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Module:String

3,847 bytes added, 13:29, 25 February 2013
adds updated match support with wider parameter choices, whitespace handling, etc.
end
--[[
This function implements that features of {{str sub old}} and is kept in order
to maintain these older templates.
]]
function str.sublength( frame )
local i = tonumber( frame.args.i ) or 0
end
--[[
match
 
This function returns a substring from the source string that matches a
specified pattern.
 
Usage:
{{#invoke:String|match|source_string|pattern_string|start_index|match_number|plain_flag}}
OR
{{#invoke:String|pos|s=source_string|pattern=pattern_string|start=start_index
|match=match_number|plain=plain_flag}}
 
Parameters
s: The string to search
pattern: The pattern or string to find within the string
start: The index within the source string to start the search. The first
character of the string has index 1. Defaults to 1.
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
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
the last match. Defaults to 1.
plain_flag: A flag indicating that the pattern should be understood as plain
text. Defaults to false.
 
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.
 
If the match_number or start_index are out of range for the string being queried, then
this function generates an error. An error is also generated if no match is found.
If one adds the parameter ignore_errors=true, then the error will be suppressed and
an empty string will be returned on any failure.
 
For information on constructing Lua patterns, a form of [regular expression], see:
 
* http://www.lua.org/manual/5.1/manual.html#5.4.1
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns
* http://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Ustring_patterns
 
]]
function str.match( frame )
local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain'} ); local s = new_args['s'] or ''; local start = tonumber( new_args['start'] ) or 1; local plain_flag = str._getBoolean( new_args['plain'] or false ); local pattern = new_args['pattern'] or ''; local match_index = math.floor( tonumber(new_args['match']) or 1 ); if s == '' then return str._error( 'Target string is empty' ); end if pattern == '' then return str._error( 'Pattern string is empty' ); end if math.abs(start) < 1 or math.abs(start) > mw.ustring.len( s ) then return str._error( 'Requested start is out of range' ); end if match_index == 0 then return str._error( 'Match index is out of range' ); end if plain_flag then pattern = str._escapePattern( pattern ); end local result if match_index == 1 then -- Find first match( frameis simple case result = mw.argsustring.match( s, framepattern, start ) else if start > 1 then s = mw.argsustring.patternsub( s, tonumber( framestart ); end local iterator = mw.argsustring.i gmatch(s, pattern) ; if match_index > 0 then -- Forward search for w in iterator do match_index = match_index - 1; if match_index == 0 then result = w; break; end end else -- Reverse search local result_table = {}; local count = 1; for w in iterator do result_table[count] = w; count = count + 1; end result = result_table[ count + match_index ]; end end if result == nil then return str._error( 'Match not found' ); else return result; end
end
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