Problem using back-ticks + eval

ruby-talk
1

Hi,

I'm trying to demo how Ruby handles various argument formats.

For example, I write the statement:
show %@`ruby DisplayArgs.rb Arg1 Arg2`@

and I get the output:
`ruby DisplayArgs.rb Arg1 Arg2`
=>
Arg[1]: "Arg1"
Arg[2]: "Arg2"

I'd like avoid having the back-ticks appear in the output. I'd like to
achieve this by moving the back-ticks from show invocation to show's
definition. In the following code, comments indicate what I tried, but
it failed.

Any ideas?

Thanks in Advance,
Richard

# ShowCmdLineArgs.rb
def show(stmt)
  print stmt
  puts "\n=> "
  eval("puts " + stmt).inspect # Put
back-ticks around "stmt"?
  puts
end

puts "\n========= Examples ========="
show %@`ruby DisplayArgs.rb Arg1 Arg2`@
show %@`ruby DisplayArgs.rb "Embedded "" quotes"`@ # Remove back-ticks
from this?

# DisplayArgs.rb
MAXARGS = 10
puts "No arguments" unless ARGV[0]
(0...MAXARGS).each { |i|
  break unless ARGV[i]
  print "Arg[#{(i+1).to_s}]: "
  puts ARGV[i].inspect
  puts "Quitting without inspecting addition arguments,
if any!" if i == MAXARGS-1
}

2

def show(command)
   puts command
   puts '=>'
   puts `#{command}`
end

···

On Jan 25, 2007, at 10:40, Richard wrote:

I'm trying to demo how Ruby handles various argument formats.

For example, I write the statement:
show %@`ruby DisplayArgs.rb Arg1 Arg2`@

and I get the output:
`ruby DisplayArgs.rb Arg1 Arg2`
=>
Arg[1]: "Arg1"
Arg[2]: "Arg2"

I'd like avoid having the back-ticks appear in the output.

--
Eric Hodel - drbrain@segment7.net - http://blog.segment7.net

I LIT YOUR GEM ON FIRE!

3

Hi Erik,

I was working in making "show" simpler, but I couldn't come up with
that last step. Beautiful.

Many thanks,
Richard

···

On Jan 25, 1:44 pm, Eric Hodel <drbr...@segment7.net> wrote:

On Jan 25, 2007, at 10:40, Richard wrote:

> I'm trying to demo how Ruby handles various argument formats.

> For example, I write the statement:
> show %@`ruby DisplayArgs.rb Arg1 Arg2`@

> and I get the output:
> `ruby DisplayArgs.rb Arg1 Arg2`
> =>
> Arg[1]: "Arg1"
> Arg[2]: "Arg2"

> I'd like avoid having the back-ticks appear in the output.def show(command)
   puts command
   puts '=>'
   puts `#{command}`
end

--
Eric Hodel - drbr...@segment7.net -http://blog.segment7.net

I LIT YOUR GEM ON FIRE!