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Module:String

6,902 bytes added, 11:39, 12 September 2020
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--[[
This module is intended to provide access to basic string functions.
Most of the functions provided here can be invoked with named parameters, unnamed parameters, or a mixture. If named parameters are used, Mediawiki will automatically remove any leading or trailing whitespace from the parameter.
Depending on the intended use, it may be advantageous to either preserve or
remove such whitespace.
Global options
ignore_errors: If set to 'true' or 1, any error condition will result in an empty string being returned rather than an error message. error_category: If an error occurs, specifies the name of a category to include with the error message. The default category is
[Category:Errors reported by Module String].
no_category: If set to 'true' or 1, no category will be added if an error
is generated.
 
Unit tests for this module are available at Module:String/tests.
]]
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
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 );
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 {{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 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. It is exported for use in other modules
 
Usage:
strmatch = require("Module:String")._match
sresult = strmatch( s, pattern, start, match, plain, nomatch )
 
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.
 
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
 
]]
-- This sub-routine is exported for use in other modules
function str._match( s, pattern, start, match_index, plain_flag, nomatch )
if s == '' then
return str._error( 'Target string is empty' )
end
if pattern == '' then
return str._error( 'Pattern string is empty' )
end
start = tonumber(start) or 1
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
 
--[[
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|nomatch_output}}
OR
{{#invoke:String|match|s=source_string|pattern=pattern_string|start=start_index
|match=match_number|plain=plain_flag|nomatch=nomatch_output}}
 
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
 
]]
-- This is the entry point for #invoke:String|match
function str.match( frame )
return mw local new_args = str.ustring.match_getParameters( frame.args., {'s', frame.args.'pattern', 'start', 'match', 'plain', 'nomatch'} ) local s = new_args['s'] or '' local start = tonumber( framenew_args['start'] ) or 1 local plain_flag = str.args_getBoolean( new_args['plain'] or false ) local pattern = new_args['pattern'] or '' local match_index = math.i floor( tonumber(new_args['match']) or 1 ) local nomatch = new_args['nomatch']  return str._match( s, pattern, start, match_index, plain_flag, nomatch )
end
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.
]]
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
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
This function duplicates the behavior of {{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.
]]
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
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
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.
]]
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
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 resultend --[[ 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
if plain then--[[ pattern = str._escapePattern( pattern ); replace = str._escapePattern( replace ); end local result;escapePattern
if count ~= nil then result = mw.ustringThis function escapes special characters from a Lua string pattern.gsub( source_str, pattern, replace, count ); elseSee [1] result = mw.ustringfor details on how patterns work.gsub( source_str, pattern, replace ); end
[1] https://www.mediawiki.org/wiki/Extension:Scribunto/Lua_reference_manual#Patterns Usage:{{#invoke:String|escapePattern|pattern_string}} Parameters pattern_string: The pattern string to escape.]]function str.escapePattern( frame ) local pattern_str = frame.args[1] if not pattern_str then return str._error( 'No pattern string specified' ) end local result= str._escapePattern( pattern_str ) return resultend --[[countThis function counts the number of occurrences of one string in another.]]function str.count(frame) local args = str._getParameters(frame.args, {'source', 'pattern', 'plain'}) local source = args.source or '' local pattern = args.pattern or '' local plain = str._getBoolean(args.plain or true) if plain then pattern = str._escapePattern(pattern) end local _, count = mw.ustring.gsub(source, pattern, '') return countend --[[endswithThis function determines whether a string ends with another string.]]function str.endswith(frame) local args = str._getParameters(frame.args, {'source', 'pattern'}) local source = args.source or '' local pattern = args.pattern or '' if pattern == '' then -- All strings end with the empty string. return "yes" end if mw.ustring.sub(source, -mw.ustring.len(pattern), -1) == pattern then return "yes" else return "" endend --[[join Join all non empty arguments together;the first argument is the separator.Usage:{{#invoke:String|join|sep|one|two|three}}]]function str.join(frame) local args = {} local sep for _, v in ipairs( frame.args ) do if sep then if v ~= '' then table.insert(args, v) end else sep = v end end return table.concat( args, sep or '' )
end
]]
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
--[[
]]
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
]]
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

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