From: Ara.T.Howard [mailto:Ara.T.Howard@noaa.gov]
Sent: Thursday, 15 September 2005 1:22 PM
To: ruby-talk ML
Subject: Re: params v.s. @params in rails?
def method_missing(m, *a, &b)
idx = FIELDS.index m.to_s
return self[idx] if idx
super
end
this routes through method_missing each time, which is expensive
Intuitively it sounds expensive, because [I imagine] ruby needs to
traverse then inheritance tree for the object, but in a simply case like
your example is it still expensive, ie, is method_missing much more
expensive than any other call ?
Neville
no. it is just a method. it's pretty easy to tell what happens from eval.c:
...
/* is it in the method cache? */
ent = cache + EXPR1(klass, mid);
if (ent->mid == mid && ent->klass == klass) {
if (!ent->method)
return method_missing(recv, mid, argc, argv, scope==2?CSTAT_VCALL:0);
klass = ent->origin;
id = ent->mid0;
noex = ent->noex;
body = ent->method;
}
...
it probably isn't an issue in this simple example but if you were, say,
scanning a ten thousand things to determine an index then you be a winner. it
definitely would require being able to do some sort of caching to make defining
the method worth bothering. i was just trying to show how you could have
something like 'price' work without it actually being 'defined' anywhere.
rails leverages ruby to the hilt with things like this.
cheers.
-a
···
On Thu, 15 Sep 2005, Neville Burnell wrote:
From: Ara.T.Howard [mailto:Ara.T.Howard@noaa.gov]
Sent: Thursday, 15 September 2005 1:22 PM
To: ruby-talk ML
Subject: Re: params v.s. @params in rails?
def method_missing(m, *a, &b)
idx = FIELDS.index m.to_s
return self[idx] if idx
super
end
this routes through method_missing each time, which is expensive
Intuitively it sounds expensive, because [I imagine] ruby needs to traverse
then inheritance tree for the object, but in a simply case like your example
is it still expensive, ie, is method_missing much more expensive than any
other call ?
--
email :: ara [dot] t [dot] howard [at] noaa [dot] gov
phone :: 303.497.6469
Your life dwells amoung the causes of death
Like a lamp standing in a strong breeze. --Nagarjuna
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