Path: g2news1.google.com!news3.google.com!news.glorb.com!border1.nntp.dca.giganews.com!nntp.giganews.com!local01.nntp.dca.giganews.com!nntp.comcast.com!news.comcast.com.POSTED!not-for-mail
NNTP-Posting-Date: Tue, 14 Jun 2005 04:29:56 -0500
Date: Tue, 14 Jun 2005 02:29:53 -0700
From: "Daniel C. Wang" <danwan...@gmail.com>
User-Agent: Mozilla Thunderbird 1.0 (Windows/20041206)
X-Accept-Language: en-us, en
MIME-Version: 1.0
Newsgroups: comp.lang.functional
Subject: Re: Ray tracer update
References: <42aca0a3$0$2039$ed2e19e4@ptn-nntp-reader04.plus.net> <d8jnt4$of7$1@oravannahka.helsinki.fi> <42adc234$0$2062$ed2e19e4@ptn-nntp-reader04.plus.net> <42AE46FC.5020109@gmail.com> <42ae4ca1$0$2995$ed2619ec@ptn-nntp-reader01.plus.net> <slrndat42k.4ia.wlovas@force.stwing.upenn.edu>
In-Reply-To: <slrndat42k.4ia.wlovas@force.stwing.upenn.edu>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Message-ID: <d4qdnRWXgoEJPjPfRVn-oQ@comcast.com>
Lines: 31
NNTP-Posting-Host: 24.16.88.182
X-Trace: sv3-aQS07ER3DeLrk4FOZmx+D6ohcM4JgPF6FluwGHk9phDeUydvXr+2aMZVJFJ+te2gDmfMyMqhYBPHWpO!GWh5SIO0XiRJQW/MVX+NQKrjxlMmJV4CXHuCsXRWQ+JCvuHMEsHyISk8PSuj2YJRRQOEtvMjbsGp
X-Complaints-To: abuse@comcast.net
X-DMCA-Complaints-To: d...@comcast.net
X-Abuse-and-DMCA-Info: Please be sure to forward a copy of ALL headers
X-Abuse-and-DMCA-Info: Otherwise we will be unable to process your complaint properly
X-Postfilter: 1.3.32

Now, I'm curious about this too.. because I do remember once stumbling 
upon this wart in Ocaml in the past...perhaps I'm confusing Caml with 
OCaml? Any Ocaml lurkers want to enlighten us. From what I remember 
there was some interaction with pattern guards that made the original 
match compiler not so useful in reporting non-exhaustive matches, was 
this fixed?

Anyway, I'm glad it was improved. :)
William Lovas wrote:
> On 2005-06-14, Jon Harrop <use...@jdh30.plus.com> wrote:
> 
>>Daniel C. Wang wrote:
>>
>>>I think this is a fair and common gripe. However, the SML match compiler
>>>is good at spotting errors when you confusing constructors. I find it
>>>unfortunate that the OCaml pattern match semantics aren't as strong as
>>>SML. In particular if I'm not mistaken it's impossible for Ocaml's match
>>>compiler to catch redundant or non-exhaustive matches.
>>
>>You mean non-exhaustive matches like this:
>>[...]
> 
> 
> Yeah -- where did this myth come from?  I'm pretty sure this isn't the
> first time i've heard it stated that O'Caml can't catch redundant or
> non-exhaustive patterns, but it's done both for as long as i've used the
> language (~5 years).  Were there earlier versions that famously couldn't?
> 
> In fact, while we're on the subject, notice how O'Caml even gives you an
> example of a pattern you've missed!  Oh, how i've wished SML/NJ would do
> that, instead of tell me all the ones i remembered *nudge*Matthias*nudge* ;)