Error Messages/40742

Example error text

When Variable B was computed, it did not set the value of Variable A as a side-effect.

Cause

The above error would occur when Variable A is defined as:

ComputedBy(B)

This definition of A indicates that its value is set when B is computed. For this to happen, somewhere inside B's definition, it must assign a value to A. In other words, B's definition must somewhere contain:

A:=«expr»

When B does not assign to A, then this error occurs. A's definition as a ComputedBy(B) is essentially a contract saying that B must set its value as a side-effect -- B will also compute B's own value, of course.

Remedy

Either define A differently, or make sure that B assigns a value to A when it computes.

See Also

• ComputedBy
• Assignment Operator

Proposed revised message

Variable A is defined using ComputedBy(B), but B does not actually compute and assign a value to A.

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