simonpj at microsoft.com
Wed Jul 21 06:44:21 EDT 2004
I've fixed this now. Thanks for pointing it out.
| -----Original Message-----
| From: glasgow-haskell-users-bounces at haskell.org
| bounces at haskell.org] On Behalf Of Ian Lynagh
| Sent: 13 July 2004 15:43
| To: Simon Marlow
| Cc: glasgow-haskell-users at haskell.org; Peter Simons
| Subject: Re: "Stricts _"
| On Tue, Jul 13, 2004 at 03:16:39PM +0100, Simon Marlow wrote:
| > On 13 July 2004 15:02, Peter Simons wrote:
| > > ghci-6.3 (from CVS) shows me strictness information when I
| > > request :info for a data type, like:
| > >
| > > [...] Send Mailbox Stricts: _ [...]
| > >
| > > I have no idea how to read that output, and it doesn't seem
| > > to be documented in the manual either. Does the underscore
| > > signify that (in the example above) Mailbox is a strict
| > > value? Or is it the opposite?
| > >
| > > Sorry if this is a dumb question, but I simply don't know
| > > it. :-)
| > I don't think :info is working properly in the HEAD right now. It's
| > something we need to fix before 6.4. I suggest just ignoring the
| > spurious output for now.
| Based on ":info Maybe" and ":info Complex.Complex" the info looks
| to me, with _ meaning non-strict and ! meaning strict. Presumable you
| mean that it should print just "Send Mailbox" or "Send !Mailbox"? I
| assume this is just what you told GHC when you defined the type,
| rather than telling you anything about optimisations GHC has done.
| Also, it looks like :info doesn't work for tuples:
| Prelude> :info (,,)
| -- *** Exception: No match in record selector TyCon.algTyConRhs
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