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Re: RE: Avoid Case Analyses

• From: John Cowan <cowan@mercury.ccil.org>
• To: "Costello, Roger L." <costello@mitre.org>
• Date: Tue, 9 Oct 2012 13:37:30 -0400

Costello, Roger L. scripsit:

>     Case analyses is essentially using examples to define a function (or
>      in the case of a specification to specify a behavior).

"Examples" usually means just a subset of the possible cases, whereas
"case analysis" involves specifying how to handle _every_ case.
Conflating them just produces confusion.

> "Programs that avoid case analyses are clearer and simpler than those
> that use case analyses."
> 
> Professor Richard Bird made that surprising statement in his book,
> Introduction to Functional Programming.

I can't find it using Amazon search within the book.  However, I think the
sense of "case analysis" in that book opposes it to "pattern matching",
which is a distinction that is only relevant to specific programming
languages that provide pattern matching.  The underlying implementation
is by an exhaustive set of cases anyway.

-- 
Even a refrigerator can conform to the XML      John Cowan
Infoset, as long as it has a door sticker       cowan@ccil.org
saying "No information items inside".           http://www.ccil.org/~cowan
        --Eve Maler

• Follow-Ups:
  • RE: RE: Avoid Case Analyses
    • From: David Lee <dlee@calldei.com>

• References:
  • Avoid Case Analyses
    • From: "Costello, Roger L." <costello@mitre.org>
  • RE: Avoid Case Analyses
    • From: "Costello, Roger L." <costello@mitre.org>