Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!mnetor!seismo!columbia!caip!nike!ucbcad!ucbvax!sdcsvax!sdcc6!sdcc3!ma168a
From: ma168a@sdcc3.ucsd.EDU (John Wavrik)
Newsgroups: net.lang.forth
Subject: smudge, etc.
Message-ID: <3488@sdcc3.ucsd.EDU>
Date: Thu, 24-Jul-86 13:15:13 EDT
Article-I.D.: sdcc3.3488
Posted: Thu Jul 24 13:15:13 1986
Date-Received: Fri, 25-Jul-86 08:00:19 EDT
Organization: U.C. San Diego, Academic Computer Center
Lines: 21
Keywords: information hiding


WARNING:
The use of a SMUDGE bit is not the only method used to prevent a dictionary
search from locating the word being defined. In some implementations the
word is not put in the search path (CONTEXT) until definition is finished.
  
  To summarize the discussion on "information hiding", here are the
techniques that have been mentioned:
  
   (1) to realize that you don't need it (you can re-use a variable
       name, for example, effectively rendering its earlier use local)
   (2) to use vocabularies
   (3) to deface the name field
   (4) to set the smudge bit (special case of #3) -- when applicable
   (5) to relink the dictionary
   (6) to use a technique of "temporary variables" (see Forth Dimensions
       vol III #6) to produce headerless words.

						   John J Wavrik
						   Math Dept - UCSD
		sdcc3!ma168a@SDCSVAX.UCSD.EDU