Module:Ustring
 | This Lua module is used in system messages, and on approximately 732,000 pages, or roughly 1% of all pages. Changes to it can cause immediate changes to the Wikipedia user interface. To avoid major disruption and server load, any changes should be tested in the module's /sandbox or /testcases subpages, or in your own module sandbox. The tested changes can be added to this page in a single edit. Please discuss changes on the talk page before implementing them. |
 | This module is rated as ready for general use. It has reached a mature form and is thought to be relatively bug-free and ready for use wherever appropriate. It is ready to mention on help pages and other Wikipedia resources as an option for new users to learn. To reduce server load and bad output, it should be improved by sandbox testing rather than repeated trial-and-error editing. |
This module directly imports all functions from the mw.ustring library. Documentation for each function can be found there.
The module takes an indefinite number of arguments. Arguments given as |s1=, |s2=, etc, are read first, and are used as strings. All remaining numerical arguments are coerced to number type if possible, and remain strings if not. If you wish for a numerical (i.e. unnamed or "|1=", "|2=") to remain a string, you can simply escape it by inserting \ at the beginning of the string.
Note that MediaWiki will always trim whitespace from named arguments; to give arguments with surrounding whitespace you must use unnamed parameters starting with \.
You can also wrap results in tags. All other unused arguments will be passed to
frame:extensionTag
UsageUsage
{{#invoke:Ustring|function_name|arg1|arg2|...}} is equivalent to mw.ustring.function_name
( arg1, arg2, ... )
Example using mw.ustring.subExample using mw.ustring.sub
{{#invoke:Ustring|sub|s1=abcde|2|4}}
produces:
bcd
Example using mw.ustring.gsubExample using mw.ustring.gsub
{{#invoke:Ustring|gsub|s1=1234|23|}}
produces:
14
Example using mw.ustring.charExample using mw.ustring.char
&#{{#invoke:ustring|char|49|48|59}}
produces:
Example using mw.ustring.matchExample using mw.ustring.match
{{#invoke:Ustring|match|s1=abcde|s2=(c%w)}}
produces:
cd
Note: Only the first match is returned. Additional returns are omitted because mw.ustring.gsub's second return value is generally undesirable.
Example using tag argumentsExample using tag arguments
{{#invoke:Ustring|match
|s1={{Module:Ustring}}|%s%s%sif%snot%s[^%s]+%sthen.+%
<!--enter an actual newline character to match '\n'-->%s%s%send
|tag=syntaxhighlight|lang=lua}}
produces:
if not fargs.tag then
return (what(unpack(args))) -- Outside parens truncate to first result avoiding tail call
end
local tagargs = {}
for x, y in pairs(fargs) do
if not fargsused[x] then tagargs[x] = y end
end
Note that:
<syntaxhighlight lang="lua">{{#invoke:Ustring|match
|s1={{Module:Ustring}}|%s%s%sif%snot%s[^%s]+%sthen.+%
<!--enter an actual newline character to match '\n'-->%s%s%send}}</syntaxhighlight>
produces:
{{#invoke:Ustring|match
|s1={{Module:Ustring}}|%s%s%sif%snot%s[^%s]+%sthen.+%
<!--enter an actual newline character to match '\n'-->%s%s%send}}
ErrorsErrors
Errors from accessing mw.ustring should be maintained, e.g.:
{{#invoke:Ustring|xyzzy}}
should produce:
Script error: The function "xyzzy" does not exist.
and
{{#invoke:Ustring|maxPatternLength}}
should produce:
Script error: "maxPatternLength" is not a function.
See alsoSee also
require('strict')
return setmetatable({}, {
__index = function(t, k)
local what = mw.ustring[k]
if type(what) ~= "function" then
return what
end
return function(frame)
local fargs = frame.args
local fargsused = { tag = true }
local args = {}
local str_i = 1
while fargs['s' .. str_i] do
fargsused['s' .. str_i] = true
args[str_i] = fargs['s' .. str_i]
str_i = str_i + 1
end
for i, v in ipairs(fargs) do
fargsused[i] = true
args[i + str_i - 1] = tonumber(v) or v:gsub("^\\", "", 1)
end
if not fargs.tag then
return (what(unpack(args))) -- Outside parens truncate to first result avoiding tail call
end
local tagargs = {}
for x, y in pairs(fargs) do
if not fargsused[x] then tagargs[x] = y end
end
return frame:extensionTag{name = fargs.tag, content = what(unpack(args)), args = tagargs}
end
end
})