn't handle this well, because it attaches a number interval to each message and selects the message whose interval contains a given number. This can only handle a finite number of intervals. But in some languages, like Polish, one plural case applies to infinitely many intervals (e.g., the plural case applies to numbers ending with 2, 3, or 4 except those ending with 12, 13, or 14). Thus ChoiceFormat
is not adequate.
PluralFormat
deals with this by breaking the problem into two parts:
PluralRules
that can define more complex conditions for a plural case than just a single interval. These plural rules define both what plural cases exist in a language, and to which numbers these cases apply. PluralFormat
Note: Typically, plural formatting is done via MessageFormat
with a plural
argument type, rather than using a stand-alone PluralFormat
.
This discussion assumes that you use PluralFormat
with a predefined set of plural rules. You can create one using one of the constructors that takes a locale
object. To specify the message pattern, you can either pass it to the constructor or set it explicitly using the applyPattern()
method. The format()
method takes a number object and selects the message of the matching plural case. This message will be returned.
The pattern text defines the message output for each plural case of the specified locale. Syntax:
pluralStyle = [offsetValue] (selector '{' message '}')+
offsetValue = "offset:" number
selector = explicitValue | keyword
explicitValue = '=' number // adjacent, no white space in between
keyword = [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+
message: see MessageFormat
Pattern_White_Space between syntax elements is ignored, except between the {curly braces} and their sub-message, and between the '=' and the number of an explicitValue.
There are 6 predefined casekeyword in CLDR/ICU - 'zero', 'one', 'two', 'few', 'many' and 'other'. You always have to define a message text for the default plural case other
which is contained in every rule set. If you do not specify a message text for a particular plural case, the message text of the plural case other
gets assigned to this plural case.
When formatting, the input number is first matched against the explicitValue clauses. If there is no exact-number match, then a keyword is selected by calling the PluralRules
with the input number minus the offset. (The offset defaults to 0 if it is omitted from the pattern string.) If there is no clause with that keyword, then the "other" clauses is returned.
An unquoted pound sign (#
) in the selected sub-message itself (i.e., outside of arguments nested in the sub-message) is replaced by the input number minus the offset. The number-minus-offset value is formatted using a NumberFormat
for the PluralFormat
's locale. If you need special number formatting, you have to use a MessageFormat
and explicitly specify a NumberFormat
argument. Note: That argument is formatting without subtracting the offset! If you need a custom format and have a non-zero offset, then you need to pass the number-minus-offset value as a separate parameter.
For a usage example, see the MessageFormat
class documentation.
If you need to use PluralFormat
with custom rules, you can create a PluralRules
object and pass it to PluralFormat
's constructor. If you also specify a locale in this constructor, this locale will be used to format the number in the message texts.
For more information about PluralRules
, see PluralRules
.
ported from Java
icu::PluralFormat::PluralFormat | ( | UErrorCode & | status | ) |
Creates a new cardinal-number PluralFormat
for the default locale.
This locale will be used to get the set of plural rules and for standard number formatting.
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const Locale & | locale, |
UErrorCode & | status | ||
) |
Creates a new cardinal-number PluralFormat
for a given locale.
locale | the PluralFormat will be configured with rules for this locale. This locale will also be used for standard number formatting. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const PluralRules & | rules, |
UErrorCode & | status | ||
) |
Creates a new PluralFormat
for a given set of rules.
The standard number formatting will be done using the default locale.
rules | defines the behavior of the PluralFormat object. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const Locale & | locale, |
const PluralRules & | rules, | ||
UErrorCode & | status | ||
) |
Creates a new PluralFormat
for a given set of rules.
The standard number formatting will be done using the given locale.
locale | the default number formatting will be done using this locale. |
rules | defines the behavior of the PluralFormat object. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const Locale & | locale, |
UPluralType | type, | ||
UErrorCode & | status | ||
) |
Creates a new PluralFormat
for the plural type.
The standard number formatting will be done using the given locale.
locale | the default number formatting will be done using this locale. |
type | The plural type (e.g., cardinal or ordinal). |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const UnicodeString & | pattern, |
UErrorCode & | status | ||
) |
Creates a new cardinal-number PluralFormat
for a given pattern string.
The default locale will be used to get the set of plural rules and for standard number formatting.
pattern | the pattern for this PluralFormat . errors are returned to status if the pattern is invalid. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const Locale & | locale, |
const UnicodeString & | pattern, | ||
UErrorCode & | status | ||
) |
Creates a new cardinal-number PluralFormat
for a given pattern string and locale.
The locale will be used to get the set of plural rules and for standard number formatting.
locale | the PluralFormat will be configured with rules for this locale. This locale will also be used for standard number formatting. |
pattern | the pattern for this PluralFormat . errors are returned to status if the pattern is invalid. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const PluralRules & | rules, |
const UnicodeString & | pattern, | ||
UErrorCode & | status | ||
) |
Creates a new PluralFormat
for a given set of rules, a pattern and a locale.
rules | defines the behavior of the PluralFormat object. |
pattern | the pattern for this PluralFormat . errors are returned to status if the pattern is invalid. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const Locale & | locale, |
const PluralRules & | rules, | ||
const UnicodeString & | pattern, | ||
UErrorCode & | status | ||
) |
Creates a new PluralFormat
for a given set of rules, a pattern and a locale.
locale | the PluralFormat will be configured with rules for this locale. This locale will also be used for standard number formatting. |
rules | defines the behavior of the PluralFormat object. |
pattern | the pattern for this PluralFormat . errors are returned to status if the pattern is invalid. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const Locale & | locale, |
UPluralType | type, | ||
const UnicodeString & | pattern, | ||
UErrorCode & | status | ||
) |
Creates a new PluralFormat
for a plural type, a pattern and a locale.
locale | the PluralFormat will be configured with rules for this locale. This locale will also be used for standard number formatting. |
type | The plural type (e.g., cardinal or ordinal). |
pattern | the pattern for this PluralFormat . errors are returned to status if the pattern is invalid. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
icu::PluralFormat::PluralFormat | ( | const PluralFormat & | other | ) |
copy constructor.
void icu::PluralFormat::applyPattern | ( | const UnicodeString & | pattern, |
UErrorCode & | status | ||
) |
Sets the pattern used by this plural format.
The method parses the pattern and creates a map of format strings for the plural rules. Patterns and their interpretation are specified in the class description.
pattern | the pattern for this plural format errors are returned to status if the pattern is invalid. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
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overridevirtual |
Clones this Format object polymorphically.
The caller owns the result and should delete it when done.
Implements icu::Format.
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overridevirtual |
Formats a plural message for a number taken from a Formattable object.
obj | The object containing a number for which the plural message should be formatted. The object must be of a numeric type. |
appendTo | output parameter to receive result. Result is appended to existing contents. |
pos | On input: an alignment field, if desired. On output: the offsets of the alignment field. |
status | output param filled with success/failure status. |
Implements icu::Format.
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virtual |
Format an object to produce a string.
This is a pure virtual method which subclasses must implement. This method allows polymorphic formatting of Formattable objects. If a subclass of Format receives a Formattable object type it doesn't handle (e.g., if a numeric Formattable is passed to a DateFormat object) then it returns a failing UErrorCode.
obj | The object to format. |
appendTo | Output parameter to receive result. Result is appended to existing contents. |
pos | On input: an alignment field, if desired. On output: the offsets of the alignment field. |
status | Output param filled with success/failure status. |
Implements icu::Format.
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virtual |
Format an object to produce a string.
Subclasses should override this method. This method allows polymorphic formatting of Formattable objects. If a subclass of Format receives a Formattable object type it doesn't handle (e.g., if a numeric Formattable is passed to a DateFormat object) then it returns a failing UErrorCode.
obj | The object to format. |
appendTo | Output parameter to receive result. Result is appended to existing contents. |
posIter | On return, can be used to iterate over positions of fields generated by this format call. |
status | Output param filled with success/failure status. |
Reimplemented from icu::Format.
UnicodeString & icu::Format::format | ( | const Formattable & | obj, |
UnicodeString & | appendTo, | ||
UErrorCode & | status | ||
) | const |
Formats an object to produce a string.
obj | The object to format. |
appendTo | Output parameter to receive result. Result is appended to existing contents. |
status | Output parameter filled in with success or failure status. |
UnicodeString icu::PluralFormat::format | ( | double | number, |
UErrorCode & | status | ||
) | const |
Formats a plural message for a given number.
number | a number for which the plural message should be formatted for. If no pattern has been applied to this PluralFormat object yet, the formatted number will be returned. |
status | output param set to success or failure code on exit, which must not indicate a failure before the function call. |
UnicodeString & icu::PluralFormat::format | ( | double | number, |
UnicodeString & | appendTo, | ||
FieldPosition & | pos, | ||
UErrorCode & | status | ||
) | const |
Formats a plural message for a given number.
number | a number for which the plural message should be formatted for. If no pattern has been applied to this PluralFormat object yet, the formatted number will be returned. |
appendTo | output parameter to receive result. result is appended to existing contents. |
pos | On input: an alignment field, if desired. On output: the offsets of the alignment field. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
UnicodeString icu::PluralFormat::format | ( | int32_t | number, |
UErrorCode & | status | ||
) | const |
Formats a plural message for a given number.
number | a number for which the plural message should be formatted for. If no pattern has been applied to this PluralFormat object yet, the formatted number will be returned. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
UnicodeString & icu::PluralFormat::format | ( | int32_t | number, |
UnicodeString & | appendTo, | ||
FieldPosition & | pos, | ||
UErrorCode & | status | ||
) | const |
Formats a plural message for a given number.
number | a number for which the plural message should be formatted for. If no pattern has been applied to this PluralFormat object yet, the formatted number will be returned. |
appendTo | output parameter to receive result. result is appended to existing contents. |
pos | On input: an alignment field, if desired. On output: the offsets of the alignment field. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
ICU "poor man's RTTI", returns a UClassID for the actual class.
Reimplemented from icu::UObject.
ICU "poor man's RTTI", returns a UClassID for this class.
Return true if another object is semantically unequal to this one.
other | the PluralFormat object to be compared with. |
PluralFormat & icu::PluralFormat::operator= | ( | const PluralFormat & | other | ) |
Return true if another object is semantically equal to this one.
other | the PluralFormat object to be compared with. |
Implements icu::Format.
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overridevirtual |
This method is not yet supported by PluralFormat
.
Before calling, set parse_pos.index to the offset you want to start parsing at in the source. After calling, parse_pos.index is the end of the text you parsed. If error occurs, index is unchanged.
When parsing, leading whitespace is discarded (with a successful parse), while trailing whitespace is left as is.
See Format::parseObject() for more.
source | The string to be parsed into an object. |
result | Formattable to be set to the parse result. If parse fails, return contents are undefined. |
parse_pos | The position to start parsing at. Upon return this param is set to the position after the last character successfully parsed. If the source is not parsed successfully, this param will remain unchanged. |
Implements icu::Format.
void icu::PluralFormat::setLocale | ( | const Locale & | locale, |
UErrorCode & | status | ||
) |
Sets the locale used by this PluraFormat
object.
Note: Calling this method resets this PluraFormat
object, i.e., a pattern that was applied previously will be removed, and the NumberFormat is set to the default number format for the locale. The resulting format behaves the same as one constructed from PluralFormat(const Locale& locale, UPluralType type, UErrorCode& status)
with UPLURAL_TYPE_CARDINAL.
locale | the locale to use to configure the formatter. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
void icu::PluralFormat::setNumberFormat | ( | const NumberFormat * | format, |
UErrorCode & | status | ||
) |
Sets the number format used by this formatter.
You only need to call this if you want a different number format than the default formatter for the locale.
format | the number format to use. |
status | output param set to success/failure code on exit, which must not indicate a failure before the function call. |
UnicodeString & icu::PluralFormat::toPattern | ( | UnicodeString & | appendTo | ) |
Returns the pattern from applyPattern() or constructor().
appendTo | output parameter to receive result. Result is appended to existing contents. |
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friend |