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From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.forth
Subject: Re: How could have I factored this better?
Date: Fri, 20 May 2016 15:44:20 -0700
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Darin Murphy <murphy.darin@gmail.com> writes:
> Hi everybody. I created the following program and would like to know
> how I could have factored and documented it better.

Here's my version, which possibly uses some gforth words:

    : checkneg ( n -- ) 0 < abort" need a non-negative integer" ;
    : star  ( -- ) '*' emit ;
    : stars ( n -- ) dup checkneg 0 ?do star loop ;
    : solid-box-stars { cols rows } cr
        cols checkneg
        rows checkneg
        rows 0 ?do
            cols stars cr
        loop ;


Differences from yours:

1. The stack comment in your STAR word is ( n -- ) but should be ( -- )
2. I used ABORT to break out of the error check since the number
   is invalid and there's no way to continue.  In a bigger program
   you might want to catch the error with CATCH.
3. I checked for < 0 instead of < 1, since it seems perfectly ok to
   me to print zero stars without it being an error.  That meant 
   changing the loops to ?DO.  The repeat/while stuff was clumsy.
4. I used gforth locals for the args to solid-box-stars.  Maybe
   that's controversial but it avoids some stack juggling, assuming
   you want the interface to stay what you wrote.