chomp - works in irb, not in program

[Peter Vanderhaden]

When I try to use chomp to get user input, I get this error:

private method `chomp' called for nil:NilClass (NoMethodError)

from d:/scripts/ruby/fix1.rb:82:in `run'
from d:/scripts/ruby/fix1.rb:128

When I use it in irb, however it works. Anyone have any ideas what I
might be missing here?
Thanks....

 

[Sebastian Hungerecker]

When I try to use chomp to get user input

You can't get user input with chomp. The only thing you get from chomp is a
version of the string you called it on with trailing character removed.

private method `chomp' called for nil:NilClass (NoMethodError)

Yes, there is no chomp method for nil. You need to call chomp on a String. If
you thought that you were calling it on a String, you were thinking wrong.
You should look into that.

 

[Douglas Greenshields]

How are you using it in the program? Are you using gets.chomp? Can you
show a code sample?

 

[Peter Vanderhaden]

Douglas,
Here's the method I'm using:

def checkChange
puts "Do you want to change something else (y/N): "
changeIt = gets.chomp
if changeIt =~ /^[yY]/
puts "Enter string to change: "
before = gets.chomp
puts "Enter new string: "
after = gets.chomp
puts "Global change? (N/y): "
global = gets.chomp
end
end # End checkChange method.

 

[Peter Vanderhaden]

Douglas:
I forgot to mention that the puts command outputs the prompt to the
screen, but the program never pauses to give the user a chance to enter
anything for an answer. I'm assuming that's why the .chomp part doesn't
work. The first thing I need to do is figure out why gets isn't causing
the program to pause to accept the user input.
Thanks,
PV

Douglas,
Here's the method I'm using:

def checkChange
puts "Do you want to change something else (y/N): "
changeIt = gets.chomp
if changeIt =~ /^[yY]/
puts "Enter string to change: "
before = gets.chomp
puts "Enter new string: "
after = gets.chomp
puts "Global change? (N/y): "
global = gets.chomp
end
end # End checkChange method.

How are you using it in the program? Are you using gets.chomp? Can you
show a code sample?

 

[Sebastian Hungerecker]

Douglas:
I forgot to mention that the puts command outputs the prompt to the
screen, but the program never pauses to give the user a chance to enter
anything for an answer.

Are you by any chance running the script with any command line arguments?
That would cause Kernel#gets to read from disk instead of from stdin which
might explain the behaviour you're experiencing.


HTH,
Sebastian

 

[Douglas Greenshields]

Yes, as you imply, it's an issue with gets, not with chomp. The method
you posted looks pretty textbook - if gets can work, then chomp will
work. For some reason it looks like gets is not pausing the script
application and just returning nil.

 

[Sebastian Hungerecker]

For some reason it looks like gets is not pausing the script
application and just returning nil.

gets is reading from the file, that's been passed as a command line argument,
and returning nil because it's empty.

 

[Peter Vanderhaden]

Sebastian,
Right you are! When I did the original post, I screwed it up. I know
chomp doesn't get user input, I was using it with gets, and it didn't
work. I've got to do a better job of proofreading before I hit submit.
Sorry!