[erlang-questions] Blog: Erlang Fractal Benchmark

Mats Cronqvist <>
Tue Jun 5 16:01:42 CEST 2007

Ulf Wiger wrote:
> It seems counter-intuitive at first, doesn't it? (:
> Adding checking to the code shouldn't speed things up,
> but the thing is that, being dynamically typed, Erlang will
> have to do type checking in all the multiplications, etc,
> checking first the operands, and then the result.
> But if the compiler can deduce (because of the guards)
> what the type signature is, it can generate much more
> efficient code, foregoing redundant type checks.
> I think(*) it's pretty much generally true that adding type
> guards never slows things down, but adds compile-time
> info that can be used by Dialyzer as well as in some
> optimizations.

   so having better syntax for type guards would be a big win...


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