Copies the instance variables of +object+ into +self+.
Instance variable names in the +exclude+ array are ignored. If +object+
responds to +protected_instance_variables+ the ones returned are
also ignored. For example, Rails controllers implement that method.
In both arrays strings and symbols are understood, and they have to include
the at sign.
<ruby>
class C
def initialize(x, y, z)
@x, @y, @z = x, y, z
end
def protected_instance_variables
%w(@z)
end
end
a = C.new(0, 1, 2)
b = C.new(3, 4, 5)
a.copy_instance_variables_from(b, [:@y])
# a is now: @x = 3, @y = 1, @z = 2
</ruby>
In the example +object+ and +self+ are of the same type, but they don't need to.
NOTE: Defined in +active_support/core_ext/object/instance_variables.rb+.
h4. Silencing Warnings, Streams, and Exceptions
The methods +silence_warnings+ and +enable_warnings+ change the value of +$VERBOSE+ accordingly for the duration of their block, and reset it afterwards:
WARNING: Using a pair of ++...++ for fixed-width font only works with *words*; that is: anything matching <tt>\A\w+\z</tt>. For anything else use +<tt>...</tt>+, notably symbols, setters, inline snippets, etc:
