Module:String: Difference between revisions

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    --[[
    --[[


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


    Most of the functions provided here can be invoked with named parameters,  
    Most of the functions provided here can be invoked with named parameters,
    unnamed parameters, or a mixture.  If named parameters are used, Mediawiki will  
    unnamed parameters, or a mixture.  If named parameters are used, Mediawiki will
    automatically remove any leading or trailing whitespace from the parameter.
    automatically remove any leading or trailing whitespace from the parameter.
    Depending on the intended use, it may be advantageous to either preserve or
    Depending on the intended use, it may be advantageous to either preserve or
    remove such whitespace.
    remove such whitespace.


    Global options
    Global options
         ignore_errors: If set to 'true' or 1, any error condition will result in  
         ignore_errors: If set to 'true' or 1, any error condition will result in
             an empty string being returned rather than an error message.
             an empty string being returned rather than an error message.
           
     
         error_category: If an error occurs, specifies the name of a category to  
         error_category: If an error occurs, specifies the name of a category to
             include with the error message.  The default category is
             include with the error message.  The default category is
             [Category:Errors reported by Module String].
             [Category:Errors reported by Module String].
           
     
         no_category: If set to 'true' or 1, no category will be added if an error
         no_category: If set to 'true' or 1, no category will be added if an error
             is generated.
             is generated.
           
     
    Unit tests for this module are available at Module:String/tests.
    Unit tests for this module are available at Module:String/tests.
    ]]
    ]]
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    If invoked using named parameters, Mediawiki will automatically remove any leading or
    If invoked using named parameters, Mediawiki will automatically remove any leading or
    trailing whitespace from the target string.
    trailing whitespace from the target string.
    ]]
    ]]
    function str.len( frame )
    function str.len( frame )
        local new_args = str._getParameters( frame.args, {'s'} );
    local new_args = str._getParameters( frame.args, {'s'} );
        local s = new_args['s'] or '';
    local s = new_args['s'] or '';
        return mw.ustring.len( s )
    return mw.ustring.len( s )
    end
    end


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         i: The fist index of the substring to return, defaults to 1.
         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.
         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
    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  
    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  
    counting from the end of the string.  Hence, a value of -1 is the same as
    selecting the last character of the string.
    selecting the last character of the string.


    If the requested indices are out of range for the given string, an error is  
    If the requested indices are out of range for the given string, an error is
    reported.
    reported.
    ]]
    ]]
    function str.sub( frame )
    function str.sub( frame )
        local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
    local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
        local s = new_args['s'] or '';
    local s = new_args['s'] or '';
        local i = tonumber( new_args['i'] ) or 1;
    local i = tonumber( new_args['i'] ) or 1;
        local j = tonumber( new_args['j'] ) or -1;
    local j = tonumber( new_args['j'] ) or -1;
       
     
        local len = mw.ustring.len( s );
    local len = mw.ustring.len( s );
     
    -- Convert negatives for range checking
    if i < 0 then
    i = len + i + 1;
    end
    if j < 0 then
    j = len + j + 1;
    end


        -- Convert negatives for range checking
    if i > len or j > len or i < 1 or j < 1 then
        if i < 0 then
    return str._error( 'String subset index out of range' );
            i = len + i + 1;
    end
        end
    if j < i then
        if j < 0 then
    return str._error( 'String subset indices out of order' );
            j = len + j + 1;
    end
        end
     </