Ruby instance_exec / instance_eval with arguments

Question

I'm trying to dynamically call a method given in a string using parameters given in the same string, I'm getting stuck on supplying the parameters though...

I currently have:

query = Query.new

while true
  input = gets.split(%r{[/[[:blank:]]/,]})
  puts (query.instance_exec(*input.drop(1)) { |x|
    instance_eval input.at(0)
  })
end

So the method name is input(0) and the arguments to this method are in the rest of input. Is there any way to call this method with those parameters?

What does your input string look like? I only ask because your regex looks a bit odd. — mu is too short
– mu is too short, Commented Dec 4, 2011 at 20:02
The string looks like method_name paramList where paramList is a variable number of parameters separated by either commas, whitespace or a mix of both. So the regex should decompose this into an array of the form [method_name, param1, param2, ...]. PS: it should actually be %r{[/[[:blank:]]/,]+} I fixed that in the mean time. — rvdp
– rvdp, Commented Dec 5, 2011 at 13:43

sawa · Accepted Answer · 2011-12-04 17:41:28Z

1

The method you are looking for is send. Its first argument will be the method, and the rest will be passed to that method.

query = Query.new
puts query.send(*gets.split(/\s+/)) while true

You can use while modifier.
Your regex looks complicated. I made it look simple.
Don't forget to use the splat operator *, which decomposes an array.

edited Dec 4, 2011 at 17:41

answered Dec 4, 2011 at 17:36

sawa

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