Proc behavior

procs.rb

# Proc behavior in reply to https://gist.github.com/jcoglan/0a37aee2582877b27920

def foo(&block)
  p [:foo, 1]
  puts "block returns " + block.call.inspect
  p [:foo, 2]
end

def bar(&block)
  p [:bar, 1]
  foo(&block)
  p [:bar, 2]
end

def baz
  p [:baz, 1]
  puts "bar returns " + bar {
    puts "always here"
    next
    raise "never happens"
  }.inspect
  p [:baz, 2]
end

baz
# =>
# [:baz, 1]
# [:bar, 1]
# [:foo, 1]
# always here
# block returns nil
# [:foo, 2]
# [:bar, 2]
# bar returns [:bar, 2]
# [:baz, 2]

puts "========================================================================"

def baz_next_with_value(value)
  p [:baz, 1]
  puts "bar returns " + bar {
    puts "always here"
    next value
    raise "never happens"
  }.inspect
  p [:baz, 2]
end

baz_next_with_value("the value")
# =>
# [:baz, 1]
# [:bar, 1]
# [:foo, 1]
# always here
# block returns "the value"
# [:foo, 2]
# [:bar, 2]
# bar returns [:bar, 2]
# [:baz, 2]

puts "========================================================================"

def baz_next_with_break(value)
  p [:baz, 1]
  puts "bar returns " + bar {
    puts "always here"
    break value
    raise "never happens"
  }.inspect
  p [:baz, 2]
end

baz_next_with_break("the value")
# =>
# [:baz, 1]
# [:bar, 1]
# [:foo, 1]
# always here
# bar returns "the value"
# [:baz, 2]