On 6/23/2010 9:59 PM, Rob Stewart wrote:
When considered as the inverse of quote(), unquote() should simply strip leading and trailing delimiters and look for escaped delimiters and escaped escape characters within. To supply the extra semantics you've suggested, quote() must also be enhanced significantly.
I've attached a new version of unquote() (along with quote() and the updated test program) with that behavior. As implemented, unquote() stops at the first delimiter it finds after the first character (whether the first is a delimiter or not). Until then, it "unescapes" escaped characters. Note the last test case: a = "embedded "; b = quote(a); b += "quotation mark\""; BOOST_ASSERT("\"embedded \"quotation mark\"" == b); b = unquote(b); BOOST_ASSERT(a == b); In that test, "quotation mark\"" is ignored by unquote() because it stops writing to the output iterator up finding the quotation mark after the space following "embedded." It is possible for unquote() to leave the embedded quotation mark, as if it had been escaped, but it would complicate the algorithm -- unless I assume random access iterators -- and its description. This version doesn't care whether the first or last characters are delimiters, thus "muddling through" as Eric suggested. I haven't taken the time to consider other reasonable ideas for delimiter support such as multiple character delimiters or distinct start and end delimiters. ___ Rob