Difference between revisions of "Bounds checking"

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(the non-dependently typed bounds checking example)
(Deleting page that hasn't been updated for over 10 years)
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"There is a view that in order to gain static assurances such as an array index
being always in range or tail being applied to a non-empty list, we must give
up on something significant: on data structures such as arrays (to be replaced
with nested tuples), on general recursion, on annotation-free programming, on
clarity of code, on well-supported programming languages.
That does not have to be the case. [These exampels] show non-trivial
examples involving native Haskell arrays, index computations, and general
recursion. All arrays indexing operations are statically guaranteed to be safe
-- and so we can safely use an efficient unsafeAt provided by GHC seemingly for
that purpose. The code is efficient; the static assurances cost us no run-time
overhead. The example uses only Haskell98 + higher-ranked types. No new type
classes are introduced. The safety is based on: Haskell type system, quantified
type variables, and a compact general-purpose trusted kernel."
[http://okmij.org/ftp/Haskell/types.html#branding Eliminating Array Bound Checking through Non-dependent types]

Revision as of 14:47, 6 February 2021