Markup spec/BNF/Article
EBNF grammar project
Wiki-page
[edit]The top-level element (start symbol) is wiki-page
which describes the contents of a page. A page can either be a redirect or a normal article.
<wiki-page> ::= <redirect> [<article>] | [<article>]
<redirect> ::= <redirect-tag> <characters> <internal-link-start> <article-link> (<internal-link-end> | <pipe> | EOL)
<redirect-tag> ::= FROM_LANGUAGE_FILE
<internal-link-start>, <article-link>, <internal-link-end> and <pipe> are defined in Links Notes:
The <redirect-tag> is language-specific, and may have more than one possible value. By default the value for the right-hand-side of the expression (replacing FROM_LANGUAGE_FILE) is "#redirect"
, but in Estonian it is "#redirect" | "#suuna"
. This match is case-insensitive (though this again may be overridden in the language file).
<characters> should be non-greedy, matching the largest subset of characters that does not contain <internal-link-start>.
For example, <redirect>
will match the following, and treat it as a redirect to foo:
#REDireCTnon%^sense[[foo|and this is parsed as article content
- Interwiki prefixes may not be supported in redirect links. (Is this configurable?)
- The <article> following the redirect link is not rendered. However, it is parsed. So, interwiki links, category links and even normal links are still treated and behave "normally".
- Anchors (Article#Section) are supported, but not yet described in the grammar.
Article
[edit]This describes the contents of an article. An article consists of blocks, which come in two flavours: paragraphs and special blocks. Both of them end with a newline. Paragraphs are separated by empty lines.
<article> ::= <special-block-and-more> | <paragraph-and-more>
<special-block-and-more> ::= <special-block> ( EOF | [<newline>] <special-block-and-more>
| (<newline> | "") <paragraph-and-more> )
<paragraph-and-more> ::= <paragraph> ( EOF | [<newline>] <special-block-and-more>
| <newline> <paragraph-and-more> )
The nonterminals special-block-and-more
and paragraph-and-more
are not disjoint; the parser should first try to match against special-block-and-more
.
The expression (<newline> | "")
is a greedy version of [<newline>]
. If both the empty string and a newline can be matched, then the former expression matches the newline, while the latter expression would match the empty string according to the conventions on Markup spec/BNF.
- For the definition of special block, see Markup spec/BNF/Special block.
- Note
- Any line that does not start with one of the following is not a special block:
" " | "{|" | "#" | ";" | ":" | "*" | "="
- This should assist in parsing.
- Hey, that's almost what it says in the current parser. I must be onto something. Wonder why it doesn't cover space or = though.
if (!$piece['lineStart'] && preg_match('/^(?:{\\||:|;|#|\*)/', $text)) /*}*/{
Paragraph
[edit]Every paragraph ends with a newline character. A paragraph translated in a <p> element.
<paragraph> ::= <newline> [<lines-of-text>] | <lines-of-text>
<lines-of-text> ::= <line-of-text> [<lines-of-text>]
<line-of-text> ::= <inline-text> <newline>
- For the definition of inline text, see Markup spec/BNF/Inline text.
The recursion in the second rule should be non-greedy, i.e., it should match as few lines as possible. For instance,
abc
----
should be parsed as one line-of-text
and one horizontal-rule
, but
abc
---
should be parsed as two line-of-text
nonterminals.
If a paragraph starts with a newline, the newline is as a <br> element.
Block HTML
[edit](not referred to yet) BlockHTML = Pre | Blockquote | TableHTML | Div | HeaderHTML ;
String Types
[edit]This text came from Meta-Wiki. It's not immediately compatible with the surrounding text (it's EBNF, rather than BNF, for a start). However it is much more precise about the nature of lines and captures rules about whitespace normalisation.
Fundamental strings
WikiMarkupCharacters = "|" | "[" | "]" | "*" | "#" | ":" | ";" | "<" | ">" | "=" | "'" | "{" | "}" ;
UnicodeCharacter = ? all supported Unicode characters ? - Whitespaces ;
UnicodeWiki = UnicodeCharacter - WikiMarkupCharacters ;
PlainText = UnicodeWiki
| "<nowiki><nowiki></nowiki>" { "|" | "[" | "]" | "<" | ">" | "{" | "}" } "<nowiki></nowiki></nowiki>"
| UnicodeWiki { " " } ( "*" | "#" | ":" | ";" )
| UnicodeWiki [ " " ] "=" [ " " ] UnicodeWiki
| UnicodeWiki "'"
| " '" UnicodeWiki ;
WhiteSpaces = " " | NewLine | ? carriage return ? | ? line feed ? | ? tab ? | ? variants of spaces ? ;
NewLine = ? carriage return and line feed ? ;
Article strings
Line = PlainText { PlainText } { " " { " " } PlainText { PlainText } } ;
Text = Line { Line } { NewLine { NewLine } Line { Line } } ;
Titles
PageName = TitleCharacter , { [ " " ] TitleCharacter } ;
PageNameLink = TitleCharacter , { [ " " | "_" ] TitleCharacter } ;
SectionTitle = ( SectionLinkCharacter - "=" ) { [ " " ] ( SectionLinkCharacter - "=" ) } ;
SectionLink = SectionLinkCharacter { [ "_" ] SectionLinkCharacter } ;
LinkTitle = { UnicodeCharacter { " " } } ( UnicodeCharacter - "]" ) ;
TitleCharacter = UnicodeCharacter - BadTitleCharacters ;
BadTitleCharacters = "[" | "]" | "{" | "}" | "<" | ">" | "_" | "|" | "#" ;
SectionLinkCharacter = UnicodeCharacter - BadSectionLinkCharacters ;
BadSectionLinkCharacters = "[" | "]" | "|" ;