• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 // © 2016 and later: Unicode, Inc. and others.
2 // License & terms of use: http://www.unicode.org/copyright.html
3 /********************************************************************
4  * COPYRIGHT:
5  * Copyright (c) 1997-2011, International Business Machines Corporation and
6  * others. All Rights Reserved.
7  * Copyright (C) 2010 , Yahoo! Inc.
8  ********************************************************************
9  *
10  * File SELFMT.H
11  *
12  * Modification History:
13  *
14  *   Date        Name        Description
15  *   11/11/09    kirtig      Finished first cut of implementation.
16  ********************************************************************/
17 
18 #ifndef SELFMT
19 #define SELFMT
20 
21 #include "unicode/messagepattern.h"
22 #include "unicode/numfmt.h"
23 #include "unicode/utypes.h"
24 
25 /**
26  * \file
27  * \brief C++ API: SelectFormat object
28  */
29 
30 #if !UCONFIG_NO_FORMATTING
31 
32 U_NAMESPACE_BEGIN
33 
34 class MessageFormat;
35 
36 /**
37   * <p><code>SelectFormat</code> supports the creation of  internationalized
38   * messages by selecting phrases based on keywords. The pattern  specifies
39   * how to map keywords to phrases and provides a default phrase. The
40   * object provided to the format method is a string that's matched
41   * against the keywords. If there is a match, the corresponding phrase
42   * is selected; otherwise, the default phrase is used.</p>
43   *
44   * <h4>Using <code>SelectFormat</code> for Gender Agreement</h4>
45   *
46   * <p>Note: Typically, select formatting is done via <code>MessageFormat</code>
47   * with a <code>select</code> argument type,
48   * rather than using a stand-alone <code>SelectFormat</code>.</p>
49   *
50   * <p>The main use case for the select format is gender based  inflection.
51   * When names or nouns are inserted into sentences, their gender can  affect pronouns,
52   * verb forms, articles, and adjectives. Special care needs to be
53   * taken for the case where the gender cannot be determined.
54   * The impact varies between languages:</p>
55   * \htmlonly
56   * <ul>
57   * <li>English has three genders, and unknown gender is handled as a  special
58   * case. Names use the gender of the named person (if known), nouns  referring
59   * to people use natural gender, and inanimate objects are usually  neutral.
60   * The gender only affects pronouns: "he", "she", "it", "they".
61   *
62   * <li>German differs from English in that the gender of nouns is  rather
63   * arbitrary, even for nouns referring to people ("M&#x00E4;dchen", girl, is  neutral).
64   * The gender affects pronouns ("er", "sie", "es"), articles ("der",  "die",
65   * "das"), and adjective forms ("guter Mann", "gute Frau", "gutes  M&#x00E4;dchen").
66   *
67   * <li>French has only two genders; as in German the gender of nouns
68   * is rather arbitrary - for sun and moon, the genders
69   * are the opposite of those in German. The gender affects
70   * pronouns ("il", "elle"), articles ("le", "la"),
71   * adjective forms ("bon", "bonne"), and sometimes
72   * verb forms ("all&#x00E9;", "all&#x00E9;e").
73   *
74   * <li>Polish distinguishes five genders (or noun classes),
75   * human masculine, animate non-human masculine, inanimate masculine,
76   * feminine, and neuter.
77   * </ul>
78   * \endhtmlonly
79   * <p>Some other languages have noun classes that are not related to  gender,
80   * but similar in grammatical use.
81   * Some African languages have around 20 noun classes.</p>
82   *
83   * <p><b>Note:</b>For the gender of a <i>person</i> in a given sentence,
84   * we usually need to distinguish only between female, male and other/unknown.</p>
85   *
86   * <p>To enable localizers to create sentence patterns that take their
87   * language's gender dependencies into consideration, software has to  provide
88   * information about the gender associated with a noun or name to
89   * <code>MessageFormat</code>.
90   * Two main cases can be distinguished:</p>
91   *
92   * <ul>
93   * <li>For people, natural gender information should be maintained  for each person.
94   * Keywords like "male", "female", "mixed" (for groups of people)
95   * and "unknown" could be used.
96   *
97   * <li>For nouns, grammatical gender information should be maintained  for
98   * each noun and per language, e.g., in resource bundles.
99   * The keywords "masculine", "feminine", and "neuter" are commonly  used,
100   * but some languages may require other keywords.
101   * </ul>
102   *
103   * <p>The resulting keyword is provided to <code>MessageFormat</code>  as a
104   * parameter separate from the name or noun it's associated with. For  example,
105   * to generate a message such as "Jean went to Paris", three separate  arguments
106   * would be provided: The name of the person as argument 0, the  gender of
107   * the person as argument 1, and the name of the city as argument 2.
108   * The sentence pattern for English, where the gender of the person has
109   * no impact on this simple sentence, would not refer to argument 1  at all:</p>
110   *
111   * <pre>{0} went to {2}.</pre>
112   *
113   * <p><b>Note:</b> The entire sentence should be included (and partially repeated)
114   * inside each phrase. Otherwise translators would have to be trained on how to
115   * move bits of the sentence in and out of the select argument of a message.
116   * (The examples below do not follow this recommendation!)</p>
117   *
118   * <p>The sentence pattern for French, where the gender of the person affects
119   * the form of the participle, uses a select format based on argument 1:</p>
120   *
121   * \htmlonly<pre>{0} est {1, select, female {all&#x00E9;e} other {all&#x00E9;}} &#x00E0; {2}.</pre>\endhtmlonly
122   *
123   * <p>Patterns can be nested, so that it's possible to handle  interactions of
124   * number and gender where necessary. For example, if the above  sentence should
125   * allow for the names of several people to be inserted, the  following sentence
126   * pattern can be used (with argument 0 the list of people's names,
127   * argument 1 the number of people, argument 2 their combined gender, and
128   * argument 3 the city name):</p>
129   *
130   * \htmlonly
131   * <pre>{0} {1, plural,
132   *                 one {est {2, select, female {all&#x00E9;e} other  {all&#x00E9;}}}
133   *                 other {sont {2, select, female {all&#x00E9;es} other {all&#x00E9;s}}}
134   *          }&#x00E0; {3}.</pre>
135   * \endhtmlonly
136   *
137   * <h4>Patterns and Their Interpretation</h4>
138   *
139   * <p>The <code>SelectFormat</code> pattern string defines the phrase output
140   * for each user-defined keyword.
141   * The pattern is a sequence of (keyword, message) pairs.
142   * A keyword is a "pattern identifier": [^[[:Pattern_Syntax:][:Pattern_White_Space:]]]+</p>
143   *
144   * <p>Each message is a MessageFormat pattern string enclosed in {curly braces}.</p>
145   *
146   * <p>You always have to define a phrase for the default keyword
147   * <code>other</code>; this phrase is returned when the keyword
148   * provided to
149   * the <code>format</code> method matches no other keyword.
150   * If a pattern does not provide a phrase for <code>other</code>, the  method
151   * it's provided to returns the error  <code>U_DEFAULT_KEYWORD_MISSING</code>.
152   * <br>
153   * Pattern_White_Space between keywords and messages is ignored.
154   * Pattern_White_Space within a message is preserved and output.</p>
155   *
156   * <p><pre>Example:
157   * \htmlonly
158   *
159   * UErrorCode status = U_ZERO_ERROR;
160   * MessageFormat *msgFmt = new MessageFormat(UnicodeString("{0} est  {1, select, female {all&#x00E9;e} other {all&#x00E9;}} &#x00E0; Paris."), Locale("fr"),  status);
161   * if (U_FAILURE(status)) {
162   *       return;
163   * }
164   * FieldPosition ignore(FieldPosition::DONT_CARE);
165   * UnicodeString result;
166   *
167   * char* str1= "Kirti,female";
168   * Formattable args1[] = {"Kirti","female"};
169   * msgFmt->format(args1, 2, result, ignore, status);
170   * cout << "Input is " << str1 << " and result is: " << result << endl;
171   * delete msgFmt;
172   *
173   * \endhtmlonly
174   * </pre>
175   * </p>
176   *
177   * Produces the output:<br>
178   * \htmlonly
179   * <code>Kirti est all&#x00E9;e &#x00E0; Paris.</code>
180   * \endhtmlonly
181   *
182   * @stable ICU 4.4
183   */
184 
185 class U_I18N_API SelectFormat : public Format {
186 public:
187 
188     /**
189      * Creates a new <code>SelectFormat</code> for a given pattern string.
190      * @param  pattern the pattern for this <code>SelectFormat</code>.
191      *                 errors are returned to status if the pattern is invalid.
192      * @param status   output param set to success/failure code on exit, which
193      *                 must not indicate a failure before the function call.
194      * @stable ICU 4.4
195      */
196     SelectFormat(const UnicodeString& pattern, UErrorCode& status);
197 
198     /**
199      * copy constructor.
200      * @stable ICU 4.4
201      */
202     SelectFormat(const SelectFormat& other);
203 
204     /**
205      * Destructor.
206      * @stable ICU 4.4
207      */
208     virtual ~SelectFormat();
209 
210     /**
211      * Sets the pattern used by this select format.
212      * for the keyword rules.
213      * Patterns and their interpretation are specified in the class description.
214      *
215      * @param pattern the pattern for this select format
216      *                errors are returned to status if the pattern is invalid.
217      * @param status  output param set to success/failure code on exit, which
218      *                must not indicate a failure before the function call.
219      * @stable ICU 4.4
220      */
221     void applyPattern(const UnicodeString& pattern, UErrorCode& status);
222 
223 
224     using Format::format;
225 
226     /**
227      * Selects the phrase for  the given keyword
228      *
229      * @param keyword  The keyword that is used to select an alternative.
230      * @param appendTo output parameter to receive result.
231      *                 result is appended to existing contents.
232      * @param pos      On input: an alignment field, if desired.
233      *                 On output: the offsets of the alignment field.
234      * @param status  output param set to success/failure code on exit, which
235      *                 must not indicate a failure before the function call.
236      * @return         Reference to 'appendTo' parameter.
237      * @stable ICU 4.4
238      */
239     UnicodeString& format(const UnicodeString& keyword,
240                             UnicodeString& appendTo,
241                             FieldPosition& pos,
242                             UErrorCode& status) const;
243 
244     /**
245      * Assignment operator
246      *
247      * @param other    the SelectFormat object to copy from.
248      * @stable ICU 4.4
249      */
250     SelectFormat& operator=(const SelectFormat& other);
251 
252     /**
253      * Return true if another object is semantically equal to this one.
254      *
255      * @param other    the SelectFormat object to be compared with.
256      * @return         true if other is semantically equal to this.
257      * @stable ICU 4.4
258      */
259     virtual UBool operator==(const Format& other) const;
260 
261     /**
262      * Return true if another object is semantically unequal to this one.
263      *
264      * @param other    the SelectFormat object to be compared with.
265      * @return         true if other is semantically unequal to this.
266      * @stable ICU 4.4
267      */
268     virtual UBool operator!=(const Format& other) const;
269 
270     /**
271      * Clones this Format object polymorphically.  The caller owns the
272      * result and should delete it when done.
273      * @stable ICU 4.4
274      */
275     virtual Format* clone(void) const;
276 
277     /**
278      * Format an object to produce a string.
279      * This method handles keyword strings.
280      * If the Formattable object is not a <code>UnicodeString</code>,
281      * then it returns a failing UErrorCode.
282      *
283      * @param obj       A keyword string that is used to select an alternative.
284      * @param appendTo  output parameter to receive result.
285      *                  Result is appended to existing contents.
286      * @param pos       On input: an alignment field, if desired.
287      *                  On output: the offsets of the alignment field.
288      * @param status    output param filled with success/failure status.
289      * @return          Reference to 'appendTo' parameter.
290      * @stable ICU 4.4
291      */
292     UnicodeString& format(const Formattable& obj,
293                          UnicodeString& appendTo,
294                          FieldPosition& pos,
295                          UErrorCode& status) const;
296 
297     /**
298      * Returns the pattern from applyPattern() or constructor.
299      *
300      * @param  appendTo  output parameter to receive result.
301      *                  Result is appended to existing contents.
302      * @return the UnicodeString with inserted pattern.
303      * @stable ICU 4.4
304      */
305     UnicodeString& toPattern(UnicodeString& appendTo);
306 
307     /**
308      * This method is not yet supported by <code>SelectFormat</code>.
309      * <P>
310      * Before calling, set parse_pos.index to the offset you want to start
311      * parsing at in the source. After calling, parse_pos.index is the end of
312      * the text you parsed. If error occurs, index is unchanged.
313      * <P>
314      * When parsing, leading whitespace is discarded (with a successful parse),
315      * while trailing whitespace is left as is.
316      * <P>
317      * See Format::parseObject() for more.
318      *
319      * @param source     The string to be parsed into an object.
320      * @param result     Formattable to be set to the parse result.
321      *     If parse fails, return contents are undefined.
322      * @param parse_pos The position to start parsing at. Upon return
323      *     this param is set to the position after the
324      *     last character successfully parsed. If the
325      *     source is not parsed successfully, this param
326      *     will remain unchanged.
327      * @stable ICU 4.4
328      */
329     virtual void parseObject(const UnicodeString& source,
330                             Formattable& result,
331                             ParsePosition& parse_pos) const;
332 
333     /**
334      * ICU "poor man's RTTI", returns a UClassID for this class.
335      * @stable ICU 4.4
336      */
337     static UClassID U_EXPORT2 getStaticClassID(void);
338 
339     /**
340      * ICU "poor man's RTTI", returns a UClassID for the actual class.
341      * @stable ICU 4.4
342      */
343     virtual UClassID getDynamicClassID() const;
344 
345 private:
346     friend class MessageFormat;
347 
348     SelectFormat();   // default constructor not implemented.
349 
350     /**
351      * Finds the SelectFormat sub-message for the given keyword, or the "other" sub-message.
352      * @param pattern A MessagePattern.
353      * @param partIndex the index of the first SelectFormat argument style part.
354      * @param keyword a keyword to be matched to one of the SelectFormat argument's keywords.
355      * @param ec Error code.
356      * @return the sub-message start part index.
357      */
358     static int32_t findSubMessage(const MessagePattern& pattern, int32_t partIndex,
359                                   const UnicodeString& keyword, UErrorCode& ec);
360 
361     MessagePattern msgPattern;
362 };
363 
364 U_NAMESPACE_END
365 
366 #endif /* #if !UCONFIG_NO_FORMATTING */
367 
368 #endif // _SELFMT
369 //eof
370