Module:String

local str = {}

-- len function str.len( frame ) local new_args = str._getParameters( frame.args, {'s'} ); local s = new_args['s'] or ''; return mw.ustring.len( s ) end

-- sub function str.sub( frame ) local new_args = str._getParameters( frame.args, { 's', 'i', 'j' } ); local s = new_args['s'] or ''; local i = tonumber( new_args['i'] ) or 1; local j = tonumber( new_args['j'] ) or -1; 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 if i > len or j > len or i < 1 or j < 1 then return str._error( 'String subset index out of range' ); end if j < i then return str._error( 'String subset indices out of order' ); end return mw.ustring.sub( s, i, j ) end

-- This function implements that features of and is kept in order to maintain these older templates. 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

-- match function str.match( frame ) local new_args = str._getParameters( frame.args, {'s', 'pattern', 'start', 'match', 'plain', 'nomatch'} ); 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 ); local nomatch = new_args['nomatch']; 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 is simple case result = mw.ustring.match( s, pattern, start ) else if start > 1 then s = mw.ustring.sub( s, start ); end local iterator = mw.ustring.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 if nomatch == nil then return str._error( 'Match not found' ); else return nomatch; end else return result; end end

-- pos function str.pos( frame ) local new_args = str._getParameters( frame.args, {'target', 'pos'} ); local target_str = new_args['target'] or ''; local pos = tonumber( new_args['pos'] ) or 0;

if pos == 0 or math.abs(pos) > mw.ustring.len( target_str ) then return str._error( 'String index out of range' ); end return mw.ustring.sub( target_str, pos, pos ); end

-- str_find function str.str_find( frame ) local new_args = str._getParameters( frame.args, {'source', 'target'} ); local source_str = new_args['source'] or ''; local target_str = new_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 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 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 = ' String Module Error: ' .. error_str .. ' ';   if error_category ~= '' and not str._getBoolean( no_category ) then error_str = '' .. 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