linear argument

theory A function argument which is used exactly once by the

function.

If the argument is used at most once then it is safe to

inline the function and replace the single occurrence of the

formal parameter with the actual argument expression. If the

argument was used more than once this transformation would

duplicate the argument expression, causing it to be evaluated

more than once.

If the argument is sure to be used at least once then it is

safe to evaluate it in advance (see strictness analysis)

whereas if the argument was not used then this would waste

work and might prevent the program from terminating.

(1994-11-03)