Function initArrayElementConcatenation

pkg/sql/sem/tree/eval.go:249–272

TODO(justin): these might be improved by making arrays into an interface and then introducing a ConcatenatedArray implementation which just references two existing arrays. This would optimize the common case of appending an element (or array) to an array from O(n) to O(1).

()

// existing arrays. This would optimize the common case of appending an element
// (or array) to an array from O(n) to O(1).
func initArrayElementConcatenation() {
	for _, t := range types.Scalar {
		typ := t
		BinOps[Concat] = append(BinOps[Concat], &BinOp{
			LeftType:     types.MakeArray(typ),
			RightType:    typ,
			ReturnType:   types.MakeArray(typ),
			NullableArgs: true,
			Fn: func(_ *EvalContext, left Datum, right Datum) (Datum, error) {
				return AppendToMaybeNullArray(typ, left, right)
			},
		})

		BinOps[Concat] = append(BinOps[Concat], &BinOp{
			LeftType:     typ,
			RightType:    types.MakeArray(typ),
			ReturnType:   types.MakeArray(typ),
			NullableArgs: true,
			Fn: func(_ *EvalContext, left Datum, right Datum) (Datum, error) {
				return PrependToMaybeNullArray(typ, left, right)
			},
		})
	}
}

// ConcatArrays concatenates two arrays.
func ConcatArrays(typ *types.T, left Datum, right Datum) (Datum, error) {