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0 pointsitishappy1y ago0 comments

You'll be keeping a lot more info in your head with your approach. For instance, the following illegal states have legal representations in your system:

    (null, null)
    (result, new DivideByZeroException())

Hence your unhandled base case in the extension method. Sum types are a more accurate representation and more pleasant to use as a result.

(btw, you're looking through the Monads For The Rest Of Us tutorial, but the the State Monad For The Rest Of Us tutorial is the one linked to this thread)

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CharlieDigital1y ago

I don't see those as necessarily illegal states, but even so, it's not hard to handle by adding a third `Action` for it (I kept the example short and left the first `if` condition empty).

The second case, if there is an exception, it would be handled as such by simply switching the order of the `if` in the extension method. None of this seems confusing nor onerous in day-to-day use.

itishappyOP1y ago

What does it mean to receive both value and error in the context of division? What about neither?

The issue is not that they cannot be handled, it's that they can be. You included an entire extra branch and check for something that will never occur because they're legal values for your tuple type. I assume it'll be optimized out of this trivial example, but imagine writing a function to receive your tuple type in a codebase where you didn't create the tuple. ADTs prevent this entire worry because there is no way to represent illegal states.

CharlieDigital1y ago

    What does it mean to receive both value and error in the context of division? What about neither?

It's only "invalid" if you define it as such. We can state "if we receive neither, then this is the same as an error state". And "if we receive both, than an exception occurred and should be handled".

I don't see the issue?

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0 pointsitishappy1y ago0 comments

You'll be keeping a lot more info in your head with your approach. For instance, the following illegal states have legal representations in your system:

    (null, null)
    (result, new DivideByZeroException())

Hence your unhandled base case in the extension method. Sum types are a more accurate representation and more pleasant to use as a result.

(btw, you're looking through the Monads For The Rest Of Us tutorial, but the the State Monad For The Rest Of Us tutorial is the one linked to this thread)

0 comments

CharlieDigital1y ago

I don't see those as necessarily illegal states, but even so, it's not hard to handle by adding a third `Action` for it (I kept the example short and left the first `if` condition empty).

The second case, if there is an exception, it would be handled as such by simply switching the order of the `if` in the extension method. None of this seems confusing nor onerous in day-to-day use.

itishappyOP1y ago

What does it mean to receive both value and error in the context of division? What about neither?

CharlieDigital1y ago

    What does it mean to receive both value and error in the context of division? What about neither?

I don't see the issue?

3 more replies

j / k navigate · click thread line to collapse