EBNF notation for HTML5 tag syntax

html5TagSyntax.bnf

tag-open := '<' tag-name ws* attr-list? ws* '>'
tag-empty := '<' tag-name ws* attr-list? ws* '/>'
tag-close := '</' tag-name ws* '>'


attr-list := (ws+ attr)*
attr := attr-empty | attr-unquoted | attr-single-quoted | attr-double-quoted

attr-empty := attr-name
attr-unquoted := attr-name ws* = ws* attr-unquoted-value
attr-single-quoted := attr-name ws* = ws* ' attr-single-quoted-value '
attr-double-quoted := attr-name ws* = ws* " attr-double-quoted-value "

tag-name := (alphabets | digits)+                      # Can digits become first letter?
attr-name := /[^\s"'>/=\p{Control}]+/

# These three items should not contain 'ambiguous ampersand'...
attr-unquoted-value := /[^\s"'=<>`]+/
attr-single-quoted-value := /[^']*/
attr-double-quoted-value := /[^"]*/

alphabets := [a-zA-Z]
digits := /[0-9]/
ws := /\s/

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