Module:WLink

WLink – Module with functions for strings in context of wikilinks and external links (URL). This module was imported from de:Module:WLink.

Usage

All functions expect exactly one unnamed parameter (which should be provided to get a meaningful answer). Whitespace ahead and after content is ignored. HTML Entities would not disturb syntax and might be resolved. The parameter might contain single or double bracketed links which would be extracted if appropriate. The return value is an empty string (“nothing”), if the parameter value does not fulfil the expectations. If there is a result or the query condition is true, at least one visible character will be returned. The result does not begin or end with a space.

ansiPercent

Convert string by ANSI encoding rather than UTF-8 encoding

Required for some 20^th century servers

Optional parameter space – encoding of spaces:

• space=+ – common for query components
• space=_ – as for Wikis
• Default: %20

formatURL

Create bracketed link, if not yet, from URL or domain

• [http://example.org/about Homepage] yields [http://example.org/about Homepage]
• http://example.org/about yields [http://example.org/about example.org/about]
• example.org yields [http://example.org/ example.org]

getArticleBase

Retrieve generic page title, no fragment nor brackets

Use current page title, if omitted.

getBaseTitle

Retrieve last segment in subpage, no fragment

getExtension

Retrieve media extension

Result is downcased (without leading dot).

getFile

Retrieve media page identifier

getFragment

Retrieve original (not decoded) fragment string after #

getLanguage

Retrieve language identifier

getNamespace

Retrieve namespace number

getPlain

Retrieve text with all links replaced by link titles

getProject

Retrieve project identifier within wikifarm (recommendable brief notation)

getTarget

Retrieve first target (wikilink or URL)

getTargetPage

Retrieve first target page (page name or URL of page)

Same as getTarget if no fragment.

getTitle

Retrieve first link title (wikilink or URL), or wikilink target

isBracketedLink

Does attempt match a bracketed link?

isBracketedURL

Does attempt match a bracketed URL?

isCategorization

Does attempt match a categorization?

isExternalLink

Does attempt match an external link?

isInterlanguage

Does attempt match an interlanguage link?

isInterwiki

Does attempt match an interwiki link?

isMedia

Does attempt match a media translusion?

isTitledLink

Does attempt match a titled link?

isValidLink

Does attempt match a link?

isWeblink

Does attempt match an external link?

isWikilink

Does attempt match a wikilink?

failsafe

Version ID: 2016-10-05

optional parameter 1 – required version

result: empty, if requirement not met

Examples (test page)

A test page illustrates practical use.

Functions for Lua modules (API)

All functions described above can be used by other modules:

local lucky, WLink = pcall( require, "Module:WLink" )
if type( WLink ) == "table" then
WLink = WLink.WLink()
else
-- failure; WLink is the error message
return "<span class=\"error\">" .. WLink .. "</span>"
end

Subsequently there are available:

• WLink.ansiPercent(story, space)
• WLink.formatURL()
• WLink.getArticleBase()
• WLink.getBaseTitle()
• WLink.getExtension()
• WLink.getFile()
• WLink.getFragment()

  false, if not found; but empty string if empty fragment.

  No leading # in result.

• WLink.getLanguage()
• WLink.getNamespace()
• WLink.getPlain()
• WLink.getProject()
• WLink.getTarget()
• WLink.getTargetPage()
• WLink.getTitle()
• WLink.isBracketedLink()
• WLink.isBracketedURL()
• WLink.isCategorization()
• WLink.isExternalLink()
• WLink.isInterlanguage()
• WLink.isInterwiki()
• WLink.isMedia()
• WLink.isTitledLink()
• WLink.isValidLink()
• WLink.isWeblink()
• WLink.isWikilink()
• WLink.wikilink()

  Yields table with wikilink components, else false.

  Components might be, if provided:

  • lead – leading colon : present and required, if true
  • project – project interwiki within wikifarm (recommendable brief notation)
  • lang – known language version (downcased)
  • ns – number of namespace
  • space – local canonical name of namespace
  • title – page title as provided; at least empty string

• WLink.failsafe(atleast)

  1. atleast
     optional
     nil or required version

  returns: string or false

If succeeding, the WLink.get*() return a string, the WLink.is*() true (if no exception mentioned); on failure always false.

---

local WLink = { suite  = "WLink",
serial = "2016-10-05" };
--[=[
ansiPercent()
formatURL()
getArticleBase()
getBaseTitle()
getEscapedTitle()
getExtension()
getFile()
getFragment()
getLanguage()
getNamespace()
getPlain()
getProject()
getTarget()
getTargetPage()
getTitle()
getWeblink()
isBracketedLink()
isBracketedURL()
isCategorization()
isExternalLink()
isInterlanguage()
isInterwiki()
isMedia()
isTitledLink()
isValidLink()
isWikilink()
wikilink()
failsafe()
]=]
-- local globals
local URLutil = false;
local utilURL = function ()
-- Attach URLutil library module
-- Postcondition:
--     Returns  table, with URLutil library
--     Throws error, if not available
if not URLutil then
local lucky, util = pcall( require, "Module:URLutil" );
if lucky then
if type( util ) == "table" then
URLutil = util.URLutil();
end
util = "library URLutil invalid";
end
if type( URLutil ) ~= "table" then
error( util, 0 );
end
end
return URLutil;
end -- utilURL()
local contentExtlink = function ( attempt )
-- Retrieve span of external link between brackets
-- Precondition:
--     attempt  -- string, with presumable link
--                         the first char is expected to be "["
-- Postcondition:
--     Returns  string, number, number
--                  string including whitespace
--                  number with index of relevant "["
--                  number with index after relevant "]"
--              false if nothing found
local r1 = false;
local r2 = false;
local r3 = attempt:find( "]", 2, true );
if r3 then
local s = attempt:sub( 2,  r3 - 1 );
local i = s:find( "[", 1, true );
if i then
r1 = s:sub( i + 1 );
r2 = i;
else
r1 = s;
r2 = 1;
end
else
r3 = false;
end
return r1, r2, r3;
end -- contentExtlink()
local contentWikilink = function ( attempt )
-- Retrieve span of wikilink between brackets
-- Precondition:
--     attempt  -- string, with presumable link
--                        the first two chars are expected to be "[["
-- Postcondition:
--     Returns  string, number, number
--                  string including whitespace
--                  number with index of relevant "[["
--                  number with index after relevant "]]"
--              false if nothing found
local r1 = false;
local r2 = false;
local r3 = attempt:find( "]]", 3, true );
if r3 then
local s = attempt:sub( 3,  r3 - 1 );
local i = s:find( "[[", 1, true );
if i then
r1 = s:sub( i + 2 );
r2 = i;
else
r1 = s;
r2 = 1;
end
end
return r1, r2, r3;
end -- contentWikilink()
local extractExtlink = function ( attempt )
-- Retrieve external link
-- Precondition:
--     attempt  -- string, with presumable link
--                        the first char is expected to be "["
-- Postcondition:
--     Returns  string, string
--                  first with target and title
--                  second result false if not titled
--              false if nothing found
local r1 = false;
local r2 = false;
local s = contentExtlink( attempt );
if s then
local i = s:find( "%s", 1 );
if i then
r1 = s:sub( 1,  i - 1 );
r2 = mw.text.trim( s:sub( i + 1 ) );
if r2 == "" then
r2 = false;
end
else
r1 = s;
end
if r1 then
r1 = mw.text.trim( r1 );
if r1 == ""  or
not utilURL().isResourceURL( r1 ) then
r1 = false;
end
end
if not r1 then
r2 = false;
end
end
return r1, r2;
end -- extractExtlink()
local extractWikilink = function ( attempt )
-- Retrieve wikilink
-- Precondition:
--     attempt  -- string, with presumable link
--                        the first two chars are expected to be "[["
-- Postcondition:
--     Returns  string, string
--                  first with target
--                  second result title, or false if not piped
--              false if nothing found
local r1 = false;
local r2 = false;
local s = contentWikilink( attempt );
if s then
local i = s:find( "|", 1, true );
if i then
r1 = s:sub( 1,  i - 1 );
r2 = s:sub( i + 1 );
else
r1 = s;
end
r1 = mw.text.trim( r1 );
if r1 == "" then
r1 = false;
else
r1 = r1:gsub( "_",        " " )
:gsub( " ",   " " )
:gsub( " ", " " )
:gsub( " ",   " " )
:gsub( " ",  " " )
:gsub( "  +",      " " );
r1 = mw.text.decode( r1 );
end
end
return r1, r2;
end -- extractWikilink()
local prefix = function ( ask, ahead )
-- Interprete prefix of language or project type
-- Precondition:
--     ask    -- string, with presumable prefix
--     ahead  -- true, if first segment
-- Postcondition:
--     Returns  string,string or nil
--                     first  string one of "lead", "lang", "project"
--                     second string is formatted value
--                       type is one of "lead", "lang", "project"
--              nil if nothing found
local r1, r2;
local prefixes = { b           = true,
c           = "commons",
d           = true,
commons     = true,
m           = "meta",
mediawiki   = "mw",
mw          = true,
meta        = true,
n           = true,
q           = true,
s           = true,
simple      = false,
v           = true,
voy         = true,
w           = true,
wikibooks   = "b",
wikidata    = "d",
wikinews    = "n",
wikipedia   = "w",
wikiquote   = "q",
wikisource  = "s",
wikiversity = "v",
wikivoyage  = "voy",
wikt        = true,
wiktionary  = "wikt"
};
local s = mw.text.trim( ask );
if s == "" then
if ahead then
r1 = "lead";
r2 = true;
end
else
local p;
s = s:lower();
p = prefixes[ s ];
if p == true then
r1 = "project";
r2 = s;
elseif p then
r1 = "project";
r2 = p;
elseif p == false then
r1 = "lang";
r2 = s;
elseif s:match( "^%l%l%l?$" )
and  mw.language.isSupportedLanguage( s ) then
r1 = "lang";
r2 = s;
end
end
return r1, r2;
end -- prefix()
local target = function ( attempt, lonely )
-- Retrieve first target (wikilink or URL), or entire string
-- Precondition:
--     attempt  -- string, with presumable link somewhere
--     lonely   -- remove fragment, if true
-- Postcondition:
--     Returns  string, number
--                  string, with detected link target, or entire
--                  number, with number of brackets, if found, or 2
local r1, r2 = WLink.getTarget( attempt );
if not r1 then
r1 = mw.text.trim( attempt );
r2 = 2;
end
if lonely then
local i = r1:find( "#", 1, true );
if i == 1 then
r1 = "";
elseif i then
r1 = r1:sub( 1, i - 1 );
end
end
return r1, r2;
end -- target()
function WLink.ansiPercent( attempt, alter )
-- Convert string by ANSI encoding rather than UTF-8 encoding
-- Precondition:
--     attempt  -- string, with presumable ANSI characters
--     alter    -- string or nil, to use for spaces instead of %20
-- Postcondition:
--     Returns  string, encoded
local k, s;
local r = attempt;
if alter then
r = r:gsub( " ", alter );
end
for i = mw.ustring.len( r ), 1, -1 do
k = mw.ustring.codepoint( r, i, i );
if k <= 32  or  k > 126 then
if k > 255 then
s = mw.ustring.sub( r, i, i );
if k > 2047 then
s = string.format( "%%%2X%%%2X%%%2X",
s:byte( 1, 1 ),
s:byte( 2, 2 ),
s:byte( 3, 3 ) );
else
s = string.format( "%%%2X%%%2X",
s:byte( 1, 1 ),
s:byte( 2, 2 ) );
end
else
s = string.format( "%%%2X", k );
end
r = string.format( "%s%s%s",
mw.ustring.sub( r,  1,  i - 1 ),
s,
mw.ustring.sub( r,  i + 1 ) );
end
end -- for --i
r = mw.ustring.gsub(r, '^%*', '%%2A')
return r;
end -- WLink.ansiPercent()
function WLink.formatURL( adjust )
-- Create bracketed link, if not yet
-- Precondition:
--     adjust  -- string, with URL or domain/path or bracketed link
-- Postcondition:
--     Returns  string, with bracketed link
--              false on invalid format
local r;
if type( adjust ) == "string" then
if WLink.isBracketedLink( adjust ) then
r = adjust;
else
local url = mw.text.trim( adjust );
local host;
utilURL();
host = URLutil.getHost( adjust );
if not host then
url  = "http://" .. adjust;
host = URLutil.getHost( url );
end
if host then
local path = URLutil.getRelativePath( url );
local show;
if path == "/" then
if not url:match( "/$" ) then
url = url .. "/";
end
show = host;
else
local i = path:find( "#" );
if i then
path = path:sub( 1,  i - 1 );
end
show = host .. path;
end
r = string.format( "[%s %s]", url, show );
else
r = adjust;
end
end
else
r = false;
end
return r;
end -- WLink.formatURL()
function WLink.getArticleBase( attempt )
-- Retrieve generic article title, no fragment nor brackets
-- Precondition:
--     attempt  -- string, with wikilink or page title
--                         current page title, if missing
-- Postcondition:
--     Returns  string, with identified lemma, or all
--              false on invalid format
local r;
if attempt then
local m;
r, m = target( attempt, true );
if m ~= 2 then
r = false;
end
else
r = mw.title.getCurrentTitle().text;
end
if r then
local sub = r:match( "^(.*%S) *%(.+%)$" );
if sub then
r = sub;
end
end
return r;
end -- WLink.getArticleBase()
function WLink.getBaseTitle( attempt )
-- Retrieve last segment in subpage, no fragment
-- Precondition:
--     attempt  -- string, with wikilink or page title
-- Postcondition:
--     Returns  string, with identified segment, or all
local r;
local s, m = target( attempt, true );
if m == 2 then
local sub = s:match( "/([^/]+)$" );
if sub then
r = sub;
else
r = s;
end
else
r = false;
end
return r;
end -- WLink.getBaseTitle()
function WLink.getEscapedTitle( attempt )
-- Retrieve escaped link title
-- Precondition:
--     attempt  -- string, with presumable link title
-- Postcondition:
--     Returns  string, with suitable link title
local s = mw.text.trim( attempt );
return s:gsub( "\n", " " )
:gsub( "%[", "&#91;" )
:gsub( "%]", "&#93;" )
:gsub( "|",  "&#124;" );
end -- WLink.getEscapedTitle()
function WLink.getExtension( attempt )
-- Retrieve media extension
-- Precondition:
--     attempt  -- string, with wikilink (media link) or page title
--                         if URL, PDF may be detected
-- Postcondition:
--     Returns  string, with detected downcased media type
--              false if no extension found
local r = false;
local s, m = target( attempt );
if m == 2 then
s = s:match( "%.(%a+)$" );
if s then
r = s:lower();
end
elseif s:upper():match( "[%./](PDF)%W?" ) then
r = "pdf";
end
return r;
end -- WLink.getExtension()
function WLink.getFile( attempt )
-- Retrieve media page identifier
-- Precondition:
--     attempt  -- string, with wikilink (media link) or page title
-- Postcondition:
--     Returns  string, with detected file title
--                      no namespace nor project
--              false if no file found
local r = false;
local s, m = target( attempt );
if m == 2 then
local slow    = ":" .. s:lower();
local find = function ( a )
local seek = string.format( ":%s:().+%%.%%a+$",
a:lower() );
local join = slow:find( seek );
local ret;
if join then
ret = s:sub( join + #a + 1 );
end
return ret;
end;
r = find( "file" );
if not r then
local trsl = mw.site.namespaces[6];
r = find( trsl.name );
if not r then
trsl = trsl.aliases;
for k, v in pairs( trsl ) do
r = find( v );
if r then
break; -- for k, v
end
end -- for k, v
end
end
end
return r;
end -- WLink.getFile()
function WLink.getFragment( attempt )
-- Retrieve fragment
-- Precondition:
--     attempt  -- string, with presumable fragment
-- Postcondition:
--     Returns  string, with detected fragment
--              false if no address found
local r = false;
local s, m = target( attempt );
if s then
local i = s:find( "#", 1, true );
if i then
if i > 1 then
s = s:sub( i - 1 );
i = 2;
end
if s:find( "&#", 1, true ) then
s = mw.text.decode( s );
i = s:find( "#", 1, true );
if not i then
s = "";
i = 0;
end
end
s = s:sub( i + 1 );
r = mw.text.trim( s );
if r == "" then
r = false;
elseif m == 2 then
r = r:gsub( "%.(%x%x)", "%%%1" )
:gsub( "_", " " );
r = mw.uri.decode( r, "PATH" );
end
end
end
return r;
end -- WLink.getFragment()
function WLink.getLanguage( attempt )
-- Retrieve language project identifier
-- Precondition:
--     attempt  -- string, with wikilink or page title
-- Postcondition:
--     Returns  string, with detected downcased language identifier
--              false if no project language found
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w  and  w.lang then
r = w.lang;
end
end
return r;
end -- WLink.getLanguage()
function WLink.getNamespace( attempt )
-- Retrieve namespace number
-- Precondition:
--     attempt  -- string, with wikilink or page title
-- Postcondition:
--     Returns  number, of detected namespace
--              false if no namespace found
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w  and  not w.lang  and  not w.project  and  w.ns then
r = w.ns;
end
end
return r;
end -- WLink.getNamespace()
function WLink.getPlain( attempt )
-- Retrieve text with all links replaced by link titles
-- Precondition:
--     attempt  -- string, with wikitext
-- Postcondition:
--     Returns  string, with modified wikitext without links
local r = attempt;
local i = 1;
local j, k, n, lean, s, shift, space, suffix;
while ( true ) do
j = r:find( "[", i, true );
if j then
suffix = r:sub( j );
i      = j + 1;
lean   = ( r:byte( i, i ) == 91 );
if lean then
s, k, n = contentWikilink( suffix );
else
s, k, n = contentExtlink( suffix );
end
if s then
if k > 1 then
n      = n - k;
i      = j + k;
j      = i - 1;
suffix = r:sub( j );
end
if lean then
s, shift = extractWikilink( suffix );
if s then
space = s:match( "^([^:]+):" );
if space then
space = mw.site.namespaces[ space ];
if space then
space = space.id;
end
end
if space == 6  or  space == 14 then
shift = "";
elseif not shift then
shift = s;
end
else
s     = "";
shift = "";
end
else
s, shift = extractExtlink( suffix );
if not s then
s = "";
end
if not shift then
shift = "";
end
i = i - 1;
end
if j > 1 then
s = r:sub( 1, j - 1 );
else
s = "";
end
r = string.format( "%s%s%s",
s,  shift,  r:sub( n + i ) );
i = i + #shift;
else
break; -- while true
end
else
break; -- while true
end
end -- while true
return r;
end -- WLink.getPlain()
function WLink.getProject( attempt )
-- Retrieve wikifarm project identifier
-- Precondition:
--     attempt  -- string, with wikilink or page title
-- Postcondition:
--     Returns  string, with detected downcased project identifier
--              false if no project identifier found
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w  and  w.project then
r = w.project;
end
end
return r;
end -- WLink.getProject()
function WLink.getTarget( attempt )
-- Retrieve first target (wikilink or URL)
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  string, number
--                  string, with first detected link target
--                  number, with number of brackets, if found
--              false if nothing found
local r1 = false;
local r2 = false;
local i  = attempt:find( "[", 1, true );
if i then
local m;
r1 = attempt:sub( i );
if r1:byte( 2, 2 ) == 91 then
m  = 2;
r1 = extractWikilink( r1 );
else
m  = 1;
r1 = extractExtlink( r1 );
end
if r1 then
r2 = m;
end
else
r1 = attempt:match( "%A?([hf]t?tps?://%S+)%s?" );
if r1 then
if utilURL().isResourceURL( r1 ) then
r2 = 0;
else
r1 = false;
end
else
r1 = false;
end
end
return r1, r2;
end -- WLink.getTarget()
function WLink.getTargetPage( attempt )
-- Retrieve first target page (page name or URL of page)
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  string, with first detected linked page
--              false if nothing found
local r1, r2 = WLink.getTarget( attempt );
if r1 then
local i = r1:find( "#", 1, true );
if i then
if i == 1 then
r1 = false;
else
r1 = mw.text.trim( r1:sub( 1,  i - 1 ) );
end
end
end
return r1, r2;
end -- WLink.getTargetPage()
function WLink.getTitle( attempt )
-- Retrieve first link title (wikilink or URL), or wikilink target
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  string, with first detected link target
--              false if nothing found
local r = false;
local i = attempt:find( "[", 1, true );
if i then
local s1, s2;
r = attempt:sub( i );
if r:byte( 2, 2 ) == 91 then
s1, s2 = extractWikilink( r );
if s2 then
r = s2;
else
r = s1;
end
else
s1, r = extractExtlink( r );
end
end
return r;
end -- WLink.getTitle()
function WLink.getWeblink( attempt, anURLutil )
-- Retrieve bracketed link from resource URL
-- Precondition:
--     attempt    -- string, with URL, or something different
--     anURLutil  -- library module object, or nil
-- Postcondition:
--     Returns  string, with first detected link target
--              false if nothing found
local second = ".ac.co.go.gv.or.";
local r;
if type( anURLutil ) == "table" then
URLutil = anURLutil;
else
utilURL();
end
if URLutil.isResourceURL( attempt ) then
local site = URLutil.getAuthority( attempt );
local show;
if #attempt == #site then
site = site .. "/";
end
show = URLutil.getTop3domain( "//" .. site );
if show then
local scan   = "[%./](%a+)(%.%l%l%.)(%a+)$";
local search = "." .. show;
local s1, s2, s3 = search:match( scan );
if s2 then
if not second:find( s2, 1, true ) then
show = string.format( "%s.%s", s2, s3 );
end
else
show = false;
end
end
if not show then
show = URLutil.getTop2domain( "//" .. site );
if not show then
show = URLutil.getHost( "//" .. site );
end
end
r = string.format( "[%s %s]", attempt, show );
else
r = attempt;
end
return r;
end -- WLink.getWeblink()
function WLink.isBracketedLink( attempt )
-- Does attempt match a bracketed link?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local r = false;
local i = attempt:find( "[", 1, true );
if i then
local s = attempt:sub( i );
if s:byte( 2, 2 ) == 91 then
s = extractWikilink( s );
else
s = extractExtlink( s );
end
if s then
r = true;
end
end
return r;
end -- WLink.isBracketedLink()
function WLink.isBracketedURL( attempt )
-- Does attempt match a bracketed URL?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local s, r = WLink.getTarget( attempt );
return ( r == 1 );
end -- WLink.isBracketedURL()
function WLink.isCategorization( attempt )
-- Does attempt match a categorization?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w  and  w.ns == 14
and  not ( w.lead or w.lang or w.project )
and  w.title ~= "" then
r = true;
end
end
return r;
end -- WLink.isCategorization()
function WLink.isExternalLink( attempt )
-- Does attempt match an external link?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local s, r = WLink.getTarget( attempt );
if r then
r = ( r < 2 );
end
return r;
end -- WLink.isExternalLink()
function WLink.isInterlanguage( attempt )
-- Does attempt match an interlanguage link?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w and w.lang and not w.project and not w.lead
and  w.title ~= "" then
r = true;
end
end
return r;
end -- WLink.isInterlanguage()
function WLink.isInterwiki( attempt )
-- Does attempt match an interwiki link within wikifarm?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w  and  ( w.lang or w.project )  and  w.title ~= "" then
r = true;
end
end
return r;
end -- WLink.isInterwiki()
function WLink.isMedia( attempt )
-- Does attempt match a media translusion?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local r = false;
local s, m = WLink.getTarget( attempt );
if m == 2 then
local w = WLink.wikilink( s );
if w  and  w.ns == 6
and  not ( w.lead or w.lang or w.project )
and  w.title ~= ""
and  WLink.getExtension( w.title ) then
r = true;
end
end
return r;
end -- WLink.isMedia()
function WLink.isTitledLink( attempt )
-- Does attempt match a titled link?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local r = false;
local i = attempt:find( "[", 1, true );
if i then
local c, n;
local s = attempt:sub( i );
if s:byte( 2, 2 ) == 91 then
n = s:find( "%]%]", 5 );
c = "|";
else
n = s:find( "%]", 8 );
c = "%s%S";
end
if n then
local m = s:find( c, 2 );
if m  and  m + 1 < n  and  WLink.getTarget( attempt ) then
r = true;
end
end
end
return r;
end -- WLink.isTitledLink()
function WLink.isValidLink( attempt )
-- Does attempt match a link?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local s, r = WLink.getTarget( attempt );
if r then
r = true;
end
return r;
end -- WLink.isValidLink()
function WLink.isWikilink( attempt )
-- Does attempt match a wikilink?
-- Precondition:
--     attempt  -- string, with presumable link somewhere
-- Postcondition:
--     Returns  boolean
local s, m = WLink.getTarget( attempt );
return ( m == 2 );
end -- WLink.isWikilink()
function WLink.wikilink( attempt )
-- Retrieve wikilink components
-- Precondition:
--     attempt  -- string, with presumable link
--                         expected to be enclosed in "[[" "]]"
--                         else wikilink
-- Postcondition:
--     Returns  table or false
--              table of assignments with { type, value}
--                       type is one of "lead",
--                          "project", "lang",
--                          "ns", "space", "title"
--              false if nothing found
local s = contentWikilink( attempt );
local got, n, r;
if not s then
s = attempt;
end
i = s:find( "|", 1, true );
if i then
s = s:sub( 1, i - 1 );
end
got = mw.text.split( s, ":" );
n   = table.maxn( got );
if n == 1 then
r = { title = mw.text.trim( s ) };
else
local j, k, o, v;
r = { title = "" };
if n > 4 then
k = 4;
else
k = n - 1;
end
j = k;
for i = 1, j do
s = mw.text.trim( got[ i ] );
if s ~= "" then
o = mw.site.namespaces[ mw.text.trim( got[ i ] ) ];
if o then
r.ns    = o.id;
r.space = o.name;
k = i + 1;
j = i - 1;
break; -- for i
end
end
end -- for i
for i = 1, j do
o, v = prefix( got[ i ],  ( i == 1 ) );
if o then
if r[ o ] then
k = i;
break; -- for i
else
r[ o ] = v;
end
else
k = i;
break; -- for i
end
end -- for i
for i = k, n do
r.title = r.title .. got[ i ];
if i < n then
r.title = r.title .. ":";
end
end -- for i
end
if r.lead and
( r.project  or  not r.title  or
( not r.lang  and  r.ns ~= 6  and  r.ns ~= 14 ) ) then
r.lead = false;
end
return r;
end -- WLink.wikilink()
function WLink.failsafe( assert )
-- Retrieve versioning and check for compliance
-- Precondition:
--     assert  -- string, with required version, or false
-- Postcondition:
--     Returns  string with appropriate version, or false
local r;
if assert  and  assert > WLink.serial then
r = false;
else
r = WLink.serial;
end
return r
end -- WLink.failsafe()
local function Template( frame, action, leave, lone )
-- Run actual code from template transclusion
-- Precondition:
--     frame   -- object
--     action  -- string, with function name
--     leave   -- true: keep whitespace around
--     lone    -- true: permit call without parameters
-- Postcondition:
--     Return string; might be error message
local lucky = true;
local s = false;
local r = false;
local space;
for k, v in pairs( frame.args ) do
if k == 1 then
if leave then
s = v;
else
s = mw.text.trim( v );
end
elseif action == "ansiPercent"  and  k == "space" then
if v ~= "" then
space = v;
end
elseif k ~= "template" then
lucky = false;
if r then
r = r .. "|";
else
r = "Unknown parameter: ";
end
r = string.format( "%s%s=", r, k );
end
end -- for k, v
if lucky then
if s or lone then
lucky, r = pcall( WLink[ action ],  s,  space );
else
r = "Parameter missing";
lucky = false;
end
end
if lucky then
if type( r ) == "boolean" then
if r then
r = "1";
else
r = "";
end
end
else
r = string.format( "<span class=\"error\">%s</span>", r );
end
return r;
end -- Template()
-- Export
local p = { };
p.ansiPercent = function ( frame )
return Template( frame, "ansiPercent" );
end
p.formatURL = function ( frame )
return Template( frame, "formatURL" );
end
p.getArticleBase = function ( frame )
return Template( frame, "getArticleBase", false, true );
end
p.getBaseTitle = function ( frame )
return Template( frame, "getBaseTitle" );
end
p.getEscapedTitle = function ( frame )
return Template( frame, "getEscapedTitle" );
end
p.getExtension = function ( frame )
return Template( frame, "getExtension" );
end
p.getFile = function ( frame )
return Template( frame, "getFile" );
end
p.getFragment = function ( frame )
return Template( frame, "getFragment" );
end
p.getInterwiki = function ( frame )
return Template( frame, "getInterwiki" );
end
p.getLanguage = function ( frame )
return Template( frame, "getLanguage" );
end
p.getNamespace = function ( frame )
return tostring( Template( frame, "getNamespace" ) );
end
p.getPlain = function ( frame )
return Template( frame, "getPlain" );
end
p.getProject = function ( frame )
return Template( frame, "getProject" );
end
p.getTarget = function ( frame )
return Template( frame, "getTarget" );
end
p.getTargetPage = function ( frame )
return Template( frame, "getTargetPage" );
end
p.getTitle = function ( frame )
return Template( frame, "getTitle" );
end
p.getWeblink = function ( frame )
return Template( frame, "getWeblink" );
end
p.isBracketedLink = function ( frame )
return Template( frame, "isBracketedLink" );
end
p.isBracketedURL = function ( frame )
return Template( frame, "isBracketedURL" );
end
p.isCategorization = function ( frame )
return Template( frame, "isCategorization" );
end
p.isExternalLink = function ( frame )
return Template( frame, "isExternalLink" );
end
p.isInterlanguage = function ( frame )
return Template( frame, "isInterlanguage" );
end
p.isInterwiki = function ( frame )
return Template( frame, "isInterwiki" );
end
p.isMedia = function ( frame )
return Template( frame, "isMedia" );
end
p.isTitledLink = function ( frame )
return Template( frame, "isTitledLink" );
end
p.isValidLink = function ( frame )
return Template( frame, "isValidLink" );
end
p.isWeblink = function ( frame )
return Template( frame, "isWeblink" );
end
p.isWikilink = function ( frame )
return Template( frame, "isWikilink" );
end
p.failsafe = function ( frame )
local since = frame.args[ 1 ];
if since then
since = mw.text.trim( since );
if since == "" then
since = false;
end
end
return WLink.failsafe( since ) or "";
end
p.WLink = function ()
return WLink;
end
return p;