Option–operand separation

Option–operand separation is a principle of imperative computer programming. It was devised by Bertrand Meyer[1] as part of his pioneering work on the Eiffel programming language.

It states that an operation's arguments should contain only operands — understood as information necessary to its operation — and not options — understood as auxiliary information. Options are supposed to be set in separate operations.

The motivations for this are:

1. Ease of learning: Beginners do not have to concern themselves with setting options.
2. Wide spectrum coverage: Experts can still set options using the auxiliary operations.
3. Evolution. Options are more likely to change than operands, so the parameter list to the operation remains more stable.