Module:Escape/doc

Usage
This module is designed as an way to escape strings in a customized and efficient manner. It works by replacing characters that are preceded by your escape char (or phrase) There are two ways to call this module:

From another module: local esc = require('Module:Escape') esc:char local to_escape = esc:text local result = esc:undo(to_escape)

From a template:

In a template, the most useful function is kill.

This module is primarily intended to be used by other modules. However all functions can be called in template space using the function you want to call followed by arguments.

All module functions (i.e. any func. other than main) should be called using a colon, e.g. esc:char('%') or

{|class='wikitable' style='background:#fff' !style='vertical-align:top;width:7em'| !style='vertical-align:top;width:5em'| !style='vertical-align:top;width:5em'| !style='vertical-align:top'|
 * This function takes only one argument: A string. All characters in this string which are preceded by the sequence set by escape:char will be replaced with placeholders that can be converted back into that char by escape:undo
 * Takes two arguments:
 * 1) The string that may contain placeholders set by escape:text
 * 2) Optional, a char to be placed in front of any characters that have been de-escaped. (i.e. if you need to re-escape those string with a different char)
 * This is basically equivalent to calling string.gsub on the string returned by escape:text and feeding that result into escape:undo in a single step. Takes three arguments:
 * 1) A string
 * 2) A sequence of characters to be removed from that string. (May use a string.gsub pattern)
 * 3) Optional, a char to be placed in front of any characters that have been de-escaped.
 * This function's primary use is to initialize the patterns to scan a string for an escape/escaped sequence. It takes two arguments, the first being the escape character and the second being a table of arguments (optional). By default, this module will escape the \ char. To escape the {{code|{}} char instead, you can do {{code|require('Module:Escape'):char('{')}} (or {{code|esc:char('{')}} (presuming you stored the table returned by this module in the local variable esc).

When called without the second argument, char will return a table containing the functions. This allows, for example,  which would return '2'

For the most part, there is very little reason to set mode in template space since the patterns it stores are not shared with other invokations of this module. Templates should instead use the char if a new escape sequence is desired.

Shortcut (not fully implemented)
If provided a second argument that is a table containing a {key = value} pair, such that the key is text, undo, or kill and the value is a table containing the arguments that would have been passed to those functions. For example, escape:char('\\', {text = 'string'}) is equivalent to escape:char('\\'):text('string').

Currently, if multiple key-value pairs are provided, only one may execute. It was planned so that escape:char('\\', {text = 'string', undo = '='}) would be a shorthand for:

In the planned implementation, the text function would be called first, followed by undo or kill. (If both undo and kill are included as keys in the table, kill would be ignored.)


 * }

Caveats

 * When using a multi-character escape sequence, this module only marks it using the byte value of the first character. Thus, escape:undo will unescape, for example, all characters escaped with 'e' and 'esc' if both were used. In practice however this shouldn't be a problem as multiple escape sequences are pretty rare unless you're transitioning between multiple code languages. (Multiple multi-char escape sequences beginning with the same character are simply bad practice anyhow.)
 * Since byte values are stored as numbers, it is not recommended for you to use a number as an escape sequence (though it may work just fine).
 * Placeholder byte values separated with return ('\r') characters--chosen because they are seldom used at all, and virtually never used unpaired with '\n'; moreover, it is distinct from the markers generated by  or mw.text.nowiki (which use the delete char). To set a different separator char, include the key-value pair  in the table that you pass to escape:char.

Speed
The following are benchmarks...

when executing the following module function: 

when repeating the following line 500 times in a template:

0.767

All times in seconds. The module time x500 was calculated when you loaded this doc page (normally between 0.02 and 0.07). The template time x500 was recorded on Jan 15, 2015.

Module
Here's some sample output from the debug console below the module editor: {{#ifeq:{{SUBPAGENAME}}|sandbox | |

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