Extension:迴圈

MediaWiki扩展手册

Loops 发行状态： 稳定版
实现	解析器函数
描述	为执行循环提供解析器函数
作者	David M. Sledge Daniel Werner
最新版本	0.5.2 (2019-08-05)
MediaWiki	1.34+
PHP	5.6+
数据库更改	否
许可协议	GNU通用公眾授權條款2.0或更新版本
下載	下載扩展 Git [?]: 下载Git master 浏览存储库 (GitHub) 提交历史 存储库貢獻者 (GitHub) 代码复核 README RELEASE-NOTES
示例	sandbox.semantic-mediawiki.org
参数 $wgLoopsEnabledFunctions $wgLoopsCountLimit
使用的函数钩 ParserClearState ParserFirstCallInit ParserLimitReportPrepare
季度下載量	42 (Ranked 94th)
前往translatewiki.net翻譯Loops扩展
問題	开启的任务 · 报告错误

Loops扩展提供解析器函数 来执行循环。

目前，这个扩展由MGChecker基本维护。

用法

以下示例使用了Variables 扩展名，有些情况下也使用了ParserFunctions 扩展名。

#while

{{#while}} performs a loop (i.e. it repeatedly parses a given wiki markup block statement) so long as the condition mark-up evaluates to non-whitespace.

{{#while:
 | <condition text>
 | <block statement>
}}

示例

The wiki markup:

{{#vardefine: i | 0 }}{{#while:
 | {{#ifexpr: {{#var: i }} < 5 | true }}
 | <nowiki />
* {{#var: i }}{{#vardefine: i | {{#expr: {{#var: i }} + 1 }} }}
}}

produces the following:

• 0
• 1
• 2
• 3
• 4

{{#while}} can also be used in a template to simulate a numbered array. If the page "Template:Loops Test" contains

{{#vardefine: i | 0 }}{{#while:
 | {{{arg{{#var: i }} |}}}
 | <nowiki />
* {{{arg{{#var: i }} }}}{{#vardefine: i
   | {{#expr: {{#var: i }} + 1 }}
 }}
}}

then the wiki-markup

{{Loops Test
 |arg0=zero
 |arg1=one
 |arg2=two
 |arg3=three
 |arg4=four
}}

produces

• zero
• one
• two
• three
• four

It's important to note that whitespace, including newlines, tabs, and spaces, is stripped from the beginning and end of all the arguments of these parser functions. If this is not desirable, adding any non-whitespace characters (including the HTML encoding for a whitespace character  ) will prevent further stripping (hence the ‎<nowiki> tags in the above examples).

#dowhile

{{#dowhile}} performs exactly like {{#while}}, with the exception that the block statement is guaranteed to be parsed and displayed (if it results in displayable text) at least once. This is done before the condition text is evaluated.

#loop

{{#loop: <variable name>
 | <starting value>
 | <number of loops to be performed>
 | <wiki markup>
}}

{{#loop}} repeatedly parses and displays <wiki markup> a number of times equal to the absolute value of <number of loops to be performed>. <Starting value> is placed in a variable (accessible by Variables extension's {{#var:}} parser function) using the name <variable name>. After each loop, the variable is incremented by one if <number of loops to be performed> is positive, or decremented by one if <number of loops to be performed> is negative.

From all loop functions, #loop should have the best performance since there is no condition which has to be expanded and validated for each cycle.

Examples

The following code:

{{#loop: varname
 | 4
 | 4
 | <nowiki />
* This is round {{#var: varname }} and we have {{#expr: 7 - {{#var: varname }} }} more to go
}}

produces

• This is round 4 and we have 3 more to go
• This is round 5 and we have 2 more to go
• This is round 6 and we have 1 more to go
• This is round 7 and we have 0 more to go

#forargs (experimental)

{{#forargs}} is to be used in templates.

It takes arguments that are passed to the template and puts them in variables accessible by Variables extension's {{#var:}} parser function.

{{#forargs: <prefix>
 | <key>
 | <value>
 | <block statement>
}}

This function iterates through each argument whose name begins with <prefix>.

With each iteration it puts the argument name minus <prefix> into <key> as if calling {{#vardefine: <key> }}.

It then takes the value of the argument and puts it into <value> in a similar method.

The block statement is then expanded.

The block statement may contain {{#var: <key> }} and {{#var: <value> }} to access the stored arguments.

Example

If the page "Template:Loops Test" contains

{{#forargs: arg
 | key
 | value
 | <nowiki />
* {{#var: key }} = {{#var: value }}
}}

then the wiki markup

{{Loops Test
 | arg1=val1
 | spam=spammity
 | arg5=val5
 | argument=value
}}

produces

• 1 = val1
• 5 = val5
• ument = value

#fornumargs (experimental)

{{#fornumargs: <key>
 | <value>
 | <block statement>
}}

{{#fornumargs}} performs similarly to {{#forargs}} with two major differences: It doesn't take a prefix argument, and it only works on numbered arguments whether they're explicitly numbered,

{{Template
 | 1=one
 | 2=two
}}

or implicitly numbered.

{{Template
 | one
 | two
}}

Mixing these methods in a single template call may cause values to get overwritten, so be careful.

Examples

If "Template:Loops Test" is edited to contain:

{{#fornumargs: number
 | value
 | <nowiki />
* {{#var: number }} = {{#var: value }}
}}

then

{{Loops Test
  | Apricot
  | B = Bolognese
  | Caramel slice
  | 5 = Eclair
}}

will result in

• 1 = Apricot
• 2 = Caramel slice
• 5 = Eclair

Installation

Some of the parser functions provided by this extension require the ParserFunctions as well as the Variables extension to be installed first.

• 下载文件，并将解压后的Loops文件夹移动到extensions/目录中。
  开发者和代码贡献人员应从Git安装扩展，输入：cd extensions/
git clone https://gerrit.wikimedia.org/r/mediawiki/extensions/Loops
• 将下列代码放置在您的LocalSettings.php 的底部：

  wfLoadExtension( 'Loops' );
  

• Configure at your convenience
•  完成 – 在您的wiki上导航至Special:Version，以验证已成功安装扩展。

Configuration

These configuration variables have to be set in the LocalSettings.php file after the inclusion of this extension.

$egLoopsCountLimit

This parameter sets the maximum number of loops a page is allowed to perform (default 100). Setting it to -1 lets the loops run within the limits of phps environment. This parameter affects neither the {{#forargs:}} nor {{#fornumargs:}} parser functions.

$egLoopsEnabledFunctions

Configuration variable (array) to define which Loops functions should be enabled. By default, all functions are enabled if the Variables extension is installed as well. If the Variables extension is not installed, #loop, #forargs and #fornumargs will be disabled since they do not work without it being installed. To enable the #fornumargs and #forargs functions only, one can use:

$egLoopsEnabledFunctions = array_diff(
    $egLoopsEnabledFunctions, [
        'forargs', 'fornumargs'
        ]
    );

參見

• Extension:LoopFunctions - Another extension for loops
• Module:Loops