NOT.2:4.1 - Identify the expression constructors and their operands

Take the needed operation and distinctions from the working question or NOT.1. Describe the elementary expressions and the ways to construct a larger expression from them. For each construction, identify the required parts and what may occupy each place.

For example, a summation expression needs an index declaration, bounds and a body. A two-input transformation needs both inputs and a way to distinguish their roles. A repeated sequence needs a repeat count and the sequence being repeated. These are different constructors with different rules.

State the restrictions that the intended use needs. The restrictions may concern the kind of an operand, the number and order of connections, or a relation between component interfaces. Keep a missing part visible when partial construction is allowed. Identify the operation that requires the part to be supplied.