How can I made this part of code from javascript to ruby? i would like to traslate from js to ruby this function:

    function* generate(arr) {
      console.log('AAAA'  arr)
        const A = Array.from(arr); // copy
  const len = A.length;
  const c = new Array(len).fill(0);
  let i = 0;
  yield A;
  while(i < len) {
    if(c[i] < i) {
      let j = i&1 ? c[i] : 0;
      if(A[i] != A[j]) {
        [A[j], A[i]] = [A[i], A[j]];
        yield A;
      }
      c[i]  ;
      i = 0;
    } else {
      c[i] = 0;
      i  ;
    }
  }
};

i am using like this that function:

function* definition(data) {
  const state = data.map(v => generate(v));

the console show me this:

AAAA1,1,1,2,1
AAAA3,2,4,4,4
AAAA6,6,7,8,7

I was trying this is my attempt:

def generate(arr)      
  a = arr.clone
  len = a.size
  c = new Array(len).fill(0)
  let i = 0
  yield a
  while i < len 
    if(c[i] < i) 
      let j = i&1 ? c[i] : 0
      if(a[i] != a[j]) 
        a[j], a[i] = [a[i], a[j]]
        yield a
      end
      c[i]  
      i = 0
    else 
      c[i] = 0
      i  
    end
  end
end

in ruby i am using like this:

 def definition(data)
      state = data.map { |v| generate(v) }

But I need a function* in ruby to create a generator.

also, this new Array(len).fill(0) is ok?

CodePudding user response：

generator = Enumerator.new do |yielder|
  5.times do
    5.times do |i|
      yielder << i
    end
  end
end

generator.to_a
# => [0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4, 0, 1, 2, 3, 4]
# Or use different methods from Enumerator or Enumerable
# Or make a function that returns this Enumerator for
# closest approximation of what you do with JS

In general, Ruby has no concept of * functions or async. You should think of them as if ALL Ruby functions were async and ALL calls were await. What this means is that unlike in JavaScript, in Ruby you can abort execution at any time, using a low-level interface of Fiber, or high-level abstractions like aforementioned Enumerator::Generator (created with Enumerator.new).

CodePudding user response：

Here JS generator function

function* generator() {
  let i = 0

  while (true) {
    yield i  
  }
}

gen = generator()

console.log(gen.next().value) // will print 0
console.log(gen.next().value) // will print 1
console.log(gen.next().value) // will print 2
// etc.

And here Ruby analogue to understanding

def generator
  Enumerator.new do |enum|
    i = 0

    loop do
      enum.yield i
      i  = 1
    end
  end
end

gen = generator

puts gen.next # will print 0
puts gen.next # will print 1
puts gen.next # will print 2
# etc.