Help:Extension:ParserFunctions/pt

= Funções adicionais do analisador sintáctico = Se a extensão foi instalada na sua wiki, ela fornece dez funções adicionais ao analisador sintáctico, que suplementam as palavras mágicas já presentes no MediaWiki. Todas as funções fornecidas pela extensão têm a forma:
 *  

#expr

 *  

Esta função calcula a expressão matemática e retorna o resultado. Portanto:


 *   &rarr; 

Os operadores matemáticos disponíveis estão listados na tabela da direita, por ordem decrescente de precedência. Para mais detalhes sobre cada operador, consulte.

A precisão e formato do resultado variam de acordo com o sistema operativo do servidor que está a executar o MediaWiki e com o formato numérico da língua do site.

Nos operadores de lógica Booleana, zero tem o valor falso e qualquer outro número, positivo ou negativo, tem o valor verdadeiro:


 *   &rarr; 
 *   &rarr; 
 *   &rarr; 
 *  </tt> &rarr; 

Uma expressão de entrada vazia retorna uma expressão de saída vazia:


 *  </tt> &rarr;  

Expressões inválidas retornam uma ou várias mensagens de erro, que podem ser apanhadas usando a função #iferror</tt>:


 *  </tt> &rarr; 
 *  </tt> &rarr; 

Algumas expressões podem resultar em erros de vírgula flutuante (floating-point) quando são usados números muito grandes ou muito pequenos:


 *  </tt> &rarr; 

retorna 3259 na maioria das vezes, mas ocasionalmente retorna -6357. Isto varia com as especificações e a configuração do servidor que executa a wiki (ver ).

#if

 *  </tt>

Esta função testa se o seu primeiro parâmetro tem conteúdo ou está vazio. Se tem conteúdo, retorna o valor se verdadeiro</tt>. Se está vazio, ou só contém caracteres em branco (espaços, nova linhas, etc.), retorna o valor se falso</tt>.


 *  </tt> &rarr; 
 *  </tt> &rarr; 
 *  </tt> &rarr; 
 *  </tt> &rarr; 

O texto do primeiro parâmetro é sempre interpretado como texto puro, portanto expressões matemáticas não são calculadas:


 *  </tt> &rarr; 

Qualquer um dos valores a retornar, ou ambos, podem ser omitidos:


 *  </tt> &rarr;  
 *  </tt> &rarr;  
 * <tt> </tt> &rarr;  

Para mais exemplos do uso desta função, consulte funções do analisador sintáctico nas predefinições.

#ifeq

 * <tt> </tt>

Esta função compara dois textos e determina se são idênticos.

Se ambos tiverem valores numéricos válidos, são comparados numericamente:


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

Caso contrário, são comparados como texto; esta comparação é sensível a maiúsculas e minúsculas:


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

O uso de elementos sintácticos nos textos (tais como <tt>  </tt>) resulta em erros:


 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;  

#iferror

 * <tt> </tt>

Esta função calcula a expressão e verifica se ocorre um erro no cálculo. Se ocorrer um erro, retorna o <tt>valor se verdadeiro</tt>. Se não, retorna o <tt>valor se falso</tt>.


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * porque <tt> </tt> &rarr; 

Um erro ocorre quando o resultado do cálculo contém um objecto HTML com <tt>class="error"</tt>. Este objecto pode ser gerado por outras funções do analisador sintáctico, como <tt>#expr</tt>, <tt>#time</tt> e <tt>#rel2abs</tt>, por erros em predefinições como ciclos e recursão, ou por outros erros (failsoft) detectados pelo analisador sintáctico.

Qualquer um dos valores a retornar, ou ambos, podem ser omitidos. Se for omitido o <tt>valor se falso</tt> e não ocorrer um erro, é retornado o resultado da <tt>expressão</tt>.


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

Se também for omitido o <tt>valor se verdadeiro</tt> e ocorrer um erro, é retornada uma expressão vazia:


 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;  

#ifexpr
This function evaluates a mathematical expression and returns one of two strings depending on the boolean value of the result:


 * <tt> </tt>

The <tt>expression</tt> input is evaluated exactly as for <tt>#expr</tt> above, with the same operators being available. The output is then evaluated as a boolean expression. This function is equivalent to one using <tt>#ifeq</tt> and <tt>#expr</tt> only:


 * <tt> </tt>

An empty input expression evaluates to false:


 * <tt> </tt> &rarr; 

Either or both the return values may be omitted; no output is given when the appropriate branch is left empty:


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;  

#ifexist
This function takes an input string, interprets it as a page title, and returns one of two values depending on whether or not the page exists on the local wiki.


 * <tt> </tt>

The function evaluates to <tt>true</tt> if the page exists, whether it contains content, is visibly blank (contains meta-data such as category links or magic words, but no visible content), is blank, or is a redirect. Only pages that are redlinked evaluate to false, including if the page used to exist but has been deleted.


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

The function evaluates to true for system messages that have been customised, and for special pages that are defined by the software.


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr;
 * <tt> </tt> &rarr;

<tt>#ifexist:</tt> is considered an "expensive parser function", only a limited number of which can be included on any one page (including functions inside transcluded templates). When this limit is exceeded, the page is categorised into Category:, and any further <tt>#ifexist:</tt> functions automatically return false, whether the target page exists or not.

If a page checks a target using <tt>#ifexist:</tt>, then that page will appear in the list for the target page. So if the code <tt> </tt> were included live on this page, /Foo will list.

On wikis using a shared media repository, <tt>#ifexist:</tt> can be used to check if a file has been uploaded to the repository, but not to the wiki itself:
 * <tt> </tt>  &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

If a local description page has been created for the file, the result is exists for all of the above.

#rel2abs
This function converts a relative file path into an absolute filepath.


 * <tt> </tt>
 * <tt> </tt>

Within the <tt>path</tt> input, the following syntax is valid:
 * &rarr; the current level
 * &rarr; "go up one level"
 * &rarr; "go down one level into the subdirectory /foo"

If the <tt>base path</tt> is not specified, the full page name of the page will be used instead:


 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''

Invalid syntax, such as <tt>/.</tt> or <tt>/./</tt>, is ignored. Since no more than two consecutive full stops are permitted, sequences such as these can be used to separate successive statements:


 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''

#switch
This function compares one input value against several test cases, returning an associated string if a match is found.

The <tt>default result</tt> is returned if no <tt>case</tt> string matches the <tt>comparison string</tt>. In this syntax, the default result must be the last parameter and must not contain a raw equals sign. Alternatively, the default result may be explicitly declared with a case string of "<tt>#default</tt>"; default results declared in this way may be placed anywhere within the function:


 * <tt> </tt> &rarr; 

If the <tt>default</tt> parameter is omitted and no match is made, no content is added. It is possible to have 'fall through' values, where several <tt>case</tt> strings return the same <tt>result</tt> string. This minimises duplication.

Here cases 2, 3 and 4 all return <tt>result2</tt>; cases 6 and 7 both return <tt>result4</tt>

As with <tt>#ifeq</tt>, the comparison is made numerically if both the comparison string and the case string being tested are numeric; or as case-sensitive string otherwise. A <tt>case</tt> string may be empty:
 * <tt> </tt> &rarr; 

Once a match is found, subsequent <tt>cases</tt> are ignored:
 * <tt> </tt> &rarr; 

"Case" strings cannot contain raw equals signs. To work around this, create a template at = containing a single equals sign: <tt>=</tt> Then, use this template as follows:

<tt> </tt> &rarr; 

#time
This parser function takes a date and/or time construct and formats it according to the syntax given. A date/time object can be specified; the default is the value of the magic word <tt> </tt> – that is, the time the page was last rendered into HTML.


 * <tt> </tt>
 * <tt> </tt>

The list of accepted formatting codes is given in the table to the right. Any character in the formatting string that is not recognised is passed through unaltered. There are also two ways to escape characters within the formatting string: In addition, the digraph <tt>xx</tt> is interpreted as a single literal "x".
 * 1) A backslash followed by a formatting character is interpreted as a single literal character
 * 2) characters enclosed in double quotes are considered literal characters, and the quotes are removed


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

The <tt>date/time object</tt> can be in any format accepted by PHP's strtotime function. Both absolute (eg <tt>20 December 2000</tt>) and relative (eg <tt>+20 hours</tt>) times are accepted.

Full or partial absolute dates can be specified; the function will 'fill in' parts of the date that are not specified using the current values:


 * <tt> </tt> &rarr; '''

A four-digit number is interpreted as hours and minutes if possible, and otherwise as year:

<tt> </tt> &rarr; ''' Input is treated as a time rather than a year.

<tt> </tt> &rarr; ''' Since 19:60 is not a valid time, 1960 is treated as a year.

A six-digit number is interpreted as hours, minutes and seconds if possible, but otherwise as an error (not, for instance, a year and month):

<tt> </tt> &rarr; ''' Input is treated as a time rather than a year+month code.

<tt> </tt> &rarr; ''' Although 19:60:09 is not a valid time, 196009 is not interpreted as September 1960.

The function performs a certain amount of date mathematics:


 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''
 * <tt> </tt> &rarr; '''

#timel
This function is identical to <tt> </tt>, except that it uses the local time of the wiki (as set in ) when no date is given.


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

#titleparts
This function separates a pagetitle into segments based on slashes, then returns some of those segments as output.


 * <tt> </tt>

If the <tt>number of segments</tt> parameter is not specified, it defaults to "0", which returns all the segments. If the <tt>first segment</tt> parameter is not specified or is "0", it defaults to "1":


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

Negative values are accepted for both values. Negative values for <tt>number of segments</tt> effectively 'strips' segments from the end of the string. Negative values for <tt>first segment</tt> translates to "add this value to the total number of segments", loosely equivalent to "count from the right":


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr;  
 * <tt> </tt> &rarr;   Strips one segment from the end of the string, then returns the second segment and beyond

The string is split a maximum of 25 times; further slashes are ignored. The string is also limited to 255 characters, as it is treated as a page title:


 * <tt> </tt> &rarr; 

You can use #titleparts as a small "string parser & converter", but consider that it returns the first substring capitalized. If lower case is needed, use lc: function to control output.


 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 
 * <tt> </tt> &rarr; 

Substitution
Parser functions can be substituted by prefixing the hash character with <tt>subst:</tt>:


 * <tt> </tt> &rarr; the code <tt>    </tt> will be inserted in the wikitext since the page  exists.

Tables
Parser functions will mangle wikitable syntax, treating all the raw pipe characters as parameter divisors. To avoid this, most wikis create the template    :! with its contents only a raw pipe character. This 'hides' the pipe from the MediaWiki parser, ensuring that it is not considered until after all the templates and variables on a page have been expanded. Alternatively, raw HTML table syntax can be used, although this is less intuitive and more error-prone.

Stripping whitespace
Whitespace, including newlines, tabs, and spaces, is stripped from the beginning and end of all the parameters of these parser functions. If this is not desirable, adding any non-whitespace characters (including the HTML encoding for a whitespace character, invisible Unicode characters such as the zero-width space or direction marks, or sequences recognised and stripped by the MediaWiki parser such as <tt>  </tt>) will prevent further stripping:


 * &rarr; 


 * &rarr; 


 * &rarr; 

Ver também

 * :Palavras mágicas
 * :Funções do analisador sintáctico em predefinições