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From: sdl@linus.UUCP (Steven D. Litvintchouk)
Newsgroups: comp.lang.smalltalk
Subject: subclasses of Float in Smalltalk/V
Message-ID: <56225@linus.UUCP>
Date: 16 Jun 89 20:31:37 GMT
Organization: The MITRE Corp., Bedford, MA
Lines: 40


I currently own a copy of Smalltalk/V for the Mac.

I am trying to create some subclasses of Float.  For example, subclass
Degree, which would be constrained to have values in the range 0.0 ..
360.0.  (For example, adding an instance of Degree to another instance
of Degree would return the sum mod 360.0.)

The problem is:  How can you create instances of class Degree?  I
tried:

	Degree fromInteger: 50

But fromInteger is apparently a primitive which returns a Float.

I also tried  
	Degree new

But Smalltalk/V considers the expression  (Float new) to be an error.

I guess the problem is how to implement a conversion method for class
Float called "asDegree," which will return an instance of class Degree
equal to the Float number mod 360.0.  I see no way to accomplish this
in Smalltalk/V.


Any ideas?


Steven Litvintchouk
MITRE Corporation
Burlington Road
Bedford, MA  01730

Fone:  (617)271-7753
ARPA:  sdl@mitre-bedford.arpa
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