Basic Difference between Proc and Lambda in Ruby

Proc => Proc  objects are blocks of code that have been bound to a set of local variables. Once bound, the code may be called in different contexts and still access those variables. <!--more--> {% codeblock lang:ruby%} myproc = proc do |a| puts "number is #{a}" end myproc.call(10 ) # number is 10 {% endcodeblock %} lambda {% codeblock lang:ruby%} mylambda = lambda do|a| puts "number is #{a}" end mylambda.call(10 ) # number is 10 {% endcodeblock %} Difference between both of themin Ruby-1.9.3

1. lambda is very specific for parameters passing to it but proc not -: {% codeblock lang:ruby%} myproc = proc do|a| puts "this is proc" end myproc.call #this is proc {% endcodeblock %} {% codeblock lang:ruby%} mylambda =lambda do |a| puts "this is lambda" end mylambda.call #will throw error "wrong number of arguments" {% endcodeblock %}

   In ruby-1.8.7 it just give you warning not error
   

2. Second is about return mean -: {% codeblock lang:ruby%} def runaproc(p) puts "starting proc" p.call puts "Ending proc" end

   def test_proc
     run_a_proc lambda{puts 'this is lambda'; return}
     run_a_proc proc{puts 'this is proc'; return}
   end
   test_proc
   {% endcodeblock %}
   the output is -:
   
   {% codeblock lang:ruby%}
   starting proc
   this is lambda
   Ending proc
   starting proc
   this is proc
   {% endcodeblock %}
   

so difference is lambda return within it but the proc return from where it is called if we modified test_proc method like

{% codeblock lang:ruby%} def testproc runaproc proc{puts 'this is proc'; return} runa_proc lambda{puts 'this is lambda'; return} end {% endcodeblock %} now the output will be -:

{% codeblock lang:ruby%} starting proc this is proc {% endcodeblock %}