Loops

Ref. WGR Chapter 6, Control-flow techniques

loop

@@@ ruby
loop do
  puts "All work and no play makes Jack a dull boy."
end

To get out, use break:

@@@ ruby
loop do
  puts "All work and no play makes Jack a dull boy."
  break if rand > 0.9
end

• Note: loop needs a do keyword
• That's because it's really an iterator

while

@@@ ruby
while rand < 0.9
  puts "All work and no play makes Jack a dull boy."
end

begin
  puts "All work and no play makes Jack a dull boy."
end while rand < 0.9

until

@@@ ruby
until rand > 0.9
  puts "All work and no play makes Jack a dull boy."
end

begin
  puts "All work and no play makes Jack a dull boy."
end until rand > 0.9

single-line versions

@@@ ruby
puts "All work etc." while rand < 0.9
puts "All work etc." until rand > 0.9

for

@@@ ruby
fruits = ["apple", "banana", "cherry"]
for f in fruits
  puts "I love #{f}!"
end