New slices are relevant

[sonatard]

It is warned by the wsl if I declare a new slice before the range loop.
I expect it's not warned.

only one cuddle assignment allowed before range statement (wsl)

https://play.golang.org/p/VEpWPSRTNfj

func evenFilter(a*A) []int{
	slice := a.slice
	newSlice := make([]int, 0, len(slice))
	for _, v := range slice { /* only one cuddle assignment allowed before range statement (wsl) */

		if v % 2 == 0 {
			newSlice = append(newSlice, v)
		}
	}

	return newSlice
}

The following codes are uncomfortable.

func evenFilter(a*A) []int{
	newSlice := make([]int, 0, len(a.slice))

	for _, v := range a.slice {

		if v % 2 == 0 {
			newSlice = append(newSlice, v)
		}
	}

	return newSlice
}

func evenFilter(a*A) []int{
	slice := a.slice
	newSlice := make([]int, 0, len(slice))

	for _, v := range slice {

		if v % 2 == 0 {
			newSlice = append(newSlice, v)
		}
	}

	return newSlice
}

[bombsimon]

Thanks for the issue!

It's interesting that you say this because I think what you ended up with in your second example is more or less exactly what my intentions was with this linter, to end up with code like that. To me it reads like this:

• Create variables to use throughout the scope, a new slice
• Iterate over something, in this case the passed argument
• Return the new slice

The first example you have is the one with most questions about. For reference, it's discussed at least in #33 and #71. In addition to what's said in #71 I can add that the reason for this is that each block should be seen as its own operation and could potentially even be its own function. Consider functional languages such as Haskell or Elixir, they don't even have for loops but instead you would use a fold or a recursive function.

The only thing that I can think of that would support alternative solutions and is yet on the wish list is to allow to cuddle variables that are used anywhere in the block (but still as long as only one is cuddled). See #24 and #50. If those were to be implemented and set to true, this would be an alternative.

func evenFilter(a*A) []int{
	newSlice := make([]int, 0, len(a.slice))
	for _, v := range a.slice {
		if v % 2 == 0 {
			newSlice = append(newSlice, v)
		}
	}

	return newSlice
}

And this, although I don't see why one would assign a separate variable to only used it in len like that.

func evenFilter(a*A) []int{
	slice := a.slice

	newSlice := make([]int, 0, len(slice))
	for _, v := range slice {
		if v % 2 == 0 {
			newSlice = append(newSlice, v)
		}
	}

	return newSlice
}

So to sum it up, there will not be support to cuddle multiple statements before blocks because it's one of the core ideas to have each block separated. Although the possibility to cuddle variables above a block that's used somewhere within

[sonatard]

Thank you for your thoughtful commentary!
I understand your design and philosophy, looking forward to solve #24 and #50.