FIB in PowerPC assembly and in JONESFORTH

Recently I've been teaching myself PowerPC assembly through porting JONESFORTH to PowerPC on Mac OS X. It struck me to run the same little fibonacci-sequence microbenchmark that I ran lo these many years past. The results were interesting:

Gordon Weakliem writes about literal hash-table syntax, and touches on some of the problems that programmers run in to with floating-point numbers. He writes:

12 years ago, I spent half a day in the debugger trying to figure out why the computer would not believe that 0.0 == 0.0 [...]

This triggered two thoughts:

floating-point numbers in GUIs should be represent...

Submatches vs. Recursion in ThiNG Patterns

Submatching in a pattern, +var@pattern, looks suspiciously similar to recursion in a value, var=value. In each case, we expect a value which is both named and processed, and in each case, a binding is introduced into code. The processing in the submatch case is a further pattern-match operation, and in the recursion case it is a nested evaluation.

The main difference, besides the overall context, between the two forms is the scope of the introduced binding: in...
Partial-evaluation of Monads in Scheme - A New Hope?

The other day, I noted that my generic-monad-in-Scheme implementation suffered from the flaw of not being able to type-check monad assemblies before any actions had been executed, and that in general such ahead-of-time checking is not possible without abstract interpretation of some kind, because the functional code in the right-hand-side of the bind operator can decide

Monads in Scheme - A Retraction

I don't know what crack I was smoking the other day, but my implementation of general monads not only does not have the property I claimed for it, viz. that it provides the same level of type-checking as Haskell ahead of execution-time, but it cannot provide s...

Monads in Scheme - Update

Just quickly revisiting the article the other day on monads in Scheme: I've just updated my experimental implementation to propagate monad type information both forward from the arguments to the result of the bind operation and backward from the expected result type to the required argument typ...
Trait Composition in ThiNG

Trait composition is one of the fundamental ideas in ThiNG r3/r4. It's used to assemble pattern-matching clauses in functions, to assemble definitions into a module, to (functionally-) update data-structure, to augment generic functions with new definitions, and to assemble modules into programs.
```
define cons [+car: [+cdr: [First: car Rest: cdr]]]
define map [+f: loop=[(cons +a +d): (cons (f a) (loop d)) Nil:Nil]]
```
Both these definitions use objects with more ...
Recent spikes in ThiNG

Since I last posted about ThiNG, my ideas have shifted closer to those expressed in Jay & Kesner's Pure Pattern Calculus, and I've built a few experimental spikes to gain some concrete experience with some of the language features and designs I've been thinking about - among other things, that traits and modules share a number of core characteristics, and that using monads to structure effects can be profitabl...
Source Code Repositories

We make a few programs that we've developed available on this server. You can download them from our source-code repositories:
Darcs
Most of our projects are currently maintained in these archives.

You can browse the darcs-controlled code with Daan Leijen's Extensible records with scoped labels: describes an intriguing system for typing records similar to those I'm trying to define with ThiNG.

Barry Jay ...

eighty-twenty news

FIB in PowerPC assembly and in JONESFORTH

Submatches vs. Recursion in ThiNG Patterns

Partial-evaluation of Monads in Scheme - A New Hope?

Monads in Scheme - A Retraction

Monads in Scheme - Update

Trait Composition in ThiNG

Recent spikes in ThiNG

Source Code Repositories