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From: dale@cs.rmit.edu.au (Dale Stanbrough)
Subject: Re: Assertions
Date: 1999/05/17
Message-ID: <dale-1705991202350001@dale.bu.cs.rmit.edu.au>#1/1
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Date: 1999-05-17T02:02:35+00:00
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Nick Roberts wrote:

" 1. There's no reason why the compiler should not be able to assume that any
  assertion's condition holds true"


But of course there is the rub - I certainly don't want this to be true
-all the time-. 

I want some assertions to be genuinely tested, while others to be used
as an adjunct to the type system (and thus the compiler can use it for
optimisation purposes).

E.g. an assertion that a cached bill-of-materials total cost is indeed
the sum of all it's line items is something i want checked, whereas an
assertion that "this pointer is a linear pointer type" (i think that's
the notation that Henry Baker uses to describe linear dynamic data
structures) would be a useful way to give info to the compiler, but 
extremely expensive (if indeed possible) to test.


Dale