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by MichaelGG 5702 days ago
I'm not familiar with python - does it have some magic global sentinel value to indicate "not found"? Or how do you handle that case with that 1 line of code?

Secondly, saying "it's still .NET" is similar to saying "it's still x64". The F# compiler does a lot of transforms on code that the C# compiler does not. In some cases, this can result in better IL and better JIT'd code. Also, having inlining support at the compiler level can be very handy sometimes.
2 comments
masklinn 5702 days ago
> I'm not familiar with python - does it have some magic global sentinel value to indicate "not found"?

No, it has a different method for failable search. The purpose of `get` is specifically to handle "provide a default value in case the key is not found".

> Or how do you handle that case with that 1 line of code?

dict[key]

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xiongchiamiov 5702 days ago
You can also use defaultdict[0], or define the __missing__() method[1] yourself on a dictionary you receive from someone else's code. In either of these cases the "not found" value will be whatever you decide it should be.

[0]: http://docs.python.org/library/collections.html#collections.... [1]: http://docs.python.org/library/stdtypes.html#dict

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fleitz 5702 days ago
Yes, good points MichaelGG, one of the really nice things about the F# compiler is that it can inline higher order functions, so if you pass a function to another it may create a custom piece of code with your passed function inlined. I wasn't sure if you were referring to C style inline support, which C# does have (in the .NET JIT). Like C the inlining in F# is just a suggestion to the compiler.

So you can write code that is optimal from a design point of view (abstractions, etc) and the compiler will turn it into optimal code from a performance point of view.

See http://flyingfrogblog.blogspot.com/2009/07/ocaml-vs-f-burrow... for a much better explanation.

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MichaelGG 5702 days ago
I don't think that F#'s inline is just a suggestion. Hat types (^a) aka statically resolved type variables, require inline methods to actually be inline. Same way you can't have inlined recursive functions.
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jdh30 5698 days ago
You can nest a recursive function inside a non-recursive one and inline that.
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