From: "Iñaki Baz Castillo" <ibc@...>
Date: 2009-12-06T11:20:01+09:00
Subject: Re: Why doesn't Ruby "compile" strings?

El Domingo, 6 de Diciembre de 2009, Kirk Haines escribió:
> On Sat, Dec 5, 2009 at 6:48 PM, Iñaki Baz Castillo <ibc@aliax.net> wrote:
> > Hi, the following code:
> >
> > -------------------
> > #!/usr/bin/ruby
> >
> > require "benchmark"
> >
> > HELLO_WORLD = "hello world"
> >
> > 1.upto(4) do
> >
> >        print "Benchmark using HELLO_WORLD:   "
> >        puts Benchmark.realtime { 1.upto(500000) {|i| HELLO_WORLD.upcase }
> > }
> >
> >        print "Benchmark using \"hello_world\": "
> >        puts Benchmark.realtime { 1.upto(500000) {|i| "hello_world".upcase
> > } }
> >
> >        print "Benchmark using 'hello_world': "
> >        puts Benchmark.realtime { 1.upto(500000) {|i| 'hello_world'.upcase
> > } }
> >
> > end
> > -------------------
> >
> >
> > This clearly shows that using a constant string is faster than using a
> > string
> > writen into the script. So I wonder: why doesn't Ruby "precompile"
> > internally
> > the strings appearing in the script?
> 
> This is because when you are using the constant, you are referring to the
> same object every time.
> 
> When you are using the string literals, the interpreter doesn't know what
> you are going to do with that string literal, so it's not really safe for
>  it to assume that it can use a single ruby object to represent all
>  instances of it.

Why not? It's obviously a string writen in the script, with no variables into 
it and so...




-- 
Iñaki Baz Castillo <ibc@aliax.net>