/* ******************************************************************************* * Copyright (C) 2007-2010, International Business Machines Corporation and * others. All Rights Reserved. ******************************************************************************* * * File PLURFMT.H * * Modification History:* * Date Name Description * ******************************************************************************** */ #ifndef PLURFMT #define PLURFMT #include "unicode/utypes.h" /** * \file * \brief C++ API: PluralFormat object */ #if !UCONFIG_NO_FORMATTING #include "unicode/numfmt.h" #include "unicode/plurrule.h" U_NAMESPACE_BEGIN class Hashtable; /** * <p> * <code>PluralFormat</code> supports the creation of internationalized * messages with plural inflection. It is based on <i>plural * selection</i>, i.e. the caller specifies messages for each * plural case that can appear in the users language and the * <code>PluralFormat</code> selects the appropriate message based on * the number. * </p> * <h4>The Problem of Plural Forms in Internationalized Messages</h4> * <p> * 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 <i>all</i> languages correctly. <code>ChoiceFormat</code> * 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., paucal applies to * numbers ending with 2, 3, or 4 except those ending with 12, 13, or * 14). Thus <code>ChoiceFormat</code> is not adequate. * </p><p> * <code>PluralFormat</code> deals with this by breaking the problem * into two parts: * <ul> * <li>It uses <code>PluralRules</code> 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. * <li>It provides predefined plural rules for many locales. Thus, the programmer * need not worry about the plural cases of a language. On the flip side, * the localizer does not have to specify the plural cases; he can simply * use the predefined keywords. The whole plural formatting of messages can * be done using localized patterns from resource bundles. For predefined plural * rules, see CLDR <i>Language Plural Rules</i> page at * http://unicode.org/repos/cldr-tmp/trunk/diff/supplemental/language_plural_rules.html * </ul> * </p> * <h4>Usage of <code>PluralFormat</code></h4> * <p> * This discussion assumes that you use <code>PluralFormat</code> with * a predefined set of plural rules. You can create one using one of * the constructors that takes a <code>locale</code> object. To * specify the message pattern, you can either pass it to the * constructor or set it explicitly using the * <code>applyPattern()</code> method. The <code>format()</code> * method takes a number object and selects the message of the * matching plural case. This message will be returned. * </p> * <h5>Patterns and Their Interpretation</h5> * <p> * The pattern text defines the message output for each plural case of the * used locale. The pattern is a sequence of * <code><i>caseKeyword</i>{<i>message</i>}</code> clauses, separated by white * space characters. Each clause assigns the message <code><i>message</i></code> * to the plural case identified by <code><i>caseKeyword</i></code>. * </p><p> * There are 6 predefined casekeyword in ICU - 'zero', 'one', 'two', 'few', 'many' and * 'other'. You always have to define a message text for the default plural case * "<code>other</code>" which is contained in every rule set. If the plural * rules of the <code>PluralFormat</code> object do not contain a plural case * identified by <code><i>caseKeyword</i></code>, U_DEFAULT_KEYWORD_MISSING * will be set to status. * If you do not specify a message text for a particular plural case, the * message text of the plural case "<code>other</code>" gets assigned to this * plural case. If you specify more than one message for the same plural case, * U_DUPLICATE_KEYWORD will be set to status. * <br> * Spaces between <code><i>caseKeyword</i></code> and * <code><i>message</i></code> will be ignored; spaces within * <code><i>message</i></code> will be preserved. * </p><p> * The message text for a particular plural case may contain other message * format patterns. <code>PluralFormat</code> preserves these so that you * can use the strings produced by <code>PluralFormat</code> with other * formatters. If you are using <code>PluralFormat</code> inside a * <code>MessageFormat</code> pattern, <code>MessageFormat</code> will * automatically evaluate the resulting format pattern.<br> * Thus, curly braces (<code>{</code>, <code>}</code>) are <i>only</i> allowed * in message texts to define a nested format pattern.<br> * The pound sign (<code>#</code>) will be interpreted as the number placeholder * in the message text, if it is not contained in curly braces (to preserve * <code>NumberFormat</code> patterns). <code>PluralFormat</code> will * replace each of those pound signs by the number passed to the * <code>format()</code> method. It will be formatted using a * <code>NumberFormat</code> for the <code>PluralFormat</code>'s locale. If you * need special number formatting, you have to explicitly specify a * <code>NumberFormat</code> for the <code>PluralFormat</code> to use. * </p> * Example * <pre> * \code * UErrorCode status = U_ZERO_ERROR; * MessageFormat* msgFmt = new MessageFormat(UnicodeString("{0, plural, * one{{0, number, C''est #,##0.0# fichier}} other {Ce sont # fichiers}} dans la liste."), * Locale("fr"), status); * if (U_FAILURE(status)) { * return; * } * Formattable args1[] = {(int32_t)0}; * Formattable args2[] = {(int32_t)3}; * FieldPosition ignore(FieldPosition::DONT_CARE); * UnicodeString result; * msgFmt->format(args1, 1, result, ignore, status); * cout << result << endl; * result.remove(); * msgFmt->format(args2, 1, result, ignore, status); * cout << result << endl; * \endcode * </pre> * Produces the output:<br> * <code>C'est 0,0 fichier dans la liste.</code><br> * <code>Ce sont 3 fichiers dans la liste.</code> * <p> * <strong>Note:</strong><br> * Currently <code>PluralFormat</code> * does not make use of quotes like <code>MessageFormat</code>. * If you use plural format strings with <code>MessageFormat</code> and want * to use a quote sign <code>'</code>, you have to write <code>''</code>. * <code>MessageFormat</code> unquotes this pattern and passes the unquoted * pattern to <code>PluralFormat</code>. It's a bit trickier if you use * nested formats that do quoting. In the example above, we wanted to insert * <code>'</code> in the number format pattern. Since * <code>NumberFormat</code> supports quotes, we had to insert * <code>''</code>. But since <code>MessageFormat</code> unquotes the * pattern before it gets passed to <code>PluralFormat</code>, we have to * double these quotes, i.e. write <code>''''</code>. * </p> * <h4>Defining Custom Plural Rules</h4> * <p>If you need to use <code>PluralFormat</code> with custom rules, you can * create a <code>PluralRules</code> object and pass it to * <code>PluralFormat</code>'s constructor. If you also specify a locale in this * constructor, this locale will be used to format the number in the message * texts. * </p><p> * For more information about <code>PluralRules</code>, see * {@link PluralRules}. * </p> * * ported from Java * @stable ICU 4.0 */ class U_I18N_API PluralFormat : public Format { public: /** * Creates a new <code>PluralFormat</code> for the default locale. * This locale will be used to get the set of plural rules and for standard * number formatting. * @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 */ PluralFormat(UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given locale. * @param locale the <code>PluralFormat</code> will be configured with * rules for this locale. This locale will also be used for * standard number formatting. * @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 */ PluralFormat(const Locale& locale, UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given set of rules. * The standard number formatting will be done using the default locale. * @param rules defines the behavior of the <code>PluralFormat</code> * object. * @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 */ PluralFormat(const PluralRules& rules, UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given set of rules. * The standard number formatting will be done using the given locale. * @param locale the default number formatting will be done using this * locale. * @param rules defines the behavior of the <code>PluralFormat</code> * object. * @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 */ PluralFormat(const Locale& locale, const PluralRules& rules, UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given pattern string. * The default locale will be used to get the set of plural rules and for * standard number formatting. * @param pattern the pattern for this <code>PluralFormat</code>. * errors are returned to status if the pattern is invalid. * @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 */ PluralFormat(const UnicodeString& pattern, UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given pattern string and * locale. * The locale will be used to get the set of plural rules and for * standard number formatting. * @param locale the <code>PluralFormat</code> will be configured with * rules for this locale. This locale will also be used for * standard number formatting. * @param pattern the pattern for this <code>PluralFormat</code>. * errors are returned to status if the pattern is invalid. * @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 */ PluralFormat(const Locale& locale, const UnicodeString& pattern, UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given set of rules, a * pattern and a locale. * @param rules defines the behavior of the <code>PluralFormat</code> * object. * @param pattern the pattern for this <code>PluralFormat</code>. * errors are returned to status if the pattern is invalid. * @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 */ PluralFormat(const PluralRules& rules, const UnicodeString& pattern, UErrorCode& status); /** * Creates a new <code>PluralFormat</code> for a given set of rules, a * pattern and a locale. * @param locale the <code>PluralFormat</code> will be configured with * rules for this locale. This locale will also be used for * standard number formatting. * @param rules defines the behavior of the <code>PluralFormat</code> * object. * @param pattern the pattern for this <code>PluralFormat</code>. * errors are returned to status if the pattern is invalid. * @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 */ PluralFormat(const Locale& locale, const PluralRules& rules, const UnicodeString& pattern, UErrorCode& status); /** * copy constructor. * @stable ICU 4.0 */ PluralFormat(const PluralFormat& other); /** * Destructor. * @stable ICU 4.0 */ virtual ~PluralFormat(); /** * 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. * * @param pattern the pattern for this plural format * errors are returned to status if the pattern is invalid. * @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 */ void applyPattern(const UnicodeString& pattern, UErrorCode& status); using Format::format; /** * Formats a plural message for a given number. * * @param number a number for which the plural message should be formatted * for. If no pattern has been applied to this * <code>PluralFormat</code> object yet, the formatted number * will be returned. * @param status output param set to success/failure code on exit, which * must not indicate a failure before the function call. * @return the string containing the formatted plural message. * @stable ICU 4.0 */ UnicodeString format(int32_t number, UErrorCode& status) const; /** * Formats a plural message for a given number. * * @param 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. * @param status output param set to success or failure code on exit, which * must not indicate a failure before the function call. * @return the string containing the formatted plural message. * @stable ICU 4.0 */ UnicodeString format(double number, UErrorCode& status) const; /** * Formats a plural message for a given number. * * @param number a number for which the plural message should be formatted * for. If no pattern has been applied to this * <code>PluralFormat</code> object yet, the formatted number * will be returned. * @param appendTo output parameter to receive result. * result is appended to existing contents. * @param pos On input: an alignment field, if desired. * On output: the offsets of the alignment field. * @param status output param set to success/failure code on exit, which * must not indicate a failure before the function call. * @return the string containing the formatted plural message. * @stable ICU 4.0 */ UnicodeString& format(int32_t number, UnicodeString& appendTo, FieldPosition& pos, UErrorCode& status) const; /** * Formats a plural message for a given number. * * @param 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. * @param appendTo output parameter to receive result. * result is appended to existing contents. * @param pos On input: an alignment field, if desired. * On output: the offsets of the alignment field. * @param status output param set to success/failure code on exit, which * must not indicate a failure before the function call. * @return the string containing the formatted plural message. * @stable ICU 4.0 */ UnicodeString& format(double number, UnicodeString& appendTo, FieldPosition& pos, UErrorCode& status) const; /** * Sets the locale used by this <code>PluraFormat</code> object. * Note: Calling this method resets this <code>PluraFormat</code> 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 {@link #PluralFormat(const Locale& locale, UErrorCode& status)}. * @param locale the <code>locale</code> to use to configure the formatter. * @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 */ void setLocale(const Locale& locale, 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. * @param format the number format to use. * @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 */ void setNumberFormat(const NumberFormat* format, UErrorCode& status); /** * Assignment operator * * @param other the PluralFormat object to copy from. * @stable ICU 4.0 */ PluralFormat& operator=(const PluralFormat& other); /** * Return true if another object is semantically equal to this one. * * @param other the PluralFormat object to be compared with. * @return true if other is semantically equal to this. * @stable ICU 4.0 */ virtual UBool operator==(const Format& other) const; /** * Return true if another object is semantically unequal to this one. * * @param other the PluralFormat object to be compared with. * @return true if other is semantically unequal to this. * @stable ICU 4.0 */ virtual UBool operator!=(const Format& other) const; /** * Clones this Format object polymorphically. The caller owns the * result and should delete it when done. * @stable ICU 4.0 */ virtual Format* clone(void) const; /** * Redeclared Format method. * * @param obj The object to be formatted into a string. * @param appendTo output parameter to receive result. * Result is appended to existing contents. * @param pos On input: an alignment field, if desired. * On output: the offsets of the alignment field. * @param status output param filled with success/failure status. * @return Reference to 'appendTo' parameter. * @stable ICU 4.0 */ UnicodeString& format(const Formattable& obj, UnicodeString& appendTo, FieldPosition& pos, UErrorCode& status) const; /** * Returns the pattern from applyPattern() or constructor(). * * @param appendTo output parameter to receive result. * Result is appended to existing contents. * @return the UnicodeString with inserted pattern. * @stable ICU 4.0 */ UnicodeString& toPattern(UnicodeString& appendTo); /** * This method is not yet supported by <code>PluralFormat</code>. * <P> * 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. * <P> * When parsing, leading whitespace is discarded (with a successful parse), * while trailing whitespace is left as is. * <P> * See Format::parseObject() for more. * * @param source The string to be parsed into an object. * @param result Formattable to be set to the parse result. * If parse fails, return contents are undefined. * @param 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. * @stable ICU 4.0 */ virtual void parseObject(const UnicodeString& source, Formattable& result, ParsePosition& parse_pos) const; /** * 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: typedef enum fmtToken { none, tLetter, tNumber, tSpace, tNumberSign, tLeftBrace, tRightBrace }fmtToken; Locale locale; PluralRules* pluralRules; UnicodeString pattern; Hashtable *fParsedValuesHash; NumberFormat* numberFormat; NumberFormat* replacedNumberFormat; PluralFormat(); // default constructor not implemented void init(const PluralRules* rules, const Locale& curlocale, UErrorCode& status); UBool inRange(UChar ch, fmtToken& type); UBool checkSufficientDefinition(); void parsingFailure(); UnicodeString insertFormattedNumber(double number, UnicodeString& message, UnicodeString& appendTo, FieldPosition& pos) const; void copyHashtable(Hashtable *other, UErrorCode& status); }; U_NAMESPACE_END #endif /* #if !UCONFIG_NO_FORMATTING */ #endif // _PLURFMT //eof