Thanks Robert and Yuri,
As a ruby newbie I'm finding that I'm getting a little stuck. I've been programming in Java/C like languages for about 15 years, so maybe I'm just having trouble getting used to the brave new world, so perhaps you'll bear with me while I take you through some details.
I really like ruby but I'm finding it hard to get to the bottom of things when I do get errors.
My current situation involves a module called Gruff. I've mailed my problems to the gruff forums on rubyforge, and we're working on it there, however I'd really like to be able to help solve the problem myself.
I've downloaded gruff and rmagick using gems, and I'm trying a gruff code sample in irb (I previously tried an rmagick sample and that works):
require 'rubygems'
require 'gruff'
g = Gruff::Line.new
require 'rubygems' returns a fail, and require 'gruff' gives an error, but I can get it to just return false if I comment out the relevant line of code in the gruff source.
Anyhow, when I type g = Gruff::Line.new I get the this error:
NameError: uninitialized constant Gruff
which I presume is telling me that we have failed to pull in the gruff module - adjusting the capitalization is no help:
irb(main):004:0> g = gruff::Line.new
NameError: undefined local variable or method `gruff' for #<Object:0x2959258>
from (irb):4
The thing is I'm stuck as to how to proceed from here - is there some way for me to interogate the system so I can find out why the require 'gruff' is failing?
As I understand it my path is set up fine:
irb(main):005:0> $:
=> ["d:/ruby/lib/ruby/gems/1.8/gems/RMagick-win32-1.9.2-mswin32/bin", "d:/ruby/lib/ruby/ge
ms/1.8/gems/RMagick-win32-1.9.2-mswin32/lib", "d:/ruby/lib/ruby/gems/1.8/gems/gruff-0.0.6/
bin", "d:/ruby/lib/ruby/gems/1.8/gems/gruff-0.0.6/lib", "d:/ruby/lib/ruby/site_ruby/1.8",
"d:/ruby/lib/ruby/site_ruby/1.8/i386-msvcrt", "d:/ruby/lib/ruby/site_ruby", "d:/ruby/lib/r
uby/1.8", "d:/ruby/lib/ruby/1.8/i386-mswin32", "."]
i.e. i get all the above after entering the require commands, despite the fact that they return failures.
hmm, so actually writing all this out helped - as I just fixed the problem. It seems that I needed to restart irb each time I made modifications to the source code in order to see the continuing errors being generated after my modifications.
I was confused beacause after throwing an error once, a repeat call to require would just return false, without any error message. By restarting irb and seeing the addtional errors, I commented out a load of undef_method calls in rmagick.rb and now it all works.
Sometimes you just need to be able to explain these things to someone
Many thanks for your input
SAM
Robert Klemme wrote:
As far as I know there is no such comprehensive list (note, I may be wrong
here). But closely looking at the exception stack trace and the code it
points to you usually see what's wrong very fast.
Yuri Kozlov wrote:
···
NameError: uninitialized constant Blah
irb(main):002:0> x = My_case_is_wrong
NameError: uninitialized constant My_case_is_wrong
from (irb):2
irb(main):003:0>
usually, grep -r Blah you_program_dir
is make clear the situation.