类型转换

数字类型转换通过使用类型来执行：

var
  x: int32 = 1.int32   # 与调用int32(1)相同
  y: int8  = int8('a') # 'a' == 97'i8
  z: float = 2.5       # int(2.5)向下取整为2
  sum: int = int(x) + int(y) + int(z) # sum == 100