Extension:Variables/es

La extensión Variables permite definir una variable en una página, usarla más tarde en esa misma página o en las plantillas incluidas, cambiar su valor, posiblemente a un valor dado por una expresión en términos del valor anterior, etc.

Semejante a una plantilla, aunque más ligero y su alcance es una página. Te permite emplear múltiples variables en una página sin impactar el desempeño de la wiki, como sucede cuando se maneja un gran número de plantillas. Combina esta extensión con la extensión ParserFunctions para mejores resultados.

Asigna el valor valorespecificado a la variable (que ya existe o se introduce) nombredelavariable.


 * Ejemplo:  haciendo anchodelicono = 25

Funciona exactamente como #vardefine, pero el valor afectado se imprime.


 * Ejemplo: making iconwidth = 

El valor de la variable nombredelavariable se produce por Si no definido, esto produce una cadena vacía; no da una mensaje de error.

Es posible definir un valor para el caso que la variable no está definido o está nula:



Esto es equivalente a:

pero es mucho más corto y mejor organizado. Aunque antes de versión 2.0, el valor predeterminado siempre estaba expandido. Desde version 2.0, el valor predeterminado solamente está expandido si realmente se usa.

El valor puede usarse en funciones del analizador, etc.


 * returns 1 if the variable is already defined. If the variable is not defined the return value is void.

It supports a second and a third parameter to replace these values.

This is equivalent to:

but it is much shorter and better arranged. Before version 2.5 though, both were always expanded. From version 2.5 on the if and else values only get expanded when their cases are actually entered.

Experimental new function introduced in Variables 2.0. This function will output the final, last value a variable has at the end of the page rendering. Naturally, the value will be inserted after the parser went over the entire wiki markup, so this function can't be used in other functions, expecting the right value is being used. Example:

The default value will be used if the variable doesn't exist at the final page rendering stage or if its value is an empty string. The default will be expanded right where the function is used, so the parameter will be expanded, even if it won't be needed.

Ejemplos
The ParserFunctions extension must also be installed to use #expr.

Compute : Agregar uno a n:

Configuration
This extension provides two configuration parameters:
 * Allows to disable the parser frame being marked as volatile by the extension, i.e. disable template caching.
 * Default:
 * Default:


 * Allows to disable specified parser functions provided by this textension.
 * Default:
 * Example:
 * Example:

Compatibility
The recommended version of the Variables extension for recent MediaWiki releases is listed below. Older versions of the extensions might work as well, but aren't tested for new MediaWiki releases.

Alternatives
As this extension will not be enabled for wikis run by the Wikimedia Foundation (WMF)  , here are some alternatives:


 * If you use Variables as cache for expensive operations, you can transform the section where you need them into a template and pass the required information as template parameters instead. This will work until you reach the expansion depth limit.
 * If you use Variables to do more complex template operations than possible with simple ParserFunctions, you can use Scribunto's Lua functionality instead. Note that this does not add support for global Variables. However, Extension:VariablesLua adds a Scribunto interface for the Variables store.
 * Don't use variables, instead duplicate the information you need as a variable. If that information is aquired by an expensive template call, performance may suffer. This will work until you reach the node count limit.

Véase también

 * Extension:MyVariables - Creates new variables in the MediaWiki sense
 * Extension:Loops - Provides parser functions for performing loops
 * Extension:Arrays - Create an array and provide array functions (such as search, split, and sort) and set operations (such as intersect, union and diff)
 * Extension:HashTables - New parser functions for handling hash tables in MediaWiki
 * Extension:HashTables - New parser functions for handling hash tables in MediaWiki