def assert( no, cond )
  if cond then
  else
    raise( 'assert ' + to_s(no) + ' failed' )
  end
end

assert( 1, concat(concat(concat('str=', 'a'), "b"), 'c') == 'str=abc' )
assert( 2, 'operator' + ' ok' == 'operator ok' )
assert( 3, 1 + 1 == 2 )
assert( 4, 4 * 1 + 10 * 1 == 14 )

if true then
  assert( 5, true )
else
  assert( 6, false )
end

i = 1
while i == 1 do
  i = false
end
assert( 7, i == false )
assert( 8, nil == nil )

def func
  assert( 9, true )
end
func

def argfunc( str )
  assert( 10, str == 'ok' )
end
argfunc 'ok'