|
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| Line 1: |
Line 1: |
| --[[
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|
| |
|
| This module is intended to provide access to basic string functions.
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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
| |
| 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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|
| |
| This function returns a substring from the source string that matches a
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| specified pattern.
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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
| |
| 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
| |
| 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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|
| |
| If invoked using named parameters, Mediawiki will automatically remove any leading or
| |
| trailing whitespace from each string. In some circumstances this is desirable, in
| |
| other cases one may want to preserve the whitespace.
| |
|
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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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| * http://www.lua.org/manual/5.1/manual.html#5.4.1
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| * http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
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| * http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns
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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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|
| |
| If invoked using named parameters, Mediawiki will automatically remove any leading or
| |
| trailing whitespace from the target string. In some circumstances this is desirable, in
| |
| other cases one may want to preserve the whitespace.
| |
|
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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
| |
| 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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| ]]
| |
| function str.pos( frame )
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| local new_args = str._getParameters( frame.args, {'target', 'pos'} );
| |
| 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
| |
| 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
| |
| separatetly.
| |
| ]]
| |
| function str.str_find( frame )
| |
| local new_args = str._getParameters( frame.args, {'source', 'target'} );
| |
| local source_str = new_args['source'] or '';
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| local target_str = new_args['target'] or '';
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|
| |
| if target_str == '' then
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| return 1;
| |
| end
| |
|
| |
| local start = mw.ustring.find( source_str, target_str, 1, true )
| |
| if start == nil then
| |
| start = -1
| |
| end
| |
|
| |
| return start
| |
| end
| |
|
| |
| --[[
| |
| find
| |
|
| |
| This function allows one to search for a target string or pattern within another
| |
| string.
| |
|
| |
| 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}}
| |
|
| |
| Parameters
| |
| source: The string to search
| |
| target: The string or pattern to find within source
| |
| start: The index within the source string to start the search, defaults to 1
| |
| plain: Boolean flag indicating that target should be understood as plain
| |
| text and not as a Lua style regular expression, defaults to true
| |
|
| |
| If invoked using named parameters, Mediawiki will automatically remove any leading or
| |
| trailing whitespace from the parameter. In some circumstances this is desirable, in
| |
| other cases one may want to preserve the whitespace.
| |
|
| |
| This function returns the first index >= "start" where "target" can be found
| |
| within "source". Indices are 1-based. If "target" is not found, then this
| |
| function returns 0. If either "source" or "target" are missing / empty, this
| |
| function also returns 0.
| |
|
| |
| This function should be safe for UTF-8 strings.
| |
| ]]
| |
| function str.find( frame )
| |
| local new_args = str._getParameters( frame.args, {'source', 'target', 'start', 'plain' } );
| |
| local source_str = new_args['source'] or '';
| |
| local pattern = new_args['target'] or '';
| |
| local start_pos = tonumber(new_args['start']) or 1;
| |
| local plain = new_args['plain'] or true;
| |
|
| |
| if source_str == '' or pattern == '' then
| |
| return 0;
| |
| end
| |
|
| |
| plain = str._getBoolean( plain );
| |
|
| |
| local start = mw.ustring.find( source_str, pattern, start_pos, plain )
| |
| if start == nil then
| |
| start = 0
| |
| end
| |
|
| |
| return start
| |
| end
| |
|
| |
| --[[
| |
| replace
| |
|
| |
| This function allows one to replace a target string or pattern within another
| |
| string.
| |
|
| |
| Usage:
| |
| {{#invoke:String|replace|source_str|pattern_string|replace_string|replacement_count|plain_flag}}
| |
| OR
| |
| {{#invoke:String|replace|source=source_string|pattern=pattern_string|replace=replace_string|
| |
| count=replacement_count|plain=plain_flag}}
| |
|
| |
| Parameters
| |
| source: The string to search
| |
| pattern: The string or pattern to find within source
| |
| replace: The replacement text
| |
| count: The number of occurences to replace, defaults to all.
| |
| plain: Boolean flag indicating that pattern should be understood as plain
| |
| text and not as a Lua style regular expression, defaults to true
| |
| ]]
| |
| function str.replace( frame )
| |
| local new_args = str._getParameters( frame.args, {'source', 'pattern', 'replace', 'count', 'plain' } );
| |
| local source_str = new_args['source'] or '';
| |
| local pattern = new_args['pattern'] or '';
| |
| local replace = new_args['replace'] or '';
| |
| local count = tonumber( new_args['count'] );
| |
| local plain = new_args['plain'] or true;
| |
|
| |
| if source_str == '' or pattern == '' then
| |
| return source_str;
| |
| end
| |
| plain = str._getBoolean( plain );
| |
|
| |
| if plain then
| |
| pattern = str._escapePattern( pattern );
| |
| replace = mw.ustring.gsub( replace, "%%", "%%%%" ); --Only need to escape replacement sequences.
| |
| end
| |
|
| |
| local result;
| |
|
| |
| if count ~= nil then
| |
| result = mw.ustring.gsub( source_str, pattern, replace, count );
| |
| else
| |
| result = mw.ustring.gsub( source_str, pattern, replace );
| |
| end
| |
|
| |
| return result;
| |
| end
| |
|
| |
| --[[
| |
| simple function to pipe string.rep to templates.
| |
| ]]
| |
|
| |
| function str.rep( frame )
| |
| local repetitions = tonumber( frame.args[2] )
| |
| if not repetitions then
| |
| return str._error( 'function rep expects a number as second parameter, received "' .. ( frame.args[2] or '' ) .. '"' )
| |
| end
| |
| return string.rep( frame.args[1] or '', repetitions )
| |
| end
| |
|
| |
| --[[
| |
| Helper function that populates the argument list given that user may need to use a mix of
| |
| named and unnamed parameters. This is relevant because named parameters are not
| |
| identical to unnamed parameters due to string trimming, and when dealing with strings
| |
| we sometimes want to either preserve or remove that whitespace depending on the application.
| |
| ]]
| |
| function str._getParameters( frame_args, arg_list )
| |
| local new_args = {};
| |
| local index = 1;
| |
| local value;
| |
|
| |
| for i,arg in ipairs( arg_list ) do
| |
| value = frame_args[arg]
| |
| if value == nil then
| |
| value = frame_args[index];
| |
| index = index + 1;
| |
| end
| |
| new_args[arg] = value;
| |
| end
| |
|
| |
| return new_args;
| |
| end
| |
|
| |
| --[[
| |
| Helper function to handle error messages.
| |
| ]]
| |
| function str._error( error_str )
| |
| local frame = mw.getCurrentFrame();
| |
| local error_category = frame.args.error_category or 'Errors reported by Module String';
| |
| local ignore_errors = frame.args.ignore_errors or false;
| |
| local no_category = frame.args.no_category or false;
| |
|
| |
| if str._getBoolean(ignore_errors) then
| |
| return '';
| |
| end
| |
|
| |
| local error_str = '<strong class="error">String Module Error: ' .. error_str .. '</strong>';
| |
| if error_category ~= '' and not str._getBoolean( no_category ) then
| |
| error_str = '[[Category:' .. error_category .. ']]' .. error_str;
| |
| end
| |
|
| |
| return error_str;
| |
| end
| |
|
| |
| --[[
| |
| Helper Function to interpret boolean strings
| |
| ]]
| |
| function str._getBoolean( boolean_str )
| |
| local boolean_value;
| |
|
| |
| if type( boolean_str ) == 'string' then
| |
| boolean_str = boolean_str:lower();
| |
| if boolean_str == 'false' or boolean_str == 'no' or boolean_str == '0'
| |
| or boolean_str == '' then
| |
| boolean_value = false;
| |
| else
| |
| boolean_value = true;
| |
| end
| |
| elseif type( boolean_str ) == 'boolean' then
| |
| boolean_value = boolean_str;
| |
| else
| |
| error( 'No boolean value found' );
| |
| end
| |
| return boolean_value
| |
| end
| |
|
| |
| --[[
| |
| Helper function that escapes all pattern characters so that they will be treated
| |
| as plain text.
| |
| ]]
| |
| function str._escapePattern( pattern_str )
| |
| return mw.ustring.gsub( pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1" );
| |
| end
| |
|
| |
| return str
| |