Replace most functionality in internal/util with goutil and slices

internal/util/util.go

@@ -1,100 +1,6 @@
 package util
 
 import "io"
-import "image/color"
-
-// IndexOf returns the index of needle within haystack. If needle does not exist
-// within haystack, it returns -1.
-func IndexOf[T comparable] (haystack []T, needle T) int {
-	for index, test := range haystack {
-		if test == needle {
-			return index
-		}
-	}
-	return -1
-}
-
-// Remove removes an element from slice at index.
-func Remove[T any] (slice []T, index int) []T {
-	return append(slice[:index], slice[index + 1:]...)
-}
-
-// Insert inserts an element into slice at index.
-func Insert[T any] (slice []T, index int, element T) []T {
-	slice = append(slice[:index + 1], slice[index:]...)
-	slice[index] = element
-	return slice
-}
-
-// Transparent returns whether or not a color has transparency.
-func Transparent (c color.Color) bool {
-	_, _, _, a := c.RGBA()
-	return a != 0xFFFF
-}
-
-// Set is a set of unique items, built on top of map.
-type Set[T comparable] map[T] struct { }
-
-// Empty returns true if there are no items in the set.
-func (set Set[T]) Empty () bool {
-	return set == nil || len(set) == 0
-}
-
-// Has returns true if the set contains item.
-func (set Set[T]) Has (item T) bool {
-	if set == nil {
-		return false
-	}
-	_, ok := set[item]
-	return ok
-}
-
-// Add adds an item to the set.
-func (set Set[T]) Add (item T) {
-	set[item] = struct { } { }
-}
-
-// Pop removes the first accessible item from the set and returns it.
-func (set Set[T]) Pop () (item T) {
-	for item := range set {
-		delete(set, item)
-		return item
-	}
-	return
-}
-
-// Memo holds a cached value.
-type Memo[T any] struct {
-	cache  T
-	valid  bool
-	update func () T
-}
-
-// NewMemo creates a new Memo which will take its value from the specified
-// update callback.
-func NewMemo[T any] (update func () T) Memo[T] {
-	return Memo[T] {
-		update: update,
-	}
-}
-
-// Value returns the Memo's value, updating it if the current cached value is
-// invalid.
-func (this *Memo[T]) Value () T {
-	if !this.valid {
-		this.cache = this.update()
-		this.valid = true
-	}
-	return this.cache
-}
-
-// Invalidate marks the Memo's value as invalid, which will cause it to be
-// updated the next time Value is called.
-func (this *Memo[T]) Invalidate () {
-	var zero T
-	this.cache = zero
-	this.valid = false
-}
 
 // Cycler stores a value and an accompanying io.Closer. When the value is set,
 // the closer associated with the previous value is closed.
@@ -124,33 +30,3 @@ func (this *Cycler[T]) Close () error {
 	this.closer = nil
 	return err
 }
-
-// Optional is an optional value.
-type Optional[T any] struct {
-	value T
-	exists bool
-}
-
-// Value returns the value and true if the value exists. If not, it returns the
-// last set value and false.
-func (this *Optional[T]) Value () (T, bool) {
-	return this.value, this.exists
-}
-
-// Set sets the value.
-func (this *Optional[T]) Set (value T) {
-	this.value = value
-	this.exists = true
-}
-
-// Unset unsets the value.
-func (this *Optional[T]) Unset () {
-	var zero T
-	this.value = zero
-	this.exists = false
-}
-
-// Exists returns if the value is currently set.
-func (this *Optional[T]) Exists () bool {
-	return this.exists
-}