# rescue and exceptions

script = "uts \"Hello there doody\""

# try/catch is begin/rescue
begin
  eval script
rescue SyntaxError, NameError
  # by default, the same implicit is used as in Perl
  exName = $!.class.name
  puts "Compilation failed: #{exName}: #{$!.to_s}"
rescue StandardError => err
  # We can supply the name instead :)
  exName = err.class.name
  puts "Standard error: #{exName}: #{$!.to_s}"
end

# finally is ensure
begin
  eval script
rescue SyntaxError, NameError => err
  puts "Compilation failed"
ensure
  puts "Cleaning up"
end

# The construct also supports 'else', which is executed between the main body,
# and the 'ensure', only if NO exception was thrown
begin
  # fix the script
  eval "p#{script}"
rescue SyntaxError, NameError => err
  puts "Compilation failed: #{err.class.name}: #{$!.to_s}"
else
  puts "Compilation succeeded"
ensure
  puts "Cleaning up"
end

# As that example showed, we can fix the broken script thanks to our vast experience
# with the way these things are implemented ;-) So why not account for this 'common
# error' by fixing and retrying the block?
begin
  eval script
rescue SyntaxError, NameError => err
  # prefix with 'p' if first char is different, then go back to start of block
  if script[0,1] != 'p'
    puts "Compilation failed: #{err.class.name}: Trying to fix script '#{script}'"
    script = "p#{script}" 
    retry
  end 
  
  # otherwise, fail
  puts "Compilation failed, even after fix: #{err.class.name}: #{$!.to_s}"
else
  puts "Compilation succeeded"
ensure
  puts "Cleaning up"
end