[Newbies] Polymorphic or: with block argument
Jecel Assumpcao Jr.
jecel at merlintec.com
Mon Sep 18 17:08:34 UTC 2017
Sean P. DeNigris wrote on Sun, 17 Sep 2017 06:44:35 -0700 (MST)
> Ralph Johnson wrote
> > Yes, when the compiler sees exp or: [ ... ] then it assumes that "exp"
> > is
> > a boolean-valued expression and generates code that fails if it isn't.
> I remember the pain of tripping over these little "everything is a message
> send to an object*" sins as a new Smalltalker. I wonder now, with the
> incredible speed of Cog, Spur, Sista, etc., if these devil's bargains from
> prior decades are still necessary. It would be psychologically satisfying
> (and nice for newbies) to remove the asterisk from the principle above.
That was one of the changes between Self 1.0 and 2.0. The first version
had a list of selectors it did special tricks for and it was annoying
for programmers to have two code fragments that looked very similar to
each other perform very differently. When Craig Chambers did the second
generation compiler he noticed that he could handle all cases uniformly.
The same should apply to Cog and Sista. Eliminating such tricks would
hurt the interpreter, however.
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