goutils/containers/generics.go

package containers

type ChainElem[T any] struct {
	Elem *T
	Next *ChainElem[T]
}

// reachable checks if you can reach elem l when starting from elem f.
// It detects loops and returns false if it runs into one.
func reachable[T any](f, l *ChainElem[T]) bool {
	// Map to keep track of nodes already visited
	checks := make(map[*ChainElem[T]]bool)
	for w := f; w != l; w = w.Next {
		if w == nil {
			return false
		}
		// Shortcut: Maps where the value is bool have a default value of false
		// If a key doesn't exist yet the result will thus be false
		if checks[w] {
			return false
		}
		// Set the current elem to true to mark it as visited
		checks[w] = true
	}
	return true
}

// emptyElem creates a new ChainElem[T] with empty values.
func emptyElem[T any]() *ChainElem[T] {
	return &ChainElem[T]{
		Elem: nil,
		Next: nil,
	}
}