Operations

An operation represents any kind of action or process.

An operation may:

• Use operands (things it acts upon)
• Produce a result or have side effects
• Be implemented as code (in programming), or occur in the real world (e.g., stacking boxes)

Examples:

• Walking is an operation without operands and without results (just motion).
• Cutting is an operation that uses operands and produces a result.
  • e.g., Cutting a pear (operand) → produces pear slices (result).

Operators

An operator is a special kind of operation that uses a symbol instead of a name to represent it.

• Common in both mathematics and programming.
• Operators always have a result.
• They typically act on one or more operands.
  • + is an operator for the addition operation.
  • *, /, -, ==, !, and so on.

Operators are the symbolic interface to operations.

Operands

An operand is a value or object that an operation or operator acts upon. Examples:

• In 2 + 3, both 2 and 3 are operands.
• In "cutting a pear", the pear is the operand.

Operations can sometimes become operands themselves.
Example: In f(g(x)), g(x) is a function invocation used as an operand for f.

In practice, since anything can become an operand for the right operation, operands are referred to as objects.