How should I call eval from member function that binds to global context?
Something like
$binding = binding
class InterpreterCallback
def methods(expr)
begin
return eval(expr, $binding).class.instance_methods(false).sort
rescue ScriptError, StandardError
printf "ERR: %s\n", $! || 'exception raised'
return
end
end
end
but this does not work when I am calling InterpreterCallback::methods from C++ (for example when new local variable in the global context is created).
Also I do not understand following
This code:
puts eval("var" ).class
puts eval("var").class.instance_methods(false).sort
var = "";
produces:
NilClass
&
^
inspect
nil?
to_a
to_f
to_i
to_s
and this code
puts eval("var" ).class
puts eval("var").class.instance_methods(false).sort
produces
undefined local variable or method `var' for main:Object (NameError)
which is exactly what I would expect in the first case also.
Thank you
There is the TOPLEVEL_BINDING, although I don't if it will help you.
J.
···
On 7/30/06, Karel Michek <KMichek@seznam.cz> wrote:
How should I call eval from member function that binds to global context?
This code:
puts eval("var" ).class
puts eval("var").class.instance_methods(false).sort
var = "";
produces:
NilClass
[...]
and this code
puts eval("var" ).class
puts eval("var").class.instance_methods(false).sort
produces
undefined local variable or method `var' for main:Object (NameError)
which is exactly what I would expect in the first case also.
When the "var" String is eval()ed, var="" has already been parsed. Ruby
already knows that var refers to a local variable, so "var" will be
interpreted correspondingly. When this happens, var hasn't been assigned to,
though, so the returned value is nil.
This is what's happening:
eval("a") # => nil
a = 1 # since the parser has seen this, "a" will be a local
# in code parsed from now on. Its value is nil until it is
# initialized.
Compare it to the following situation, where the block is parsed before you
assign to a:
instance_eval { a } # =>
a = nil
# ~> -:1: undefined local variable or method `a' for main:Object (NameError)
# ~> from -:1
···
On Sun, Jul 30, 2006 at 07:44:06PM +0900, Karel Michek wrote:
--
Mauricio Fernandez - http://eigenclass.org - singular Ruby