e.And[0].Condition[0].Not != nil ||
		e.And[0].Condition[0].Operand.ConditionRHS != nil {
		return "", false
	}

	operand := e.And[0].Condition[0].Operand.Operand
	if operand.Right != nil ||
		operand.Left.Right != nil ||
		operand.Left.Left.Negated != nil ||
		operand.Left.Left.Primary.JPathExpr == nil {
		return "", false
	}

	// Check if path expression ends in a key

		maxl := xfixl
		if strl < maxl {
			maxl = strl
		}
		// compare letters
		if pre {
			// prefix, iterate left to right
			for i := 0; i < maxl; i++ {
				if xfix[i] != str[i] {
					xfix = xfix[:i]
					break
				}
			}
		} else {
			// suffix, iterate right to left
			for i := 0; i < maxl; i++ {
				xi := xfixl - i - 1
				si := strl - i - 1
				if xfix[xi] != str[si] {