R1100 - modelint/shlaer-mellor-metamodel GitHub Wiki

R1100 / 1:M

Computation processes one or many Operand

Operand is processed by exactly one Computation

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By definition, a Computation processes at least one and typically two inputs.

What about a generator function which requires no input, though? We know for example that we may use a function that generates new id values, for example. But such a function is not considered a Computation Action as defined in our metamodel. In the particular case of an id generator, that would typically be handled as a type selector or a type based function.

Computations should not be confused with methods, (domain) operations, or type operations. These are distinct Actions.

An Operand is defined within the context of a specific Computation Action. You could say that an Operand represents the requirement for a certian input to a Computation.