tor-browser

selfmt.h (14691B)

---

// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
/********************************************************************
* COPYRIGHT:
* Copyright (c) 1997-2011, International Business Machines Corporation and
* others. All Rights Reserved.
* Copyright (C) 2010 , Yahoo! Inc.
********************************************************************
*
* File SELFMT.H
*
* Modification History:
*
*   Date        Name        Description
*   11/11/09    kirtig      Finished first cut of implementation.
********************************************************************/

#ifndef SELFMT
#define SELFMT

#include "unicode/utypes.h"

#if U_SHOW_CPLUSPLUS_API

#include "unicode/messagepattern.h"
#include "unicode/numfmt.h"

/**
* \file
* \brief C++ API: SelectFormat object
*/

#if !UCONFIG_NO_FORMATTING

U_NAMESPACE_BEGIN

class MessageFormat;

/**
 * <p><code>SelectFormat</code> supports the creation of  internationalized
 * messages by selecting phrases based on keywords. The pattern  specifies
 * how to map keywords to phrases and provides a default phrase. The
 * object provided to the format method is a string that's matched
 * against the keywords. If there is a match, the corresponding phrase
 * is selected; otherwise, the default phrase is used.</p>
 *
 * <h4>Using <code>SelectFormat</code> for Gender Agreement</h4>
 *
 * <p>Note: Typically, select formatting is done via <code>MessageFormat</code>
 * with a <code>select</code> argument type,
 * rather than using a stand-alone <code>SelectFormat</code>.</p>
 *
 * <p>The main use case for the select format is gender based  inflection.
 * When names or nouns are inserted into sentences, their gender can  affect pronouns,
 * verb forms, articles, and adjectives. Special care needs to be
 * taken for the case where the gender cannot be determined.
 * The impact varies between languages:</p>
 * \htmlonly
 * <ul>
 * <li>English has three genders, and unknown gender is handled as a  special
 * case. Names use the gender of the named person (if known), nouns  referring
 * to people use natural gender, and inanimate objects are usually  neutral.
 * The gender only affects pronouns: "he", "she", "it", "they".
 *
 * <li>German differs from English in that the gender of nouns is  rather
 * arbitrary, even for nouns referring to people ("M&#x00E4;dchen", girl, is  neutral).
 * The gender affects pronouns ("er", "sie", "es"), articles ("der",  "die",
 * "das"), and adjective forms ("guter Mann", "gute Frau", "gutes  M&#x00E4;dchen").
 *
 * <li>French has only two genders; as in German the gender of nouns
 * is rather arbitrary - for sun and moon, the genders
 * are the opposite of those in German. The gender affects
 * pronouns ("il", "elle"), articles ("le", "la"),
 * adjective forms ("bon", "bonne"), and sometimes
 * verb forms ("all&#x00E9;", "all&#x00E9;e").
 *
 * <li>Polish distinguishes five genders (or noun classes),
 * human masculine, animate non-human masculine, inanimate masculine,
 * feminine, and neuter.
 * </ul>
 * \endhtmlonly
 * <p>Some other languages have noun classes that are not related to  gender,
 * but similar in grammatical use.
 * Some African languages have around 20 noun classes.</p>
 *
 * <p><b>Note:</b>For the gender of a <i>person</i> in a given sentence,
 * we usually need to distinguish only between female, male and other/unknown.</p>
 *
 * <p>To enable localizers to create sentence patterns that take their
 * language's gender dependencies into consideration, software has to  provide
 * information about the gender associated with a noun or name to
 * <code>MessageFormat</code>.
 * Two main cases can be distinguished:</p>
 *
 * <ul>
 * <li>For people, natural gender information should be maintained  for each person.
 * Keywords like "male", "female", "mixed" (for groups of people)
 * and "unknown" could be used.
 *
 * <li>For nouns, grammatical gender information should be maintained  for
 * each noun and per language, e.g., in resource bundles.
 * The keywords "masculine", "feminine", and "neuter" are commonly  used,
 * but some languages may require other keywords.
 * </ul>
 *
 * <p>The resulting keyword is provided to <code>MessageFormat</code>  as a
 * parameter separate from the name or noun it's associated with. For  example,
 * to generate a message such as "Jean went to Paris", three separate  arguments
 * would be provided: The name of the person as argument 0, the  gender of
 * the person as argument 1, and the name of the city as argument 2.
 * The sentence pattern for English, where the gender of the person has
 * no impact on this simple sentence, would not refer to argument 1  at all:</p>
 *
 * <pre>{0} went to {2}.</pre>
 *
 * <p><b>Note:</b> The entire sentence should be included (and partially repeated)
 * inside each phrase. Otherwise translators would have to be trained on how to
 * move bits of the sentence in and out of the select argument of a message.
 * (The examples below do not follow this recommendation!)</p>
 *
 * <p>The sentence pattern for French, where the gender of the person affects
 * the form of the participle, uses a select format based on argument 1:</p>
 *
 * \htmlonly<pre>{0} est {1, select, female {all&#x00E9;e} other {all&#x00E9;}} &#x00E0; {2}.</pre>\endhtmlonly
 *
 * <p>Patterns can be nested, so that it's possible to handle  interactions of
 * number and gender where necessary. For example, if the above  sentence should
 * allow for the names of several people to be inserted, the  following sentence
 * pattern can be used (with argument 0 the list of people's names,
 * argument 1 the number of people, argument 2 their combined gender, and
 * argument 3 the city name):</p>
 *
 * \htmlonly
 * <pre>{0} {1, plural,
 *                 one {est {2, select, female {all&#x00E9;e} other  {all&#x00E9;}}}
 *                 other {sont {2, select, female {all&#x00E9;es} other {all&#x00E9;s}}}
 *          }&#x00E0; {3}.</pre>
 * \endhtmlonly
 *
 * <h4>Patterns and Their Interpretation</h4>
 *
 * <p>The <code>SelectFormat</code> pattern string defines the phrase output
 * for each user-defined keyword.
 * The pattern is a sequence of (keyword, message) pairs.
 * A keyword is a "pattern identifier": [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+</p>
 *
 * <p>Each message is a MessageFormat pattern string enclosed in {curly braces}.</p>
 *
 * <p>You always have to define a phrase for the default keyword
 * <code>other</code>; this phrase is returned when the keyword
 * provided to
 * the <code>format</code> method matches no other keyword.
 * If a pattern does not provide a phrase for <code>other</code>, the  method
 * it's provided to returns the error  <code>U_DEFAULT_KEYWORD_MISSING</code>.
 * <br>
 * Pattern_White_Space between keywords and messages is ignored.
 * Pattern_White_Space within a message is preserved and output.</p>
 *
 * <p><pre>Example:
 * \htmlonly
 *
 * UErrorCode status = U_ZERO_ERROR;
 * MessageFormat *msgFmt = new MessageFormat(UnicodeString("{0} est  {1, select, female {all&#x00E9;e} other {all&#x00E9;}} &#x00E0; Paris."), Locale("fr"),  status);
 * if (U_FAILURE(status)) {
 *       return;
 * }
 * FieldPosition ignore(FieldPosition::DONT_CARE);
 * UnicodeString result;
 *
 * char* str1= "Kirti,female";
 * Formattable args1[] = {"Kirti","female"};
 * msgFmt->format(args1, 2, result, ignore, status);
 * cout << "Input is " << str1 << " and result is: " << result << endl;
 * delete msgFmt;
 *
 * \endhtmlonly
 * </pre>
 * </p>
 *
 * Produces the output:<br>
 * \htmlonly
 * <code>Kirti est all&#x00E9;e &#x00E0; Paris.</code>
 * \endhtmlonly
 *
 * @stable ICU 4.4
 */

class U_I18N_API SelectFormat : public Format {
public:

   /**
    * Creates a new <code>SelectFormat</code> for a given pattern string.
    * @param  pattern the pattern for this <code>SelectFormat</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 4.4
    */
   SelectFormat(const UnicodeString& pattern, UErrorCode& status);

   /**
    * copy constructor.
    * @stable ICU 4.4
    */
   SelectFormat(const SelectFormat& other);

   /**
    * Destructor.
    * @stable ICU 4.4
    */
   virtual ~SelectFormat();

   /**
    * Sets the pattern used by this select format.
    * for the keyword rules.
    * Patterns and their interpretation are specified in the class description.
    *
    * @param pattern the pattern for this select 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 4.4
    */
   void applyPattern(const UnicodeString& pattern, UErrorCode& status);


   using Format::format;

   /**
    * Selects the phrase for  the given keyword
    *
    * @param keyword  The keyword that is used to select an alternative.
    * @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         Reference to 'appendTo' parameter.
    * @stable ICU 4.4
    */
   UnicodeString& format(const UnicodeString& keyword,
                           UnicodeString& appendTo,
                           FieldPosition& pos,
                           UErrorCode& status) const;

   /**
    * Assignment operator
    *
    * @param other    the SelectFormat object to copy from.
    * @stable ICU 4.4
    */
   SelectFormat& operator=(const SelectFormat& other);

   /**
    * Return true if another object is semantically equal to this one.
    *
    * @param other    the SelectFormat object to be compared with.
    * @return         true if other is semantically equal to this.
    * @stable ICU 4.4
    */
   virtual bool operator==(const Format& other) const override;

   /**
    * Return true if another object is semantically unequal to this one.
    *
    * @param other    the SelectFormat object to be compared with.
    * @return         true if other is semantically unequal to this.
    * @stable ICU 4.4
    */
   virtual bool operator!=(const Format& other) const;

   /**
    * Clones this Format object polymorphically.  The caller owns the
    * result and should delete it when done.
    * @stable ICU 4.4
    */
   virtual SelectFormat* clone() const override;

   /**
    * Format an object to produce a string.
    * This method handles keyword strings.
    * If the Formattable object is not a <code>UnicodeString</code>,
    * then it returns a failing UErrorCode.
    *
    * @param obj       A keyword string that is used to select an alternative.
    * @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 4.4
    */
   UnicodeString& format(const Formattable& obj,
                        UnicodeString& appendTo,
                        FieldPosition& pos,
                        UErrorCode& status) const override;

   /**
    * 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 4.4
    */
   UnicodeString& toPattern(UnicodeString& appendTo);

   /**
    * This method is not yet supported by <code>SelectFormat</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 4.4
    */
   virtual void parseObject(const UnicodeString& source,
                           Formattable& result,
                           ParsePosition& parse_pos) const override;

   /**
    * ICU "poor man's RTTI", returns a UClassID for this class.
    * @stable ICU 4.4
    */
   static UClassID U_EXPORT2 getStaticClassID();

   /**
    * ICU "poor man's RTTI", returns a UClassID for the actual class.
    * @stable ICU 4.4
    */
   virtual UClassID getDynamicClassID() const override;

private:
   friend class MessageFormat;

   SelectFormat() = delete;   // default constructor not implemented.

   /**
    * Finds the SelectFormat sub-message for the given keyword, or the "other" sub-message.
    * @param pattern A MessagePattern.
    * @param partIndex the index of the first SelectFormat argument style part.
    * @param keyword a keyword to be matched to one of the SelectFormat argument's keywords.
    * @param ec Error code.
    * @return the sub-message start part index.
    */
   static int32_t findSubMessage(const MessagePattern& pattern, int32_t partIndex,
                                 const UnicodeString& keyword, UErrorCode& ec);

   MessagePattern msgPattern;
};

U_NAMESPACE_END

#endif /* #if !UCONFIG_NO_FORMATTING */

#endif /* U_SHOW_CPLUSPLUS_API */

#endif // _SELFMT
//eof