Already stalled in Pick Axe book - could use some help

[Jeff Rohrer]

Hi, total noob here. I'm only on page 25 of the Pick Axe book and I'm a
little stuck:

I'm running Ruby version 1.8.4 on Windows XP Home Edition. I'm entering
code via irb.

Here's the problem: I enter the following code from the book:

class Song
def initialize(name, artist, duration)
@name = name
@artist = artist
@duration = duration
end

def to_s
"Song: #@name--#@artist (#@duration)"
end
end

I successfully load the code using a file called song.rb here:

irb(main):008:0> load "c:/code/song.rb"
=> true

Now the book states that if I type in this:
song = Song.new("Bicylops", "Fleck", 260)
song.to_s

I should see this:

"Song: BicylopsFleck(260)"

But I'm not, I'm getting this:

irb(main):013:0> song = Song.new("Bicylops", "Fleck", 260)
=> #<Song:0x2c80440 @duration=260, @name="Bicylops", @artist="Fleck">
irb(main):014:0> song.to_s
=> "#<Song:0x2c80440>"

Obviously I'm still seeing the object ID when I should be seeing the
string. Any help will be appreciated.

Regards,
Jeff

 

[James Britt]

Hi, total noob here. I'm only on page 25 of the Pick Axe book and I'm a
little stuck:

I'm running Ruby version 1.8.4 on Windows XP Home Edition. I'm entering
code via irb.

Here's the problem: I enter the following code from the book:

class Song
def initialize(name, artist, duration)
@name = name
@artist = artist
@duration = duration
end

def to_s
"Song: #@name--#@artist (#@duration)"
end
end

I just tried this on WinXP, ruby 1.8.4 (2005-12-24) [i386-mswin32]

demo.rb has the code you provided.

d:\tmp>irb
irb(main):001:0> load 'demo.rb'
=> true
irb(main):002:0> song = Song.new("Bicylops", "Fleck", 260)
=> #<Song:0x2b1a370 @name="Bicylops", @duration=260, @artist="Fleck">
irb(main):003:0> song.to_s
=> "Song: Bicylops--Fleck (260)"
irb(main):004:0>

I think you may have something different in your actual source code.



--
James Britt

"Simplicity of the language is not what matters, but
simplicity of use."
- Richard A. O'Keefe in squeak-dev mailing list

 

[Eero Saynatkari]

Hi, total noob here. I'm only on page 25 of the Pick Axe book and I'm a
little stuck:

I'm running Ruby version 1.8.4 on Windows XP Home Edition. I'm entering
code via irb.

Here's the problem: I enter the following code from the book:

<elided />

irb(main):008:0> load "c:/code/song.rb"
=> true

Your code seems to be fine--however, you mention using
irb but also, obviously, #load a file here. If the file
contains the old code and you #load it after you have
entered the new class code in irb, it will redefine your
methods.

Try and just enter the above class definition either in
irb or the file (and #load it in irb), but not both and
see if that helps.

 

[Jeff Rohrer]

Try and just enter the above class definition either in

irb or the file (and #load it in irb), but not both and
see if that helps.

Got it. Thanks! That works, now I can move on:

C:\>irb
irb(main):001:0> class Song
irb(main):002:1> def initialize(name, artist, duration)
irb(main):003:2> @name = name
irb(main):004:2> @artist = artist
irb(main):005:2> @duration = duration
irb(main):006:2> end
irb(main):007:1> def to_s
irb(main):008:2> "Song: #@name--#@artist (#@duration)"
irb(main):009:2> end
irb(main):011:0> song = Song.new("Bicyclops", "Fleck", 260)
=> #<Song:0x2c8bc78 @duration=260, @name="Bicyclops", @artist="Fleck">
irb(main):012:0> song.to_s
=> "Song: Bicyclops--Fleck (260)"

 

[ChrisH]

Hi, total noob here. I'm only on page 25 of the Pick Axe book and I'm a
little stuck: ....snip
def to_s
"Song: #@name--#@artist (#@duration)"

....
You forgot the curly braces, should be
"Song: #{@name}--#{@artist} (#{@duration})"


Cheers

 

[Derek Chesterfield]

...
You forgot the curly braces, should be
"Song: #{@name}--#{@artist} (#{@duration})"

Actually, #@ is a shortcut, when it is an instance variable.

 

[Phrogz]

...
You forgot the curly braces, should be
"Song: #{@name}--#{@artist} (#{@duration})"

The curly braces are not needed for class, instance, or global
variables. (And maybe some other situations I don't know about.) Jeff's
original code is just fine.