Renamed package 'greg' to 'regex'

regex/sliceQueue.go

@@ -0,0 +1,28 @@
+package regex
+
+import "errors"
+
+// Helper functions for slices, to make them behave more like stacks
+func peek[T any](s []T) (T, error) {
+	if len(s) < 1 {
+		return *new(T), errors.New("stack empty")
+	}
+	return s[len(s)-1], nil
+}
+
+func mustPop[T any](sp *[]T) T {
+	val, err := pop(sp)
+	if err != nil {
+		panic(err)
+	}
+	return val
+}
+
+func pop[T any](sp *[]T) (T, error) {
+	if len(*sp) < 1 {
+		return *new(T), errors.New("stack empty")
+	}
+	to_return := (*sp)[len(*sp)-1]
+	*sp = (*sp)[:len(*sp)-1]
+	return to_return, nil
+}