-
if someone attempts to modify a constant, why does ruby choose to
emit a warning instead of a fatal error? -
is there a beast called a ‘global constant’? i tried defining $Foo
and ruby allows me to rebind $Foo later.
thanks,
···
–
dave
Hi,
- if someone attempts to modify a constant, why does ruby choose to
emit a warning instead of a fatal error?
If it is a fatal error, something like Ruby embedded editor will meet
serious problems, e.g.
M-x eval-ruby-expression
Eval: Foo = 42
bang!
- is there a beast called a ‘global constant’? i tried defining $Foo
and ruby allows me to rebind $Foo later.
No. $Foo is a plain global variable.
matz.
···
In message “warning modifying constant & ‘global constant’” on 02/08/26, David Garamond davegaramond@icqmail.com writes:
Yukihiro Matsumoto wrote:
- is there a beast called a ‘global constant’? i tried defining $Foo
and ruby allows me to rebind $Foo later.No. $Foo is a plain global variable.
thanks matz.
i want to protect some global variables without having to resort to
setting $SAFE to 4. can we use some proxying mechanism, or override an
object method to trap assignment/binding? freeze() only protect the
object value, and does not prevent rebinding.
···
–
dave
What problems would there be with making it an exception?
I would hope that the embedded editor would already handle exceptions
properly.
Paul
···
On Mon, Aug 26, 2002 at 06:49:55PM +0900, Yukihiro Matsumoto wrote:
- if someone attempts to modify a constant, why does ruby choose to
emit a warning instead of a fatal error?If it is a fatal error, something like Ruby embedded editor will meet
serious problems, e.g.M-x eval-ruby-expression
Eval: Foo = 42
bang!
i want to protect some global variables without having to resort to
setting $SAFE to 4. can we use some proxying mechanism, or override an
object method to trap assignment/binding? freeze() only protect the
object value, and does not prevent rebinding.
ruby has internally read only variables, for example :
pigeon% ruby -e '$LOAD_PATH = "aaa"'
-e:1: can't set variable $LOAD_PATH (NameError)
pigeon%
but
pigeon% ruby -e '$LOAD_PATH << "aaa"'
pigeon%
well,
pigeon% ruby -e '$LOAD_PATH.freeze; $LOAD_PATH << "aaa"'
-e:1:in `<<': can't modify frozen array (TypeError)
from -e:1
pigeon%
but
pigeon% ruby -e '$LOAD_PATH.freeze; $LOAD_PATH[0] << "aaa"'
pigeon%
etc
Guy Decoux
Kernel.trace_var?
chandler@greyhound:~$ irb
irb(main):001:0> trace_var :$global, proc{|v| $global = ‘foo’}
nil
irb(main):002:0> $global = ‘pet’
“pet”
irb(main):003:0> p $global
“foo”
nil
Perhaps make Globals class and make all the variables as instance or class
variables with only attr_reader set or only getter methods?
-michael
···
On Monday 26 August 2002 05:11, David Garamond wrote:
Yukihiro Matsumoto wrote:
- is there a beast called a ‘global constant’? i tried defining $Foo
and ruby allows me to rebind $Foo later.No. $Foo is a plain global variable.
thanks matz.
i want to protect some global variables without having to resort to
setting $SAFE to 4. can we use some proxying mechanism, or override an
object method to trap assignment/binding? freeze() only protect the
object value, and does not prevent rebinding.
++++++++++++++++++++++++++++++++++++++++++
Michael C. Libby x@ichimunki.com
public key: http://www.ichimunki.com/public_key.txt
web site: http://www.ichimunki.com
++++++++++++++++++++++++++++++++++++++++++
“David Garamond” wrote in
…
thanks matz.
i want to protect some global variables without having to resort to
setting $SAFE to 4. can we use some proxying mechanism, or override an
object method to trap assignment/binding? freeze() only protect the
object value, and does not prevent rebinding.
Actually freezing a class as a similar effect on its
class, local variables and constants
Hi,
···
In message “Re: warning modifying constant & ‘global constant’” on 02/08/27, Paul Brannan pbrannan@atdesk.com writes:
M-x eval-ruby-expression
Eval: Foo = 42
bang!What problems would there be with making it an exception?
for example, eval-current-buffer may cause trouble if it redefines
contants.
matz.