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From: jellinghaus-robert@CS.Yale.EDU (Rob Jellinghaus)
Newsgroups: comp.lang.eiffel
Subject: What is this error?
Message-ID: <53250@yale-celray.yale.UUCP>
Date: 9 Mar 89 23:19:04 GMT
Sender: root@yale.UUCP
Reply-To: jellinghaus-robert@CS.Yale.EDU (Rob Jellinghaus)
Organization: Yale University Computer Science Dept, New Haven CT  06520-2158
Lines: 40

I don't expect to get a reply to this in time to be of any help to me,
but I'll ask anyway.  I'm working on my hash table class (recall that
I have a deferred class HASHABLE defining features hash:integer and
same:boolean, which must be inherited from to use the class).  I've
got it written, and it compiles almost all the way through, except then
it says

Eiffel configuration manager
	 (version 2.1)
Pass 4 on class hash_table
"hash_table", 78: p4/type4.c: Datum_macro (): unknown basic type for an attribute: B0
Please send information regarding this error
to Interactive Software Engineering.
-------------------------------------------------

*** es: error in pass4

What kind of information should I send?  What could I be doing wrong?
The error occurs in a very simple routine:

	index(x: T) is
			-- x's index in array
		do
			Result := x.hash mod size
				-- random hash function
		ensure
			0 <= Result; Result < size
		end;

which simply asks the datum to hash itself, and then converts that number
to be within the bounds of the hash table.  And, you guessed it, the line
beginning "Result :=" is line 78.

And this is only the first class I've ever tried to build with Eiffel.
Needless to say, I am very disappointed.

Rob Jellinghaus                | "Next time you see a lie being spread or a
jellinghaus-robert@CS.Yale.EDU |  bad decision being made out of sheer ignor-
ROBERTJ@{yalecs,yalevm}.BITNET |  ance, pause, and think of hypertext."
{everyone}!decvax!yale!robertj |     -- K. Eric Drexler, _Engines of Creation_