Module:String: Difference between revisions

--[[   

This module is intended to provide access to basic string functions.

Most of the functions provided here can be invoked with named parameters,  

unnamed parameters, or a mixture.  If named parameters are used, Mediawiki will  

Depending on the intended use, it may be advantageous to either preserve or

remove such whitespace.

Global options

     ignore_errors: If set to 'true' or 1, any error condition will result in  

         an empty string being returned rather than an error message.   

     error_category: If an error occurs, specifies the name of a category to  

         include with the error message.  The default category is   

         [Category:Errors reported by Module String].

     no_category: If set to 'true' or 1, no category will be added if an error

         is generated.

Unit tests for this module are available at Module:String/tests.

]]

local str = {}

--[[

len

This function returns the length of the target string.

Usage:

{{#invoke:String|len|target_string|}}

OR

{{#invoke:String|len|s=target_string}}

Parameters

     s: The string whose length to report

If invoked using named parameters, Mediawiki will automatically remove any leading or

trailing whitespace from the target string.   

     return mw.ustring.len( s )

end

--[[

sub

This function returns a substring of the target string at specified indices.

Usage:

{{#invoke:String|sub|target_string|start_index|end_index}}

OR

{{#invoke:String|sub|s=target_string|i=start_index|j=end_index}}

Parameters

     s: The string to return a subset of

     i: The fist index of the substring to return, defaults to 1.

     j: The last index of the string to return, defaults to the last character.

The first character of the string is assigned an index of 1.  If either i or j

is a negative value, it is interpreted the same as selecting a character by  

counting from the end of the string.  Hence, a value of -1 is the same as  

selecting the last character of the string.

If the requested indices are out of range for the given string, an error is  

reported.

     local i = tonumber( new_args['i'] ) or 1;

     local j = tonumber( new_args['j'] ) or -1;

     local len = mw.ustring.len( s );

     -- Convert negatives for range checking