kendear wrote:
> i wonder in Ruby, is there a line method to do something like in C
>
>
> print_val("Array[3] + 1")
>
> and get the printout of
>
>
> Array[3] + 1 is 3.345
>

Here you go:
def print_val(str)
puts "#{str} is #{eval(str)}"
end


This should do what you want. Be wary of side effects, though. For
example, to display the value of "a += 3" requires evaluation, and that
changes the value of "a" (and when you remove this debugging line, your
program no longer works the way you expect).

Have fun,
Dan

On Sep 15, 2007, at 7:11 AM, Dan Zwell wrote:

> Here you go:
> def print_val(str)
> puts "#{str} is #{eval(str)}"
> end

That didn't work for me. I had modify it like so:

foo = [1, 2, 3, 4, 5]
def print_val(str)
puts "#{str} is #{eval(str, TOPLEVEL_BINDING)}"
end
print_val("foo[3] + 1")

Regards, Morton

Morton Goldberg wrote:
> On Sep 15, 2007, at 7:11 AM, Dan Zwell wrote:
>
>> Here you go:
>> def print_val(str)
>> puts "#{str} is #{eval(str)}"
>> end
>
> That didn't work for me. I had modify it like so:
>
> foo = [1, 2, 3, 4, 5]
> def print_val(str)
> puts "#{str} is #{eval(str, TOPLEVEL_BINDING)}"
> end
> print_val("foo[3] + 1")
>
> Regards, Morton
>
>

You're right, thanks. When I tested this, I used the first poster's
variable name, "Array". So it worked for me, but only because I happened
to use a name with global slope.

Dan

On Sep 15, 5:22 am, Morton Goldberg <m_goldb...@ameritech.net> wrote:
> That didn't work for me. I had modify it like so:
>
> foo = [1, 2, 3, 4, 5]
> def print_val(str)
> puts "#{str} is #{eval(str, TOPLEVEL_BINDING)}"
> end
> print_val("foo[3] + 1")


it works but then if print_val is called inside an instance method,
then it won't work.