Edi Weitz edi@agharta.de writes:
Which browser sends requests that look like "foo.html?foo="?
Consider I want to redirect client to auth.html with auth-res boolean parameter turned on. What should I pass as the URI? If I use "?auth-res=NIL" or "?auth-res=0", both of them returns T, because neither "NIL", nor "0" is NIL. Hence, I prefer to use "?auth-res=" But in this case, I cannot know if the boolean parameter is supplied and it's value is NIL, or the parameter isn't even supplied. (Because, in both situations it returns NIL.)
I can cope with this problem, by making an extra (assoc 'auth-res (get-parameters)) probe everytime I need that verbosity. But wouldn't it be better just to specify a ":exist-p auth-res-exist-p" option in the lambda list of D-E-H.
Regards.