sqWiki

#!/usr/bin/env ruby -wKU
 
def run_block
  p = Proc.new
  p.call
end
 
run_block do
  puts "Hi, Marek!"
end
 
# Output
Hi, Marek!

proc = Proc.new do |adjective|
  puts "Working with a Procs is #{adjective} pleasure!"
end
 
proc.call("great")
proc.("big")              # = proc.call("big")
proc["enormous"]
proc === "all"

welcome = proc do |a, b, c|
  puts "This is a proc"
end
 
welcome.call        # a, b i c ustawiane są jako nil
 
# Output
This is a proc
 
welcome = lambda do |a, b, c|
  puts "This is a lambda"
end
 
welcome.call
 
# Output
/Users/sqbell/Workspace/ruby/others/procs.rb:10:in `block in <main>': wrong number of arguments (0 for 3) (ArgumentError)
	from /Users/sqbell/Workspace/ruby/others/procs.rb:13:in `call'
	from /Users/sqbell/Workspace/ruby/others/procs.rb:13:in `<main>'

#!/usr/bin/env ruby -wKU
 
def run_a_proc(p)
  puts "Starting to run a proc."
  p.call
  puts "Finished running the proc.\n\n"
end
 
run_a_proc lambda { puts "I'm a lambda!"; return }
 
# Proc jest definiowany tutaj, czyli w głównym kontekscie
# a z głównego kontekstu nie można nic zwrócić
run_a_proc proc   { puts "I'm just a proc. :-("; return }
 
# Output
/Users/sqbell/Workspace/ruby/others/procs.rb:10:in `block in <main>': unexpected return (LocalJumpError)
  from /Users/sqbell/Workspace/ruby/others/procs.rb:5:in `call'
  from /Users/sqbell/Workspace/ruby/others/procs.rb:5:in `run_a_proc'
  from /Users/sqbell/Workspace/ruby/others/procs.rb:10:in `<main>'
Starting to run a proc.
I'm a lambda!
Finished running the proc.
 
Starting to run a proc.
I'm just a proc. :-(

#!/usr/bin/env ruby -wKU
 
def run_proc(p)
  p.call
end
 
name = "Marek"
 
print_a_name = proc { puts name }
 
name = "Krzysztof"
 
run_proc print_a_name
 
# Output
Krzysztof