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Re: Smart variables, dumb variables
From: |
rm |
Subject: |
Re: Smart variables, dumb variables |
Date: |
Thu, 15 Aug 2002 19:27:09 +0200 |
User-agent: |
Mutt/1.3.24i |
On Thu, Aug 15, 2002 at 06:34:28PM +0200, Marius Vollmer wrote:
> address@hidden writes:
>
> > oops, i forgot to mention goops. I was thinking of GOOPS generic
> > metods:
> > |
> > | (define-generic +)
> > | (define-method (+ (a <string>) (b <string>))
> > | (string-append a b))
> > |
> > | (+ 41 1)
> > | => 42
> > |
> > | (+ "Foo" "bar")
> > | => "Foobar"
> > |
>
> In this example you are creating a new variable with the name "+" and
> store a new generic in it. That variable would not carry the
> declarations that the variable named "+" in the guile-core module
> carries. So the compiler would treat your variable "+" like any other
> and wont perform wrong optimizations on it.
Symbolic code, so to say -- i wasn't shure about whether '+' was all-
ready a "generic". Couldn't test my code due to guile segfaulting (see
my bugreport :)
BTW, i'm not really happy with guiles current behavior regarding declaring
a generic that's allready existing. I'd expect that a (define-generic foo)
on a function that's allready will be a no-opt. The call (and syntax)
of define-generic "feels" like a compiler makro and not like something
that creates a new binding for its only parameter. I just tried my own
code and was astonished to see that after my declaration the primitive
'+' wasn't reachable anymore :-/ Now, i could (perhaps, i'm an inpatient
person) live with that iff there was an easy way to test whether something
is allready declared generic, but:
(use-modules (oop goops))
+
=> #<primitive-procedure +>
(define-method (+ (a <string>) (b <string>)) (string-append a b))
+
=> #<primitive-generic +>
Humpf! I know, this is actually a nice optimisation in this code, but
it shouldn't be so visible.
[...]
>
> > In the presence of a generic method system (i.e. function dispatch
> > on the type signature of the arguments) this seems to be rather
> > non-trivial, or do you want to propose to make guile a [statically]
> > typed language ?
>
> No, no, no. :-) As you can see above, types are still checked at
> run-time, but without having to call out-of-line functions all the
> time.
So, if i understand you right, the compiler would generate code
that contains _two_ branches, one for the fast numeric code
(inlined) and one for the normal generic method dispatch?
> > > So my next proposal is to add declarations to variables... :-)
> >
> > And a type system ;-)
>
> No, that would be fun, sure, but not in this life...
As long as guile1.6 get's out in time ;-)
Ralf
> --
> GPG: D5D4E405 - 2F9B BCCC 8527 692A 04E3 331E FAF8 226A D5D4 E405
- Re: Smart variables, dumb variables, (continued)
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/14
- Re: Smart variables, dumb variables, tomas, 2002/08/14
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/14
- Re: Smart variables, dumb variables, rm, 2002/08/14
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/14
- Re: Smart variables, dumb variables, rm, 2002/08/15
- Re: Smart variables, dumb variables, Lynn Winebarger, 2002/08/15
- Re: Smart variables, dumb variables, rm, 2002/08/15
- Re: Smart variables, dumb variables, Rob Browning, 2002/08/15
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/15
- Re: Smart variables, dumb variables,
rm <=
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/15
- Re: Smart variables, dumb variables, rm, 2002/08/15
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/15
- Re: Smart variables, dumb variables, rm, 2002/08/15
- Re: Smart variables, dumb variables, Neil Jerram, 2002/08/19
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/19
- Re: Smart variables, dumb variables, rm, 2002/08/20
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/26
- Re: Smart variables, dumb variables, tomas, 2002/08/15
- Re: Smart variables, dumb variables, Marius Vollmer, 2002/08/15