Rust in 2018: easier to use

Re:Rust in 2018: easier to use by Shoothe on Sunday January 14, 2018 @05:30AM (#16143637)

It's interesting because when I read about how Rust can rewrite iterators code into more performant direct loops I thought about Joe's blog posts that mentioned the same efforts for .NET. Also Span<T>. It seems .NET will have similar abstractions like Rust (of course not all can be migrated).

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Re:Rust in 2018: easier to use by pygy_ on Sunday January 14, 2018 @03:57PM (#16146379)

LuaJIT does the same, down to an absurd level.

From the luafun library readme (which uses iterators under the hood):

https://github.com/luafun/luafun

————

> Let's see an example:

    > -- Functional style
    > require "fun" ()
    > -- calculate sum(x for x^2 in 1..n)
    > n = 100
    > print(reduce(operator.add, 0, map(function(x) return x^2 end, range(n))))
    328350

    > -- Object-oriented style
    > local fun = require "fun"
    > -- calculate sum(x for x^2 in 1..n)
    > print(fun.range(n):map(function(x) return x^2 end):reduce(operator.add, 0))
    328350

> Lua Fun takes full advantage of the innovative tracing JIT compiler to achieve transcendental performance on nested functional expressions. Functional compositions and high-order functions can be translated into efficient machine code. Can you believe it? Just try to run the example above with `luajit -jdump` and see what happens:

    -- skip some initilization code --
    ->LOOP:
    0bcaffd0  movaps xmm5, xmm7
    0bcaffd3  movaps xmm7, xmm1
    0bcaffd6  addsd xmm7, xmm5
    0bcaffda  ucomisd xmm7, xmm0
    0bcaffde  jnb 0x0bca0024        ->5
    0bcaffe4  movaps xmm5, xmm7
    0bcaffe7  mulsd xmm5, xmm5
    0bcaffeb  addsd xmm6, xmm5
    0bcaffef  jmp 0x0bcaffd0        ->LOOP
    ---- TRACE 1 stop -> loop

> The functional chain above was translated by LuaJIT to (!) one machine loop containing just 10 CPU assembly instructions without CALL.

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