Markup spec/BNF/Links
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EBNF grammar project
This page references elements defined in Markup spec/BNF/Fundamental elements and Markup spec/BNF/Article title
- Internal and external links work fundamentally differently in MediaWiki, and should likely be treated separately. --Brion VIBBER 04:08, 29 May 2006 (UTC) reply
- Do you mean to separate out their definitions, or to remove the <link> element and add its current definition wherever it would otherwise be used? I think it makes logical sense to keep the top-level <link> definition, but I have separated out the definitions, which I hope will aid clarity. --HappyDog 13:46, 29 May 2006 (UTC) reply
Link definitions
[edit ]Top level definition
[edit ]<link> ::= <internal-link> | <external-link>
Internal links
[edit ]<internal-link> ::= <internal-link-start> <article-link> [ "#" <section-id> ] [ <pipe> [<link-description>] ] <internal-link-end> [<extra-description>] /* Parser actually considers namespace and subpages to just be part of the article-title, and deals with them later. */ <article-link> ::= [<interwiki-prefix> | ":" ] [<namespace-prefix>] <article-title> /* if subpages: */ /* not properly fleshed out, haven not tried all the combinations */ <article-link> ::= [<interwiki-prefix> | ":"] [<namespace-prefix>] <article-title> | "/" <article-title> | { "../" } [<article-title>] <article-title> ::= { [<title-legal-chars> | "%" ] } + /* Specified using regex format, obviously... */ <title-legal-chars> ::= " %!\"$&'()*,\\-.\\/0-9:;=?@A-Z\\\\^_`a-z~\\x80-\\xFF+" <interwiki-prefix> ::= <interwiki> ":" <interwiki> ::= STRING_FROM_DB <namespace-prefix> ::= [<namespace>] ":" <namespace> ::= STRING_FROM_CONFIG /* is it? parser.php gives it as "[_0-9A-Za-z\x80-\xff]" */ <link-description> ::= LEGAL_ARTICLE_ENTITY <extra-description> ::= <letter> [<extra-description>] <internal-link-start> ::= "[[" <internal-link-end> ::= "]]" <pipe> ::= "|" /* Almost anything seems to be allowed, but it won't necessarily be treated as an actual section title */ <section-id> ::= { [<title-legal-chars> | "%" | "#" ] } +
- Remarks
- Logically, internal-link should be matched in preference to external-link, as that's how the current parser does it. However, the current parser also explicitly checks for an accidental match of an external link in an inside link (that is, [[http://foo.com]]) and converts it back to an external link.
if (preg_match('/^\b(?:' . wfUrlProtocols() . ')/', $m[1])) { $s .= $prefix . '[[' . $line ; continue; }
Categories
[edit ]In the current parser, categories are just a mildly special case of an internal link. But to the user they seem quite different, and the final behaviour is very different. So let's treat them specially.
/* section-ids are technically tolerated currently. but they do nothing and aren't used. */ /* similarly a pipe without a sort key is technically tolerated but isn't useful. */ <category> ::= <internal-link-start> <category-namespace> ":" <article-title> [ <pipe> <sort-key> ] <internal-link-end> <category-namespace> ::= NS_CATEGORY /* set in languages/messages/MessagesXx.php. By default, "Category" */ /* <article-title> specified above. for a category, it's possibly more restrictive. */ /* other bits specified above. */
- Remarks
- A link *to* a category is handled by internal-link above.
Rendering
[edit ]A category link produces no inline text. However, the fact of the link (with possible manual sort key) is stored, and possibly rendered by the skin.
External links
[edit ]<external-link> ::= <external-link-start> <url> [<whitespace>] [<link-description>] <external-link-end> | <url> <url> ::= <protocol> <url-path> <protocol> ::= ALLOWED_PROTOCOL_FROM_CONFIG (e.g. "http://", "mailto:") <url-path> ::= <url-char> [<url-path>] <url-char> ::= LEGAL_URL_ENTITY <external-link-start> ::= "[" <external-link-end> ::= "]"
Transformations
[edit ]Internal link to HTML
[edit ]URL = <a href=1ドル?title=2ドル3ドル"4ドル title="2ドル">5ドル6ドル</a>
Where
if <interwiki> is blank 1ドル = internal variable $wgScript else 1ドル = looked up in DB, based on value of <interwiki> 2ドル = <namespace-prefix> <article-link> If destination page exists 3ドル = "&action=edit" 4ドル = " class="new"" else 3ドル and 4ドル are blank If <description> is blank 5ドル = <article-link> else 5ドル = <description> 6ドル = <extra-description>