尺寸的类型定义(Type definition for dimensions)

尺寸的类型定义(Type definition for dimensions)

如何定义尺寸的类型？

你可以用另一种类型来定义类型吗？ （即一英寸是72个PostScript点）。 为维度单位创建新类型还有意义吗？

我已经看过其他类型单元的库，但我感兴趣的维度是：缩放点（最小，也许是Int？），点（65536缩放点），异食（12点）等。

How would one define a type for dimensions?

Can you define a type in terms of another type? (i.e. an inch is 72 PostScript points). Would it even make sense to make a new type for a dimension unit?

I've seen libraries for other kind of units, but the dimensions I'd be interested in are: scaled point (smallest, maybe Int?), point (65536 scaled points), pica (12 points), etc.

最满意答案

我认为这是幽灵类型可以帮助的地方。 尺寸包是开始了解它们的好地方。 代码是有识字的Haskell，非常易读，所以我建议阅读。

I think this is where phantom types can help. The dimensional package is a good place to start to understand them. The code is literate Haskell and very readable so I'd recommend reading through that.