Function OperatorIsImmutable

pkg/sql/sem/tree/constant_eval.go:17–38

OperatorIsImmutable returns true if the given expression corresponds to a constant operator. Note importantly that this will return true for all expr types other than FuncExpr, CastExpr, UnaryExpr, BinaryExpr, and ComparisonExpr. It does not do any recursive searching.

(expr Expr)

// expr types other than FuncExpr, CastExpr, UnaryExpr, BinaryExpr, and
// ComparisonExpr. It does not do any recursive searching.
func OperatorIsImmutable(expr Expr) bool {
	switch t := expr.(type) {
	case *FuncExpr:
		return t.ResolvedOverload().Class == NormalClass && t.fn.Volatility <= volatility.Immutable

	case *CastExpr:
		v, ok := cast.LookupCastVolatility(t.Expr.(TypedExpr).ResolvedType(), t.typ)
		return ok && v <= volatility.Immutable

	case *UnaryExpr:
		return t.op.Volatility <= volatility.Immutable

	case *BinaryExpr:
		return t.Op.Volatility <= volatility.Immutable

	case *ComparisonExpr:
		return t.Op.Volatility <= volatility.Immutable

	default:
		return true
	}
}