148 lines
4 KiB
EBNF
148 lines
4 KiB
EBNF
(* Markdown EBNF Grammar *)
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document = { block } ;
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block = heading
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| horizontal_rule
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| code_block
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| quote_block
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| list
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| table
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| paragraph
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| blank_line ;
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(* Headings *)
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heading = atx_heading | setext_heading ;
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atx_heading = "#" { "#" } [ " " ] inline_text newline ;
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setext_heading = inline_text newline
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( ( "=" { "=" } ) | ( "-" { "-" } ) ) newline ;
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(* Horizontal Rule *)
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horizontal_rule = ( ( "*" [ " " ] "*" [ " " ] "*" { [ " " ] "*" } )
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| ( "-" [ " " ] "-" [ " " ] "-" { [ " " ] "-" } )
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| ( "_" [ " " ] "_" [ " " ] "_" { [ " " ] "_" } ) ) newline ;
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(* Code Blocks *)
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code_block = fenced_code_block | indented_code_block ;
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fenced_code_block = "```" [ language_identifier ] newline
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{ code_line }
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"```" newline ;
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indented_code_block = { " " code_line } ;
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code_line = { character - newline } newline ;
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language_identifier = { letter | digit | "-" | "+" } ;
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(* Quote Blocks *)
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quote_block = { ">" [ " " ] ( inline_text | "" ) newline } ;
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(* Lists *)
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list = unordered_list | ordered_list ;
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unordered_list = { unordered_list_item } ;
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ordered_list = { ordered_list_item } ;
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unordered_list_item = [ " " { " " } ] ( "*" | "+" | "-" ) " " inline_text newline
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{ continuation_line } ;
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ordered_list_item = [ " " { " " } ] digit { digit } "." " " inline_text newline
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{ continuation_line } ;
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continuation_line = " " inline_text newline ;
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(* Tables *)
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table = table_header table_separator { table_row } ;
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table_header = "|" { table_cell "|" } newline ;
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table_separator = "|" { table_align_spec "|" } newline ;
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table_row = "|" { table_cell "|" } newline ;
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table_cell = { character - ( "|" | newline ) } ;
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table_align_spec = [ ":" ] "-" { "-" } [ ":" ] ;
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(* Paragraphs *)
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paragraph = inline_text { newline inline_text } newline ;
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(* Inline Elements *)
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inline_text = { inline_element } ;
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inline_element = emphasis
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| strong
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| code_span
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| link
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| image
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| autolink
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| line_break
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| plain_text ;
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emphasis = ( "*" non_asterisk_text "*" )
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| ( "_" non_underscore_text "_" ) ;
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strong = ( "**" non_asterisk_text "**" )
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| ( "__" non_underscore_text "__" ) ;
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code_span = "`" { "`" } non_backtick_text { "`" } "`" ;
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link = "[" link_text "]" "(" link_url [ " " link_title ] ")" ;
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image = "!" "[" alt_text "]" "(" image_url [ " " image_title ] ")" ;
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autolink = "<" ( url | email ) ">" ;
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line_break = " " newline | "\\" newline ;
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(* Text Content *)
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plain_text = { character - special_char } ;
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non_asterisk_text = { character - "*" } ;
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non_underscore_text = { character - "_" } ;
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non_backtick_text = { character - "`" } ;
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link_text = { character - ( "[" | "]" ) } ;
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alt_text = { character - ( "[" | "]" ) } ;
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link_url = { character - ( "(" | ")" | " " ) } ;
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image_url = { character - ( "(" | ")" | " " ) } ;
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link_title = quote_string ;
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image_title = quote_string ;
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quote_string = ( '"' { character - '"' } '"' )
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| ( "'" { character - "'" } "'" ) ;
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url = "http" [ "s" ] "://" { character - ">" } ;
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email = { character - ( "@" | ">" ) } "@" { character - ">" } ;
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(* Utilities *)
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blank_line = newline ;
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special_char = "*" | "_" | "`" | "[" | "]" | "(" | ")" | "#" | ">" | "|" | "!" | "\\" ;
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newline = "\n" | "\r\n" ;
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character = letter | digit | symbol | " " ;
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letter = "a" | "b" | "c" | "d" | "e" | "f" | "g" | "h" | "i" | "j" | "k" | "l" | "m"
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| "n" | "o" | "p" | "q" | "r" | "s" | "t" | "u" | "v" | "w" | "x" | "y" | "z"
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| "A" | "B" | "C" | "D" | "E" | "F" | "G" | "H" | "I" | "J" | "K" | "L" | "M"
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| "N" | "O" | "P" | "Q" | "R" | "S" | "T" | "U" | "V" | "W" | "X" | "Y" | "Z" ;
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digit = "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" ;
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symbol = "!" | "@" | "#" | "$" | "%" | "^" | "&" | "*" | "(" | ")" | "-" | "_" | "="
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| "+" | "[" | "]" | "{" | "}" | "\\" | "|" | ";" | ":" | "'" | '"' | "," | "."
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| "<" | ">" | "/" | "?" | "~" | "`" ;
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