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| − | --[[
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| | | | |
| − | This module is intended to provide access to basic string functions.
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| − |
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| − | Most of the functions provided here can be invoked with named parameters,
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| − | unnamed parameters, or a mixture. If named parameters are used, Mediawiki will
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| − | automatically remove any leading or trailing whitespace from the parameter.
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| − | Depending on the intended use, it may be advantageous to either preserve or
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| − | remove such whitespace.
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| − |
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| − | Global options
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| − | ignore_errors: If set to 'true' or 1, any error condition will result in
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| − | an empty string being returned rather than an error message.
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| − |
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| − | error_category: If an error occurs, specifies the name of a category to
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| − | include with the error message. The default category is
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| − | [Category:Errors reported by Module String].
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| − |
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| − | no_category: If set to 'true' or 1, no category will be added if an error
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| − | is generated.
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| − |
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| − | Unit tests for this module are available at Module:String/tests.
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| − | ]]
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| − |
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| − | local str = {}
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| − |
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| − | --[[
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| − | len
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| − |
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| − | This function returns the length of the target string.
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| − |
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| − | Usage:
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| − | {{#invoke:String|len|target_string|}}
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| − | OR
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| − | {{#invoke:String|len|s=target_string}}
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| − |
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| − | Parameters
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| − | s: The string whose length to report
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| − |
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| − | If invoked using named parameters, Mediawiki will automatically remove any leading or
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| − | trailing whitespace from the target string.
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| − | ]]
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| − | function str.len( frame )
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| − | local new_args = str._getParameters( frame.args, {'s'} );
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| − | local s = new_args['s'] or '';
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| − | return mw.ustring.len( s )
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| − | end
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| − |
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| − | --[[
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| − | sub
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| − |
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| − | This function returns a substring of the target string at specified indices.
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| − |
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| − | Usage:
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| − | {{#invoke:String|sub|target_string|start_index|end_index}}
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| − | OR
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| − | {{#invoke:String|sub|s=target_string|i=start_index|j=end_index}}
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| − |
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| − | Parameters
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| − | s: The string to return a subset of
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| − | i: The fist index of the substring to return, defaults to 1.
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| − | j: The last index of the string to return, defaults to the last character.
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| − |
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| − | The first character of the string is assigned an index of 1. If either i or j
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| − | is a negative value, it is interpreted the same as selecting a character by
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| − | counting from the end of the string. Hence, a value of -1 is the same as
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| − | selecting the last character of the string.
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| − |
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| − | If the requested indices are out of range for the given string, an error is
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| − | reported.
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| − | ]]
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| − | function str.sub( frame )
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| − | local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } );
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| − | local s = new_args['s'] or '';
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| − | local i = tonumber( new_args['i'] ) or 1;
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| − | local j = tonumber( new_args['j'] ) or -1;
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| − |
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| − | local len = mw.ustring.len( s );
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| − |
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| − | -- Convert negatives for range checking
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| − | if i < 0 then
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| − | i = len + i + 1;
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| − | end
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| − | if j < 0 then
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| − | j = len + j + 1;
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| − | end
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| − |
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| − | if i > len or j > len or i < 1 or j < 1 then
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| − | return str._error( 'String subset index out of range' );
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| − | end
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| − | if j < i then
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| − | return str._error( 'String subset indices out of order' );
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| − | end
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| − |
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| − | return mw.ustring.sub( s, i, j )
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| − | end
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| − |
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| − | --[[
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| − | This function implements that features of {{str sub old}} and is kept in order
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| − | to maintain these older templates.
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| − | ]]
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| − | function str.sublength( frame )
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| − | local i = tonumber( frame.args.i ) or 0
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| − | local len = tonumber( frame.args.len )
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| − | return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) )
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| − | end
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| − |
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| − | --[[
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| − | match
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| − |
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| − | This function returns a substring from the source string that matches a
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| − | specified pattern.
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| − |
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| − | Usage:
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| − | {{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag|nomatch_output}}
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| − | OR
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| − | {{#invoke:String|match|s=source_string|pattern=pattern_string|start=start_index
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| − | |match=match_number|plain=plain_flag|nomatch=nomatch_output}}
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| − |
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| − | Parameters
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| − | s: The string to search
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| − | pattern: The pattern or string to find within the string
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| − | start: The index within the source string to start the search. The first
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| − | character of the string has index 1. Defaults to 1.
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| − | match: In some cases it may be possible to make multiple matches on a single
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| − | string. This specifies which match to return, where the first match is
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| − | match= 1. If a negative number is specified then a match is returned
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| − | counting from the last match. Hence match = -1 is the same as requesting
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| − | the last match. Defaults to 1.
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| − | plain: A flag indicating that the pattern should be understood as plain
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| − | text. Defaults to false.
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| − | nomatch: If no match is found, output the "nomatch" value rather than an error.
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| − |
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| − | If invoked using named parameters, Mediawiki will automatically remove any leading or
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| − | trailing whitespace from each string. In some circumstances this is desirable, in
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| − | other cases one may want to preserve the whitespace.
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| − |
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| − | If the match_number or start_index are out of range for the string being queried, then
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| − | this function generates an error. An error is also generated if no match is found.
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| − | If one adds the parameter ignore_errors=true, then the error will be suppressed and
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| − | an empty string will be returned on any failure.
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| − |
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| − | For information on constructing Lua patterns, a form of [regular expression], see:
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| − |
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| − | * https://www.lua.org/manual/5.1/manual.html#5.4.1
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| − | * https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
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| − | * https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns
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| − |
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| − | ]]
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| − | function str.match( frame )
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| − | local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} );
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| − | local s = new_args['s'] or '';
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| − | local start = tonumber( new_args['start'] ) or 1;
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| − | local plain_flag = str._getBoolean( new_args['plain'] or false );
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| − | local pattern = new_args['pattern'] or '';
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| − | local match_index = math.floor( tonumber(new_args['match']) or 1 );
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| − | local nomatch = new_args['nomatch'];
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| − |
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| − | if s == '' then
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| − | return str._error( 'Target string is empty' );
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| − | end
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| − | if pattern == '' then
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| − | return str._error( 'Pattern string is empty' );
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| − | end
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| − | if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then
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| − | return str._error( 'Requested start is out of range' );
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| − | end
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| − | if match_index == 0 then
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| − | return str._error( 'Match index is out of range' );
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| − | end
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| − | if plain_flag then
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| − | pattern = str._escapePattern( pattern );
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| − | end
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| − |
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| − | local result
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| − | if match_index == 1 then
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| − | -- Find first match is simple case
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| − | result = mw.ustring.match( s, pattern, start )
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| − | else
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| − | if start > 1 then
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| − | s = mw.ustring.sub( s, start );
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| − | end
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| − |
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| − | local iterator = mw.ustring.gmatch(s, pattern);
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| − | if match_index > 0 then
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| − | -- Forward search
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| − | for w in iterator do
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| − | match_index = match_index - 1;
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| − | if match_index == 0 then
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| − | result = w;
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| − | break;
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| − | end
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| − | end
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| − | else
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| − | -- Reverse search
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| − | local result_table = {};
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| − | local count = 1;
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| − | for w in iterator do
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| − | result_table[count] = w;
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| − | count = count + 1;
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| − | end
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| − |
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| − | result = result_table[ count + match_index ];
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| − | end
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| − | end
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| − |
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| − | if result == nil then
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| − | if nomatch == nil then
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| − | return str._error( 'Match not found' );
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| − | else
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| − | return nomatch;
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| − | end
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| − | else
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| − | return result;
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| − | end
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| − | end
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| − |
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| − | --[[
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| − | pos
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| − |
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| − | This function returns a single character from the target string at position pos.
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| − |
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| − | Usage:
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| − | {{#invoke:String|pos|target_string|index_value}}
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| − | OR
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| − | {{#invoke:String|pos|target=target_string|pos=index_value}}
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| − |
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| − | Parameters
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| − | target: The string to search
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| − | pos: The index for the character to return
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| − |
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| − | If invoked using named parameters, Mediawiki will automatically remove any leading or
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| − | trailing whitespace from the target string. In some circumstances this is desirable, in
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| − | other cases one may want to preserve the whitespace.
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| − |
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| − | The first character has an index value of 1.
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| − |
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| − | If one requests a negative value, this function will select a character by counting backwards
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| − | from the end of the string. In other words pos = -1 is the same as asking for the last character.
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| − |
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| − | A requested value of zero, or a value greater than the length of the string returns an error.
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| − | ]]
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| − | function str.pos( frame )
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| − | local new_args = str._getParameters( frame.args, {'target', 'pos'} );
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| − | local target_str = new_args['target'] or '';
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| − | local pos = tonumber( new_args['pos'] ) or 0;
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| − |
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| − | if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then
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| − | return str._error( 'String index out of range' );
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| − | end
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| − |
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| − | return mw.ustring.sub( target_str, pos, pos );
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| − | end
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| − |
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| − | --[[
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| − | str_find
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| − |
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| − | This function duplicates the behavior of {{str_find}}, including all of its quirks.
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| − | This is provided in order to support existing templates, but is NOT RECOMMENDED for
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| − | new code and templates. New code is recommended to use the "find" function instead.
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| − |
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| − | Returns the first index in "source" that is a match to "target". Indexing is 1-based,
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| − | and the function returns -1 if the "target" string is not present in "source".
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| − |
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| − | Important Note: If the "target" string is empty / missing, this function returns a
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| − | value of "1", which is generally unexpected behavior, and must be accounted for
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| − | separatetly.
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| − | ]]
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| − | function str.str_find( frame )
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| − | local new_args = str._getParameters( frame.args, {'source', 'target'} );
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| − | local source_str = new_args['source'] or '';
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| − | local target_str = new_args['target'] or '';
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| − |
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| − | if target_str == '' then
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| − | return 1;
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| − | end
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| − |
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| − | local start = mw.ustring.find( source_str, target_str, 1, true )
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| − | if start == nil then
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| − | start = -1
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| − | end
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| − |
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| − | return start
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| − | end
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| − |
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| − | --[[
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| − | find
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| − |
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| − | This function allows one to search for a target string or pattern within another
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| − | string.
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| − |
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| − | Usage:
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| − | {{#invoke:String|find|source_str|target_string|start_index|plain_flag}}
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| − | OR
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| − | {{#invoke:String|find|source=source_str|target=target_str|start=start_index|plain=plain_flag}}
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| − |
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| − | Parameters
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| − | source: The string to search
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| − | target: The string or pattern to find within source
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| − | start: The index within the source string to start the search, defaults to 1
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| − | plain: Boolean flag indicating that target should be understood as plain
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| − | text and not as a Lua style regular expression, defaults to true
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| − |
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| − | If invoked using named parameters, Mediawiki will automatically remove any leading or
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| − | trailing whitespace from the parameter. In some circumstances this is desirable, in
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| − | other cases one may want to preserve the whitespace.
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| − |
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| − | This function returns the first index >= "start" where "target" can be found
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| − | within "source". Indices are 1-based. If "target" is not found, then this
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| − | function returns 0. If either "source" or "target" are missing / empty, this
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| − | function also returns 0.
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| − |
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| − | This function should be safe for UTF-8 strings.
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| − | ]]
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| − | function str.find( frame )
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| − | local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } );
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| − | local source_str = new_args['source'] or '';
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| − | local pattern = new_args['target'] or '';
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| − | local start_pos = tonumber(new_args['start']) or 1;
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| − | local plain = new_args['plain'] or true;
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| − |
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| − | if source_str == '' or pattern == '' then
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| − | return 0;
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| − | end
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| − |
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| − | plain = str._getBoolean( plain );
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| − |
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| − | local start = mw.ustring.find( source_str, pattern, start_pos, plain )
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| − | if start == nil then
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| − | start = 0
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| − | end
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| − |
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| − | return start
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| − | end
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| − |
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| − | --[[
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| − | replace
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| − |
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| − | This function allows one to replace a target string or pattern within another
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| − | string.
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| − |
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| − | Usage:
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| − | {{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
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| − | OR
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| − | {{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string|
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| − | count=replacement_count|plain=plain_flag}}
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| − |
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| − | Parameters
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| − | source: The string to search
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| − | pattern: The string or pattern to find within source
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| − | replace: The replacement text
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| − | count: The number of occurences to replace, defaults to all.
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| − | plain: Boolean flag indicating that pattern should be understood as plain
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| − | text and not as a Lua style regular expression, defaults to true
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| − | ]]
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| − | function str.replace( frame )
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| − | local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } );
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| − | local source_str = new_args['source'] or '';
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| − | local pattern = new_args['pattern'] or '';
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| − | local replace = new_args['replace'] or '';
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| − | local count = tonumber( new_args['count'] );
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| − | local plain = new_args['plain'] or true;
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| − |
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| − | if source_str == '' or pattern == '' then
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| − | return source_str;
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| − | end
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| − | plain = str._getBoolean( plain );
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| − |
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| − | if plain then
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| − | pattern = str._escapePattern( pattern );
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| − | replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
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| − | end
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| − |
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| − | local result;
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| − |
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| − | if count ~= nil then
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| − | result = mw.ustring.gsub( source_str, pattern, replace, count );
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| − | else
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| − | result = mw.ustring.gsub( source_str, pattern, replace );
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| − | end
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| − |
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| − | return result;
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| − | end
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| − |
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| − | --[[
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| − | simple function to pipe string.rep to templates.
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| − | ]]
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| − |
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| − | function str.rep( frame )
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| − | local repetitions = tonumber( frame.args[2] )
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| − | if not repetitions then
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| − | return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
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| − | end
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| − | return string.rep( frame.args[1] or '', repetitions )
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| − | end
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| − |
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| − | --[[
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| − | Helper function that populates the argument list given that user may need to use a mix of
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| − | named and unnamed parameters. This is relevant because named parameters are not
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| − | identical to unnamed parameters due to string trimming, and when dealing with strings
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| − | we sometimes want to either preserve or remove that whitespace depending on the application.
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| − | ]]
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| − | function str._getParameters( frame_args, arg_list )
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| − | local new_args = {};
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| − | local index = 1;
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| − | local value;
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| − |
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| − | for i,arg in ipairs( arg_list ) do
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| − | value = frame_args[arg]
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| − | if value == nil then
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| − | value = frame_args[index];
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| − | index = index + 1;
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| − | end
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| − | new_args[arg] = value;
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| − | end
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| − |
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| − | return new_args;
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| − | end
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| − |
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| − | --[[
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| − | Helper function to handle error messages.
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| − | ]]
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| − | function str._error( error_str )
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| − | local frame = mw.getCurrentFrame();
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| − | local error_category = frame.args.error_category or 'Errors reported by Module String';
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| − | local ignore_errors = frame.args.ignore_errors or false;
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| − | local no_category = frame.args.no_category or false;
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| − |
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| − | if str._getBoolean(ignore_errors) then
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| − | return '';
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| − | end
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| − |
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| − | local error_str = '<strong class="error">String Module Error: ' .. error_str .. '</strong>';
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| − | if error_category ~= '' and not str._getBoolean( no_category ) then
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| − | error_str = '[[Category:' .. error_category .. ']]' .. error_str;
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| − | end
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| − |
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| − | return error_str;
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| − | end
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| − |
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| − | --[[
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| − | Helper Function to interpret boolean strings
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| − | ]]
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| − | function str._getBoolean( boolean_str )
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| − | local boolean_value;
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| − |
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| − | if type( boolean_str ) == 'string' then
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| − | boolean_str = boolean_str:lower();
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| − | if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'
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| − | or boolean_str == '' then
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| − | boolean_value = false;
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| − | else
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| − | boolean_value = true;
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| − | end
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| − | elseif type( boolean_str ) == 'boolean' then
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| − | boolean_value = boolean_str;
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| − | else
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| − | error( 'No boolean value found' );
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| − | end
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| − | return boolean_value
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| − | end
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| − |
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| − | --[[
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| − | Helper function that escapes all pattern characters so that they will be treated
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| − | as plain text.
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| − | ]]
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| − | function str._escapePattern( pattern_str )
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| − | return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
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| − | end
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| − |
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| − | return str
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