tag self

Ruby Extensions vs. Smalltalk Primitives

Posted by Rick DeNatale Mon, 04 Jun 2007 14:16:00 GMT

One of the ways in which Ruby differs from Smalltalk is in how much of the implementation is buried in C, which forms a barrier for deep understanding.

For the purposes of this article, I’m going to use the term extension a little loosely to refer to both core library and extension code written in C.

For example, in Ruby, much of the code which implements core classes like Array, is implemented by C code. This is good for performance, but for those with a need or desire to grok the code, not so much. In contrast, Smalltalk has a large brigade of Collection classes which are written in Smalltalk.

This is not to say that Smalltalk doesn’t use the equivalent of extensions. Smalltalk calls them primitives.

There are some interesting differences which might be interesting for the Ruby Core team to ponder, if they haven’t already.

Boolean Implementations, Ruby, Smalltalk and self

Posted by Rick DeNatale Tue, 10 Oct 2006 16:43:00 GMT

The topic of defining a new ruby class which could have instances that, like false and nil were seen as a boolean which was not true, just came up on ruby-talk.

This has come up before, and it turns out that in Ruby being untrue is reserved to these two specific instances.

The boolean test is pretty deeply engrained into the implementation of ruby. The actual test seems to be defined in the RTEST macro in ruby.h

#define Qnil   ((VALUE)4)
#define RTEST(v) (((VALUE)(v) & ~Qnil) != 0)

Which means that any object whose reference VALUE has any bit set other than the 3rd LSB is true.

In ruby, the control flow statements like ‘if’ aren’t messages, but are ‘compiled’ into a direct test and conditional branch.

Even Smalltalk, which defined even if/then/else as a message, e.g.

    booleanValue ifTrue:[Transcript show:'true'] ifFalse: [Transcript show:'false']

Tended to cheat in the implementation… Read more...

Posted in ruby, smalltalk | Tags implementation, performance, self | 2 comments | no trackbacks

Performance Anxiety

Posted by Rick DeNatale Tue, 26 Sep 2006 19:17:00 GMT

I've been meaning to write about Ruby performance for a while, and a recent blog post by an old friend and colleague, got me off my proverbial.

The old friend is John Duimovich, who wrote about the relative performance of C++ and Smalltalk and what that could mean for ruby.

John's message is important for those who bemoan the performance of Ruby, and I plan to expand on that message in this and later posts to this blog, but first a few words about Mr. Duimovich.