Operand

in programming languages

An argument of an operation; a grammatical construction signifying an expression that gives the value of the argument of an operation; sometimes the place or position in a text where the argument of an operation is to stand is called an operand. Hence the concept of arity of an operation, i.e. the number of arguments of an operation.

Depending on the position of the operand relative to the sign of the operation, one distinguishes between prefix (e.g. $\sin x$), infix (e.g. $a+b$) and postfix (e.g. $x^2$) operations. Dependent on the number of operands there are one-placed (unary or monadic), two-placed (binary or dyadic) and many-placed (or polyadic) operations.

In distinguishing between the position of the operand and the operand as an actual argument, the concept of transforming or coercing the operand to the form required by the operation arises. For example, if a real argument is situated in the position of an integer operand, the rules of the language may imply some method of rounding the real number to an appropriate natural number. Another example of coercion is variation of the form of the representation of an object, for example, a scalar is transformed to a vector consisting of one component.