Why can't I access my instance variables?

ruby-talk
1

I’m having trouble accessing instance variables directly. What’s wrong
with this…

class Level1
def initialize
@var1='var1 set.'
end

def printvar1
@var1
end
end

l1=Level1.new
print l1.printvar1, "\n"
print l1.var1

I get the following output:

% ruby test.rb
var1 set.
test.rb:13: undefined method `var1’ for #<Level1:0x23d5e8 @var1=“var1
set.”> (NoMethodError)

I’m running version 1.8.0 preview3 on OS X.

Donglai

2

I’m having trouble accessing instance variables directly. What’s wrong
with this…
[snip]
var1 set.
test.rb:13: undefined method `var1’ for #<Level1:0x23d5e8 @var1=“var1
set.”> (NoMethodError)

Try this (untestted)… does it work ?

class Level1
def initialize
@var1=‘var1 set.’
end
attr_reader :var1

def printvar1
@var1
end
end

l1=Level1.new
print l1.printvar1, “\n”
print l1.var1

···

On Tue, 01 Jul 2003 06:36:15 +0900, Donglai Gong wrote:

–
Simon Strandgaard

3

Donglai Gong wrote:

I’m having trouble accessing instance variables directly. What’s wrong
with this…

class Level1
def initialize
@var1=‘var1 set.’
end

def printvar1
@var1
end
end

l1=Level1.new
print l1.printvar1, “\n”
print l1.var1

I get the following output:

% ruby test.rb
var1 set.
test.rb:13: undefined method `var1’ for #<Level1:0x23d5e8 @var1=“var1
set.”> (NoMethodError)

I’m running version 1.8.0 preview3 on OS X.

Donglai

variables are private by default. You can write get and set methods to
read and write their values.

class Level1
def initialize
@var1=‘var1 set.’
end

def printvar1
@var1
end

def var1
@var1 # just return @val1
end

def var1= (newval)
# test the validity of newval here
@val1 = newval
end

end

if you feel lazy and have no need to have any tests in your accessor
methods (get and set methods) then there is:

class Foo
attr_reader :readable_var
attr_writer :writable_var
attr_accessor :readable_and_writable_var
end

I hope this helps :slight_smile:

···

–
dc -e
4ddod3dddn1-89danrn10-dan3+ann6dan2an13dn1+dn2-dn3+5ddan2/9+an13nap