Module:String

local str = {}

-- Cannot include null byte. local UTF8_char = "[\1-\127\194-\244][\128-\191]*"

--[[ ulen

Counts UTF-8 characters. Faster than mw.ustring.len.

Assumes that the encoding is correct. Unlike mw.ustring.len, does not return nil if encoding is invalid.

Does not count the bytes 192, 193, and 245-255. They are not used in UTF-8 and will not occur if the string is valid. They are replaced with the replacement character (U+FFFD) on MediaWiki pages. --]] function str.ulen(text) local _, length = string.gsub(text, UTF8_char, "") return length end

--[[ len

This function returns the length of the target string.

Usage: 13 OR 13

Parameters

   s: The string whose length to report

If invoked using named parameters, Mediawiki will automatically remove any leading or trailing whitespace from the target string. ]] 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

This function returns a substring of the target string at specified indices.

Usage: target_string OR target_string

Parameters

   s: The string to return a subset of
   i: The fist index of the substring to return, defaults to 1.
   j: The last index of the string to return, defaults to the last character.
   

The first character of the string is assigned an index of 1. If either i or j is a negative value, it is interpreted the same as selecting a character by counting from the end of the string. Hence, a value of -1 is the same as selecting the last character of the string.

If the requested indices are out of range for the given string, an error is reported. ]] 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

This function returns a substring from the source string that matches a specified pattern.

Usage: nomatch_output OR

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: A flag indicating that the pattern should be understood as plain
       text.  Defaults to false.
   nomatch: If no match is found, output the "nomatch" value rather than an error.

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', '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.pattern_escape(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

This function returns a single character from the target string at position pos.

Usage: OR

Parameters

   target: The string to search
   pos: The index for the character to return

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.

The first character has an index value of 1.

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.

A requested value of zero, or a value greater than the length of the string returns an error. ]] 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

This function duplicates the behavior of 1, 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".

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 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

This function allows one to search for a target string or pattern within another string.

Usage:

OR

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 an empty string. If either "source" or "target" are missing / empty, this function also returns an empty string.

This function should be safe for UTF-8 strings. ]] function str.find(frame) local params = { [1] = { required = true }, [2] = { required = true }, [3] = { type = "number" }, [4] = { type = "boolean" }, }

local args = require("Module:parameters").process(frame.args, params)

return mw.ustring.find(args[1], args[2], args[3], args[4]) end

--[[ replace

This function allows one to replace a target string or pattern within another string.

Usage: source_str OR source_string

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.pattern_escape(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

function str.gsub(frame) local params = { [1] = { required = true, allow_empty = true }, [2] = { required = true, allow_empty = true }, [3] = { required = true, allow_empty = true }, [4] = { type = "number" }, }

local args = require("Module:parameters").process(frame.args, params)

return (mw.ustring.gsub(args[1], args[2], args[3], args[4])) 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

function str.lower(frame) local text = frame.args[1] or return mw.ustring.lower(text) end

str.lc = str.lower

--[[ 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 _, 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 = ''; 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.pattern_escape(pattern_str) local invoked = false

if type(pattern_str) == "table" then if pattern_str.args then local frame = pattern_str invoked = true

if frame.args[1] then pattern_str = frame.args[1] else pattern_str = frame:getParent().args[1] end else error("First argument to pattern_escape should be a string, a number, or a frame object.") end elseif not (type(pattern_str) == "string" or type(pattern_str) == "number") then error("First argument to pattern_escape should be a string or a number.") end

if invoked then local escaped = mw.ustring.gsub(pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1") return escaped else return mw.ustring.gsub(pattern_str, "([%(%)%.%%%+%-%*%?%[%^%$%]])", "%%%1"); end end

function str.count(text, pattern, plain) if not (type(text) == "string" or type(text) == "number") then error('The first argument to the function "count" must be a string or a number, not a ' .. type(text) .. '.') end

if not (type(pattern) == "string" or type(pattern) == "number") then error('The first argument to the function "count" must be a string or a number, not a ' .. type(text) .. '.') end

if plain then pattern = str.pattern_escape(pattern) end

local _, count = mw.ustring.gsub(text, pattern, "")

return count end

function str.plain_gsub(text, pattern, replacement) local invoked = false

if type(text) == "table" then invoked = true

if text.args then local frame = text

local params = { [1] = {}, [2] = {}, [3] = { allow_empty = true }, }

local args = require("Module:parameters").process(frame.args, params)

text = args[1] pattern = args[2] replacement = args[3] else error("If the first argument to plain_gsub is a table, it should be a frame object.") end else if not (type(pattern) == "string" or type(pattern) == "number") then error("The second argument to plain_gsub should be a string or a number.") end

if not (type(replacement) == "string" or type(replacement) == "number") then error("The third argument to plain_gsub should be a string or a number.") end end

pattern = str.pattern_escape(pattern)

if invoked then text = mw.ustring.gsub(text, pattern, replacement) return text else return mw.ustring.gsub(text, pattern, replacement) end end

function str.matchToArray(text, pattern) local invoked = false

if type(text) == "table" then invoked = true

if text.args then local frame = text

local params = { [1] = { required = true }, [2] = { required = true }, }

local args = require("Module:parameters").process(frame.args, params)

text = args[1] pattern = args[2] else error("If the first argument to plain_gsub is a table, it should be a frame object.") end else if not (type(pattern) == "string" or type(pattern) == "number") then error("The second argument to plain_gsub should be a string or a number.") end end

local matches = {} local i = 0 for match in mw.ustring.gmatch(text, pattern) do i = i + 1 matches[i] = match end

if i > 0 then if invoked then return table.concat(matches, ", ") else return matches end else if invoked then return "" else return nil end end end

--[=[ Similar to gmatch, but it returns the count of the match in addition to the list of captures, something like ipairs().

If the pattern doesn't contain any captures, the whole match is returned.

Invoke thus:

for i, whole_match in require("Module:string").imatch(text, pattern) do [ do something with i and whole_match ] end

or

for i, capture1[, capture2[, capture3[, ...]]] in require("Module:string").imatch(text, pattern) do [ do something with i and capture1 ] end

For example, this code for i, whole_match in require("Module:string").imatch("a b c", "[a-z]") do mw.log(i, whole_match) end will log 1 a 2 b 3 c ]=] function str.imatch(text, pattern, pos, plain, use_basic_Lua_function) local i = 0 pos = pos or 0 if not string.find(pattern, "%b()") then pattern = "(" .. pattern .. ")" end local find = use_basic_Lua_function and string.find or mw.ustring.find return function() i = i + 1 local return_values = { find(text, pattern, pos, plain) } local j = return_values[2]

if return_values[3] then pos = j + 1 -- Skip the first two returned values, which are the indices of the -- whole match. return i, unpack(return_values, 3) end end end

function str.escapebytes(s) return (string.gsub(s, '.', function(char) return ('\\%03d'):format(string.byte(char)) end)) end

function str.URIdecode(frame) return mw.uri.decode(frame.args[1], frame.args[2] or "PATH") end

return str