3 ms·

The whitespace rule as stated there is as far as my understanding goes incorrect. Whitespace is allowed between quoted strings and word tokens, not between ind

The whitespace rule as stated there is as far as my understanding goes incorrect. Whitespace is allowed between quoted strings and word tokens, not between individual production rules (if that is the term). By that I mean "q = 0 . 1" is invalid, "q = 0.1" however is valid. That simplifies things a lot. If you lex the headers in two phases (handle line continuations and header combination first, feed joined lines to parser) HTTP is reasonably simple to parse.

d0mine 14y ago
yes. "Implied LWS" rule says it can be included between any tokens, but tokens MUST be separated by a delimiter therefore if 0.000 is allowed (no delimiters) then it means it is a single token and "implied LWS" rule is not applicable for the 0.000 part in the quality values: * implied LWS The grammar described by this specification is word-based. Except where noted otherwise, linear white space (LWS) can be included between any two adjacent words (token or quoted-string), and between adjacent words and separators, without changing the interpretation of a field. At least one delimiter (LWS and/or separators) MUST exist between any two tokens (for the definition of "token" below), since they would otherwise be interpreted as a single token.* </quote> http://www.ietf.org/rfc/rfc2616.txt http://www.ietf.org/rfc/rfc2616.txt Quality values: qvalue = ( "0" [ "." 0*3DIGIT ] ) | ( "1" [ "." 0*3("0") ] ) It seems the author is mistaken in allowing: 0 . 0 0 0