Module:String

local str = {}

function str.len( frame )

   return mw.ustring.len( frame.args.s )

end

function str.sub( frame )

   return mw.ustring.sub( frame.args.s, tonumber( frame.args.i ), tonumber( frame.args.j ) )

end

function str.sublength( frame )

   local i = tonumber( frame.args.i ) or 0
   local len = tonumber( frame.args.len )
   return mw.ustring.sub( frame.args.s, i + 1, len and ( i + len ) )

end

function str.match( frame )

   return mw.ustring.match( frame.args.s, frame.args.pattern, tonumber( frame.args.i ) )

end

--[====[ str_find

This function duplicates the behavior of Template:Str find, including all of its quirks. 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.

Returns the first index in "source" that is a match to "target". Indexing is 1-based, and the function returns -1 if the "target" string is not present in "source". Both strings have any leading or trailing whitespace removed before searching.

Important Note: If the "target" string is empty / missing, this function returns a value of "1", which is generally unexpected behavior, and must be accounted for separatetly. ]====] function str.str_find( frame )

   local source_str = frame.args.source or ;
   local target_str = frame.args.target or ;
   if target_str ==  then
       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.

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
       

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.

Both "source" and "target" will be trimmed so that any leading or trailing whitespace is removed prior to searching. This function should be safe for UTF-8 strings. ]====] function str.find( frame )

   local source_str = frame.args.source or ;
   local pattern = frame.args.target or ;
   local start_pos = tonumber(frame.args.start) or 1;
   local plain = frame.args.plain or true;
       
   if source_str ==  or pattern ==  then
       return 0;
   end    
   
   if type( plain ) == 'string' then
       plain = plain:lower();
       if plain == 'false' or plain == 'no' or plain == '0' then
           plain = false;
       else
           plain = true;
       end    
   end

   local start = mw.ustring.find( source_str, pattern, start_pos, plain )
   if start == nil then
       start = 0
   end
   
   return start

end return str