Peaker · HackerTrans

And this is why they need human brains in The Matrix

A type-class or just a callback type, vs pattern-matching, yeah.

There's a huge advantage to not everything being async/await. Knowing exactly when you yield control can give you atomicity and more determinism for free.

Peaker

8 年前議論

Then what you have is not "anything". You have an expression problem:

Either each element has some "handler" that does the right thing for that data type.

Or you have a set of cases that each data can be, and you handle them all.

Neither is just "any type". And static types are very suitable to describe either.

Peaker

8 年前議論

Everything is of course possible, but at what cost?

In my experience, with large projects, you get to pick 2:

Dynamic typing Development velocity Reliability

I've seen multiple large projects grind to a near halt in their development speed, and I've seen some retain development speed, but unreliably crash after various changes.

UT coverage is expensive. System tests don't catch everything. Either you fear changes, and the system rots, or you work very slowly with coverage for everything.

Peaker

8 年前議論

When do you have lists of lists of elements of any type?

What can you even do given such a value?

Peaker

8 年前議論

That's great for functions you just wrote. It's not as great for functions you change in a large code base.

Peaker

8 年前議論

Rust is a great systems language.

When I write applications, I don't need a systems language, and Haskell is easier to use.

Also, Rust is a great imperative language, it's not as great as a functional language, and you can't reap the benefits of pure functional programming.

Peaker

8 年前議論

An average US citizen contributes far more to pollution than the average African or Asian.

Peaker

8 年前議論

There are various library-level implementations. Here's the first one that turned up on Google:

https://raw.githubusercontent.com/target/row-types/master/ex...

Peaker

8 年前議論

Haskell has reasonable implementations of row types as well.

Peaker

8 年前議論

Life on Earth started within a few hundred million years, not 2 billion years.

Peaker

8 年前議論

I suspect the problem is mentoring. It took me months to get basic Haskell.

The people I mentored, though, could clarify any misunderstanding and get explanations from multiple viewpoints from me -- after years of experience with these abstractions. With such mentoring, you don't have to go through all the confusion phases.

Peaker

8 年前議論

Haskell record syntax with lenses is workable:

  import Control.Lens

  data MyRecord = MyRecord { _a :: Int, _b :: MyRecord }
  makeLenses ''MyRecord

Then you can use it nested like:

  over (b . b . a) (+5) myRecord

Peaker

8 年前議論

I've mentored programmers in Haskell and they were also productive within a few weeks.

I'm pretty sure I could get a student to write useful Haskell code in that time span with just mentoring and existing documentation material.

Peaker

8 年前議論

That's the Maybe type. The Maybe monad is this:

  instance Monad Maybe where
    return = Just
    Nothing >>= _ = Nothing
    Just x >>= f = f x

(And is not really related to the discussion)

Peaker

8 年前議論

Destroying a language's safety for a single use case is a terrible trade-off.

There are various possible solutions for circular structures that do not require destroying all static safety with nulls everywhere.

Peaker

8 年前議論

Isn't the bottleneck in any sequential access case the memory bandwidth?

IOW: Are the scalar instructions slower than memory bandwidth?

Peaker

8 年前議論

Of course that's true. But Lisp is shitty at controlling memory use, indirections, and manual MM.

Peaker

8 年前議論

They're not really "inheritance". They can do what inheritance can do, and much much more.

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