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17/09/2007, 08h49

Hi --

On Mon, 17 Sep 2007, Summercool Summercool wrote:

> the following program for showing Variable / Method Ambiguity
>
> def a
> print "Function 'a' called\n"
> 99
> end
>
> for i in 1..2
> if i == 2
> print "a=", a, "\n"
> else
> a = 1
> print "a=", a, "\n"
> end
> end
>
> will produce the result:
>
> a=1
> Function 'a' called
> a=99
>
> (as described in the PickAx2 book, p. 329)
>
> So at first I thought a Ruby program is interpreted? If interpreted,
> then the interpreter will see the "a = 1" at first as treat "a" as a
> variable, and then the second time it sees "a", the interpreter should
> treat it as a variable again, not as a method.

No, because there's no such variable in scope. The second time through
the loop, there's no assignment to a, and the first variable a has
gone out of scope. So the only thing that "a" could mean, outside of
an assignment, is the method a.

David

> So does that mean a
> Ruby program is not interpreted but compiled into some bytecode first?
> But then, sometimes I run a Ruby program and then it can run all the way
> until it see an "undefined local variable"... so that means it probably
> is not compiled... or else it would have stopped without running
> anything at all.
>
> So is a Ruby program interpreted or compiled?
> --
> Posted via http://www.ruby-forum.com/.
>

--
* Books:
RAILS ROUTING (new! http://www.awprofessional.com/title/0321509242)
RUBY FOR RAILS (http://www.manning.com/black)
* Ruby/Rails training
& consulting: Ruby Power and Light, LLC (http://www.rubypal.com)

17/09/2007, 08h49	#3
David A. Black Messages: n/a Hébergeur:	Re: Variable / Method Ambiguity Hi -- On Mon, 17 Sep 2007, Summercool Summercool wrote: > the following program for showing Variable / Method Ambiguity > > def a > print "Function 'a' called\n" > 99 > end > > for i in 1..2 > if i == 2 > print "a=", a, "\n" > else > a = 1 > print "a=", a, "\n" > end > end > > will produce the result: > > a=1 > Function 'a' called > a=99 > > (as described in the PickAx2 book, p. 329) > > So at first I thought a Ruby program is interpreted? If interpreted, > then the interpreter will see the "a = 1" at first as treat "a" as a > variable, and then the second time it sees "a", the interpreter should > treat it as a variable again, not as a method. No, because there's no such variable in scope. The second time through the loop, there's no assignment to a, and the first variable a has gone out of scope. So the only thing that "a" could mean, outside of an assignment, is the method a. David > So does that mean a > Ruby program is not interpreted but compiled into some bytecode first? > But then, sometimes I run a Ruby program and then it can run all the way > until it see an "undefined local variable"... so that means it probably > is not compiled... or else it would have stopped without running > anything at all. > > So is a Ruby program interpreted or compiled? > -- > Posted via http://www.ruby-forum.com/. > -- * Books: RAILS ROUTING (new! http://www.awprofessional.com/title/0321509242) RUBY FOR RAILS (http://www.manning.com/black) * Ruby/Rails training & consulting: Ruby Power and Light, LLC (http://www.rubypal.com)