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From: ForthNet@willett.pgh.pa.us (ForthNet articles from GEnie)
Newsgroups: comp.lang.forth
Subject: What's WRONG with Forth?
Message-ID: <2417.UUL1.3#5129@willett.pgh.pa.us>
Date: 27 Feb 91 03:08:40 GMT
Organization: (n.) to be organized.  But that's not important right now.
Lines: 32

Category 2,  Topic 9
Message 48        Tue Feb 26, 1991
ATFURMAN [Alan F.]           at 01:49 PST
 
For fast relief from stack balance headaches, try this:

After writing a definition with before-and-after stack comments (you DO use
before-and-after stack comments, don't you?...of course you do) read through
the definition while thinking of, or mumbling, the stack depth as you read
each word within the definition.  The final stack depth should agree with the
"after" stack comment.

 Example:

  : foo ( n1 n2 -- n3)
        * 3 + x @ / dup . ;

 Here is how the read-through would go (start with depth of 2):

          *      3      +      x      @      /     dup     .
 "two"  "one"  "two"  "one"  "two"  "two"  "one"  "two"  "one"

Starting with a two-deep stack, we end with a one-deep stack, and conclude
that the word's behavior conforms to the stack comment.

When there are conditional branches or loops, this becomes trickier to do--but
even more worth the trouble, too.
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