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// © 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 ("Mädchen", girl, is neutral).
* The gender affects pronouns ("er", "sie", "es"), articles ("der", "die",
* "das"), and adjective forms ("guter Mann", "gute Frau", "gutes Mädchen").
*
* <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 ("allé", "allée").
*
* <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 {allée} other {allé}} à {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 {allée} other {allé}}}
* other {sont {2, select, female {allées} other {allés}}}
* }à {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 {allée} other {allé}} à 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 allée à 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(void);
/**
* 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