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67 lines
2.5 KiB
Plaintext
67 lines
2.5 KiB
Plaintext
Production rules for lexical tokens
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===================================
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This file provides a complete set of production rules for the tokens generated
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by the lexer. In case of ambiguity, the longest match wins.
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Components
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----------
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ident ::= '-'? nmstart nmchar*
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name ::= nmchar+
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nmstart ::= [a-zA-Z] | '_' | nonascii | escape
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nonascii ::= [#x80-#xD7FF#xE000-#xFFFD#x10000-#x10FFFF]
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unicode ::= '\' [0-9a-fA-F]{1,6} wc?
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escape ::= unicode | '\' [^\n\r\f0-9a-fA-F]
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nmchar ::= [a-zA-Z0-9] | '-' | '_' | nonascii | escape
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num ::= [-+]? ([0-9]+ | [0-9]* '.' [0-9]+)
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string ::= '"' (stringchar | "'")* '"' | "'" (stringchar | '"')* "'"
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stringchar ::= urlchar | #x20 | #x29 | '\' nl
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urlchar ::= [#x9#x21#x23-#x26#x28#x2A-#x7E] | nonascii | escape
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nl ::= #xA | #xD #xA | #xD | #xC
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w ::= wc*
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wc ::= #x9 | #xA | #xC | #xD | #x20
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Tokens
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------
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IDENT ::= ident
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ATKEYWORD ::= '@' ident
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STRING ::= string
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INVALID_STRING ::= '"' (stringchar | "'")* [^"] | "'" (stringchar | '"')* [^']
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HASH ::= '#' name
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NUMBER ::= num
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PERCENTAGE ::= num '%'
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DIMENSION ::= num ident
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URI ::= "url(" w (string | urlchar*) w ')'
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UNICODE-RANGE ::= [Uu] '+' [0-9a-fA-F?]{1,6} ('-' [0-9a-fA-F]{1,6})?
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CDO ::= "<!--"
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CDC ::= "-->"
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S ::= wc+
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COMMENT ::= "/*" [^*]* '*'+ ([^/] [^*]* '*'+) '/'
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FUNCTION ::= ident '('
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INCLUDES ::= "~="
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DASHMATCH ::= "|="
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PREFIXMATCH ::= "^="
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SUFFIXMATCH ::= "$="
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SUBSTRINGMATCH ::= "*="
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CHAR ::= any other character, except " or '
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Differences from the CSS3 Syntax module specification
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-----------------------------------------------------
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1) UNICODE-RANGE is case insensitive (it's uppercase only in the spec)
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2) escape follows CSS2.1. CSS3 defines it as:
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escape ::= unicode | '\' [#x20-#x7E#x80-#xD7FF#xE000-#xFFFD#x10000-#x10FFFF]
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3) urlchar omits ' and ):
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a) If ' is permitted verbatim then, as stringchar inherits from urlchar,
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single quoted strings may contain verbatim single quotes. This is
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clearly nonsense.
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b) If ) is permitted verbatim then it becomes impossible to determine the
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true end of URI. Thus, for sanity's sake, it's omitted here.
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4) stringchar explicitly includes ). See 3(b) for why it won't inherit it
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from urlchar as the spec implies.
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5) BOM ::= #xFEFF is omitted. It is assumed that any leading BOM will be
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stripped from the document before lexing occurs.
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