Original-Via: uk.ac.nsf; Sat, 28 Sep 91 08:19:16 BST
There is a bug in the lex function (PreludeText, appendix A7).
Since '-' now is valid as the first symbol of an operator, it
follows that e.g. "->>" is an operator, even though "->" is
reserved (page 8). But the clause (page 110, line -13)
Original-Via: uk.ac.ox.prg; Mon, 23 Sep 91 14:38:38 BST
Here are two relatively straightforward extensions to the syntax that
might be worth considering for future versions of Haskell. Both are
straightforward to implement (I know because I've experimented with
adding them to Gofer).
EXTENDED
Welcome to the Haskell Mailing List.
This mailing list exists to promote technical discussion concerning
the Haskell language. The forum is informal, and is subscribed to by
the majority of the Haskell committee as well as man
Original-Via: uk.ac.nsf; Tue, 1 Oct 91 21:42:55 BST
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I tried to insert the Enum class (page 30) into the diagram
of numeric classes (figure 7, page 55), but got confused.
Every standard type in class Real is individually declared
to be an instance of Enum
Original-Via: uk.ac.st-and.cs; Sat, 28 Sep 91 14:29:42 BST
A minor point.
Since '<-' is not an operator should it be a reservedop (presumably the
reserved operators are a subset of the operators)? I suggest that '<-'
(but not '->') should be a special.
Tony
Original-Via: uk.ac.nsf; Wed, 2 Oct 91 03:29:59 BST
Original-Sender: [EMAIL PROTECTED]
I have a little problem in interpreting what an interface file means
under peculiar circumstances (maybe I havn't read the report enough).
Can the someone help me?
The following interface file:
inter
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Original-Via: uk.ac.nsf; Thu, 3 Oct 91 04:59:15 BST
If I have an interface
interface A where
data T = X | Y
and then do the following
module B where
import A hiding(T)
...
Does that mean that only the type is hidden, but not the constructors (X, Y)?
Or is it the same as
Original-Via: uk.ac.nsf; Fri, 4 Oct 91 12:40:45 BST
Those of you interested in using Gofer (my interpreter for a Haskell-like
functional programming language) will be pleased to know that it is now
available from a couple of sources:
By anonymous ftp:
file: ~ftp/pub/glasgow/gofer-2.20.1.
Original-Via: uk.ac.nsf; Wed, 9 Oct 91 00:46:11 BST
Two Haskell puzzles:
1) What are the values of [ maxint .. ]
and [ chr(127) .. ] in Haskell 1.1?
2) What should they be?
-- Mikael R.
Original-Via: uk.ac.nsf; Mon, 7 Oct 91 21:35:30 BST
Original-Sender: postmaster <[EMAIL PROTECTED]>
Well, I am ready to scream, so I appeal to the more knowledgable gurus
on the net. The problem: I am trying to change the Complex
definition in the prelude as follows: create a general class Comp
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Original-Via: uk.ac.nsf; Mon, 7 Oct 91 21:36:58 BST
| Date: Tue, 1 Oct 1991 17:46:05 +0100
| From: Mikael Rittri <[EMAIL PROTECTED]>
| Subject: Why can't Real be made a subclass of Enum?
|
| I tried to insert the Enum class (page 30) into the diagram
| of numeric classes (figure 7,
Original-Via: uk.ac.nsf; Wed, 9 Oct 91 11:45:55 BST
| I just received new revised "Haskell Report, Version 1.1". After looking at
| the new grammer, I was wondering what is meant by the productions for 'afunlhs'.
| For example, p.35 gives an alternative syntax for binding functional values to
|
Original-Via: uk.ac.nsf; Wed, 9 Oct 91 12:07:29 BST
I just received new revised "Haskell Report, Version 1.1". After looking at
the new grammer, I was wondering what is meant by the productions for 'afunlhs'.
For example, p.35 gives an alternative syntax for binding functional values to
infix op
Original-Via: uk.ac.nsf; Wed, 9 Oct 91 12:11:34 BST
| From: [EMAIL PROTECTED]
| Subject: Multiple implementations of classes
|
| Well, I am ready to scream, so I appeal to the more knowledgable gurus
| on the net. The problem: I am trying to change the Complex
| definition in the prelude a
Original-Via: uk.ac.nsf; Sun, 13 Oct 91 03:45:22 BST
Original-Sender: [EMAIL PROTECTED]
| Two Haskell puzzles:
|
| 1) What are the values of [ maxint .. ]
|and [ chr(127) .. ] in Haskell 1.1?
maxint : repeat _|_and['\127'..'\255'] ++ repeat _|_
| 2) What should they be?
|
| -- Mikae
is
mailing list please specify this in your request.
Note: if you have previously obtained our 1.1 release, the procedure
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Original-Via: uk.ac.st-and.cs; Tue, 15 Oct 91 10:17:24 BST
IS DEPENDENCY ANALYSIS WELL ENOUGH DEFINED?
1) When module A needs exported items from module B, it need only see its
interface for compilation of A to be carried out.
In fact an implementation of B need not exist yet.(section 5.1.1)
2)
Original-Via: uk.ac.ox.prg; Tue, 15 Oct 91 14:09:41 BST
| Tony Davie's remarks prompt me to ask: "Who needs mutually recursive modules
| anyway?". I've never missed the facility in Miranda and my programs
| are much the clearer for it --- module dependency diagrams with NO
| directed cycles ---
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Original-Via: uk.ac.ed.mrcvax; Tue, 15 Oct 91 11:25:31 BST
Tony Davie's remarks prompt me to ask: "Who needs mutually recursive modules
anyway?". I've never missed the facility in Miranda and my programs
are much the clearer for it --- module dependency diagrams with NO
directed cycles --- blis
Original-Via: uk.ac.st-and.cs; Tue, 15 Oct 91 14:54:37 BST
> > Tony Davie's remarks prompt me to ask: "Who needs mutually recursive modules
> > anyway?". I've never missed the facility in Miranda and my programs
> > are much the clearer for it --- module dependency diagrams with NO
> > dir
Original-Via: uk.ac.nsf; Tue, 15 Oct 91 14:44:45 BST
> Tony Davie's remarks prompt me to ask: "Who needs mutually recursive modules
> anyway?". I've never missed the facility in Miranda and my programs
> are much the clearer for it --- module dependency diagrams with NO
> directed cycles --- b
Original-Via: uk.ac.ed.mrcvax; Tue, 15 Oct 91 16:19:08 BST
| Our Haskell in Haskell compiler modules are often unavoidably mutually
| recursive. For small programs you may be right, but for large programs
| mutually recursive modules are almost inevitable:
|
| i)
Original-Via: uk.ac.ed.aiai; Tue, 15 Oct 91 17:08:55 BST
> | Our Haskell in Haskell compiler modules are often unavoidably mutually
> | recursive. For small programs you may be right, but for large programs
> | mutually recursive modules are almost inevitable:
> |
> | i)
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Original-Via: uk.ac.st-and.cs; Wed, 16 Oct 91 15:51:09 BST
There should be a comma after the word 'otherwise' in the exports list
of the Standard Prelude on p79
Tony Davie
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Original-Via: uk.ac.ed.aiai; Wed, 16 Oct 91 17:56:53 BST
> > > | Our Haskell in Haskell compiler modules are often unavoidably mutually
> > > | recursive. For small programs you may be right, but for large programs
> > > | mutually recursive modules are almost inevitable:
> > > |
> > > |
Original-Via: uk.ac.ed.aiai; Thu, 17 Oct 91 16:12:59 BST
> Mutual recursion is a natural part of functional programming style, and
> we shouldn't have to come up with special examples to justify its existence.
If it were equally natural in this case then I think the issue would
never have arisen
Original-Via: uk.ac.ed.dcs; Thu, 17 Oct 91 18:04:19 BST
(a general remark:)
The aim of modularisation is (mainly) to govern
in a divide-and-conquer way huge tasks.
What is _huge_ depends on the ability/taste/[insert your favourite ...]
of the humans having to deal with the task
(and sometimes ev
Original-Via: uk.ac.ed.aiai; Thu, 17 Oct 91 18:18:32 BST
> (a general remark:)
>
> The aim of modularisation is (mainly) to govern
> in a divide-and-conquer way huge tasks.
> What is _huge_ depends on the ability/taste/[insert your favourite ...]
> of the humans having to deal with the task
> (a
Original-Via: uk.ac.nsf; Fri, 18 Oct 91 05:18:44 BST
> The question here is whether a particular way of dividing tasks
> should be supported by a particular language mechanism. There
> are good (but perhaps not conclusive) arguments in favor of
> support for recursive modules. But "some things
Original-Via: uk.ac.st-and.cs; Fri, 18 Oct 91 09:25:44 BST
>All the messages pro and anti recursive modules are very interesting but
>my original question has been lost sight of. Are we meant to do
>dependency analysis across module boundaries or not? and if so can anyone
>se
Original-Via: uk.ac.nsf; Wed, 23 Oct 91 23:39:10 BST
What happens is you import a module, A, and it contains a value, say
x::T
and also a type synonym for T, say
type T = Int
but then you hide T on import. I.e.
import A hiding(T)
The type synonym T is not imported any othe
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Original-Via: uk.ac.nsf; Thu, 24 Oct 91 01:55:59 BST
What happens with the following program?
import Prelude hiding(Dialogue)
main _ = error "main"
Dialogue is not in the Core so it can be hidden, making main have an
unknown type.
-- Lennart
Original-Via: uk.ac.nsf; Thu, 24 Oct 91 22:15:31 BST
Hi,
Does anyone have a Haskell compiler for Sun 3's which supports the new "let"
syntax? I could easily add it to my own compiler, but my compiler has no type
checker at present (so no classes and no currying). My requirements are:
(1) Hask
Original-Via: uk.ac.nsf; Thu, 24 Oct 91 22:23:45 BST
Original-Sender: [EMAIL PROTECTED]
Lennart brings up some interesting points. What is at stake here is
the interpretation of the closure rule, Section 5.1.3. The question
needs to be a little more precise. Lennart's example is
What happens
Original-Via: uk.ac.st-and.cs; Fri, 25 Oct 91 13:01:49 BST
Original-Via:
1: The functions 'approximants' and 'partialQuotients' are exported
from module 'PreludeRatio' (see p94).
Should they appear in Figure 9, p58 together
with a description of what they do in section 6.8.3?
2: The module 'Pr
Original-Via: uk.ac.nsf; Fri, 25 Oct 91 18:27:51 BST
Original-Sender: [EMAIL PROTECTED]
John Peterson writes:
> import Prelude hiding(Dialogue)
> main _ = error "main"
>
> Actually I'm not sure how this program refers to 'Dialogue' at all.
Well, I quote from the Report (p. 40, lin
Original-Via: uk.ac.st-and.cs; Mon, 28 Oct 91 14:54:31 GMT
The functions toUpper and toLower in the standard prelude (p 80) have
initial definitions which should read:
toUpper c | isLower c = chr (ord c - (ord 'A' - ord 'a'))
and
toLower c | isUpper c = chr (ord c - (ord 'a' - ord 'A'))
Tony
Original-Via: uk.ac.nsf; Fri, 25 Oct 91 23:30:48 BST
Original-Sender: [EMAIL PROTECTED]
Lennart asks:
> import Prelude hiding(Dialogue)
> main _ = error "main"
>
> ... I quote from the Report (p. 40, line 8):
>
>..., and main must have type Dialogue.
>
>As far as I can understa
Original-Via: uk.ac.st-and.cs; Mon, 28 Oct 91 15:31:11 GMT
Oh * !!
Tony
Original-Via: uk.ac.st-and.cs; Wed, 30 Oct 91 17:05:34 GMT
It seems to me that some of the most useful arithmetic divide and
conquer algorithms express a function of an integer n in terms of
the same function applied to n `div` 2. Has any thought been given to
generalising n+k patterns to c*n+k p
Original-Via: uk.ac.ic.doc; Mon, 28 Oct 91 15:16:11 GMT
Tony Davie <[EMAIL PROTECTED]> wrote:
>The functions toUpper and toLower in the standard prelude (p 80) have
>initial definitions which should read:
>
>toUpper c | isLower c = chr (ord c - (ord 'A' - ord 'a'))
>
>and
>
>toLower c | isUpper c
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Original-Via: uk.ac.earn-relay; Tue, 29 Oct 91 12:05:25 GMT
X-Acknowledge-To:
Dear collegaugs,
I am from the Department of Computers
Czech Technical University Prague.
We are preparing an update of our
functional programmnig course and we
think that Haskell should be thaught here.
We have got th
Original-Via: uk.ac.st-and.cs; Thu, 17 Oct 91 09:45:57 BST
All the messages pro and anti recursive modules are very interesting but
my original question has been lost sight of. Are we meant to do
dependency analysis across module boundaries or not? and if so can anyone
see how to?
Tony Davie
#
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>From haskell-request Wed Oct 16 18:01:26 1991
Original-Via: uk.ac.ed.aiai; Wed, 16 Oct 91 17:56:53 BST
Date: Wed, 16 Oct 91 17:58:20 BST
Message-Id: <[EMAIL PROTECTED]>
From
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Original-Via: uk.ac.nsf; Fri, 1 Nov 91 01:19:12 GMT
Simon says:
This is certainly technically feasible. As it happens, our compiler is set
up so that it is easy to compile any pattern which you can express as a
predicate function ("does it match?") plus an extract-binder
Original-Via: uk.ac.st-and.cs; Fri, 1 Nov 91 09:37:40 GMT
Brian says there are two distinct problems with n+k patterns,
1) That laws relating * `div` `rem` + - might not hold.
2) A user defined >= might not be strict giving rise to a match
of bottom to a refutable patt
Original-Via: uk.ac.st-and.cs; Fri, 1 Nov 91 09:49:13 GMT
It has been pointed out to me by the Yale implementers
that the expression a*b/c causes a parse error because / is infix
rather than infixl and is of the same precedence (7) as * which IS
infixl.
Is this an oversight of someone on the com
Original-Via: uk.ac.ed.mrcvax; Fri, 1 Nov 91 14:00:30 GMT
> | Which leads me to one final comment. Does the Report say anywhere that
> | an overflow gives rise to an undefined result?
>
> Yes it does (though you may not like the answer!). See Section 6.8.1, p56.
>
> Simon
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Original-Via: uk.ac.ed.mrcvax; Fri, 1 Nov 91 10:03:45 GMT
| Which leads me to one final comment. Does the Report say anywhere that
| an overflow gives rise to an undefined result?
|
| Tony
Good question! I think it should, though I fear the efficiency implications.
Ian
Original-Via: uk.ac.ox.prg; Fri, 1 Nov 91 18:04:12 GMT
Brian Boutel writes:
| With Haskell as it is currently defined, one can take an operational view,
| that the syntactic translation given in the report defines the semantics
| of n+k patterns, and too bad if the semantics of the introduced f
Original-Via: uk.ac.nsf; Mon, 4 Nov 91 11:35:00 GMT
> Incidentally, I'd suggest that we have separate (c*n) and (n+k) forms of
> pattern ... extending the syntax of patterns to:
>
> pat ::= | int * pat | pat + k
>
> This would allow c*n+k patterns as a special case, but also
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Original-Via: uk.ac.ox.prg; Mon, 4 Nov 91 13:52:20 GMT
Kent Karlsson asks:
| Which semantics did you use?
The following seemed sensible to me (Your first choice in each case):
For p+k patterns: (as in the report):
case e0 of {p+k -> e; _ -> e'}
= if e0 >= k then let {p = e0-k}
Original-Via: uk.ac.nsf; Tue, 5 Nov 91 02:56:42 GMT
Original-Sender: [EMAIL PROTECTED]
Tony writes:
It has been pointed out to me by the Yale implementers
that the expression a*b/c causes a parse error because / is infix
rather than infixl and is of the same precedence (7
Original-Via: uk.ac.ed.mrcvax; Mon, 4 Nov 91 17:16:03 GMT
Original-Via: talisker.hgu; Mon, 4 Nov 91 17:15:05 GMT
| > "The results of exception conditions (such as overflow or underflow) on
| > the fixed-precision numeric types are undefined; and implementations
| > may choose er
Original-Via: uk.ac.nsf; Tue, 5 Nov 91 03:07:23 GMT
Original-Sender: [EMAIL PROTECTED]
I just sent an errata list to Will Partain, including the following:
>2) Nowhere does the Report say that if a type is an instance of a class
>then it must also be an instance of all that class's superclasses.
Original-Via: uk.ac.nsf; Mon, 4 Nov 91 17:00:37 GMT
> Kent Karlsson asks:
> | Which semantics did you use?
>
> The following seemed sensible to me (Your first choice in each case):
There was no ranking!
>
> For p+k patterns: (as in the report):
> case e0 of {p+k -> e; _ -> e'
Original-Via: uk.ac.ox.prg; Tue, 5 Nov 91 16:46:19 GMT
I'm a little bit bothered about the approach to defining orderings on
elements in the way suggested by the Haskell report and by the definitions
in the standard prelude. I'm sending this to the Haskell list in the hope
that somebody can sugg
Original-Via: uk.ac.ox.prg; Tue, 5 Nov 91 17:19:00 GMT
A slight correction to my previous message .. the basic intuition for
comp should have been:
comp x y o | "x is less than y" = LT
| "x is equal to y" = o
| "x is greater than y"
Original-Via: uk.ac.ed.dcs; Tue, 5 Nov 91 18:30:59 GMT
There were two small bugs in the solution of Mark Jones:
1) To avoid multiple traversal of data, comp needs to stop
to traverse data, if a non-EQ value has been found.
Hence the intuition behind comp should be rather
comp x y EQ | "x i
Original-Via: [+JANET.711400.23429052424290/ftp.mail]; Tue, 5 Nov 91 09:35:59
GMT
wrt Float/Real operations: I suggest you look at the notion of exactness
in Scheme, which effectively allows one to distinguish between when numbers
must behave mathematically, and when close is good enough
Original-Via: uk.ac.nsf; Tue, 5 Nov 91 21:21:39 GMT
| Date:Fri, 25 Oct 91 12:12:35 +
| From:Tony Davie <[EMAIL PROTECTED]>
| To: haskell
| Subject: modules in the report
|
| 1: The functions 'approximants' and 'partialQuotients' are exported
| from module 'PreludeRatio' (see p94)
Original-Via: uk.ac.nsf; Tue, 5 Nov 91 21:15:51 GMT
| From: Tony Davie <[EMAIL PROTECTED]>
| Subject: fixity of /
|
| It has been pointed out to me by the Yale implementers
| that the expression a*b/c causes a parse error because / is infix
| rather than infixl and is of the same precedence
Original-Via: uk.ac.nsf; Wed, 6 Nov 91 14:43:35 GMT
Original-Sender: [EMAIL PROTECTED]
1. On p. 57, middle of figure 8 it says:
x `mod` y = if signum x == -(signum y) ...
it should be:
x `mod` y = if signum r == -signum y ...
^
(as it is
Original-Via: uk.ac.nsf; Tue, 5 Nov 91 21:31:13 GMT
Original-Sender: [EMAIL PROTECTED]
Mark says:
This problem isn't just restricted to pattern matching ...
I'm interested in the assumptions that an implementation can legitimately
make about the way overloaded functions behave. Other no
Original-Via: uk.ac.ox.prg; Wed, 6 Nov 91 09:30:57 GMT
[EMAIL PROTECTED] writes:
| There were two small bugs in the solution of Mark Jones:
No, I think they were Ok (after my slight correction).
But I can see why it might look confusing at first -- we naturally tend
to think of functional
Original-Via: uk.ac.ox.prg; Wed, 6 Nov 91 11:44:16 GMT
> | Kent Karlsson asks:
> | | Which semantics did you use?
> |
> | The following seemed sensible to me (Your first choice in each case):
>
> [ ... my attempt at a semantics for c*p and p+k patterns ... ]
>
>I had hoped not, since t
Original-Via: uk.ac.st-and.cs; Wed, 6 Nov 91 14:54:59 GMT
> > | Kent Karlsson asks:
> > | | Which semantics did you use?
> > |
> > | The following seemed sensible to me (Your first choice in each case):
> >
> > [ ... my attempt at a semantics for c*p and p+k patterns ... ]
> >
> >
Original-Via: uk.ac.nsf; Sat, 9 Nov 91 15:06:07 GMT
Original-Sender: [EMAIL PROTECTED]
I'm sorry if this is old news, but I just ran across what seems to be
a gratuitous loss of polymorphism in the transformational
specification of as-pattern binding in Haskell 1.1.
The problem is the lambda-exp
Original-Via: uk.ac.nsf; Wed, 6 Nov 91 20:00:39 GMT
Original-Sender: [EMAIL PROTECTED]
> I would be very much in favour of missing out the >= test in both n+k and
> c*n+k. As Mark says there is no need for a restriction in the latter case.
> In the former, the restriction is only there because o
Original-Via: uk.ac.nsf; Sat, 9 Nov 91 15:09:09 GMT
| Date: Fri, 8 Nov 1991 18:20:38 EST
| From: john peterson <[EMAIL PROTECTED]>
| Subject: Superclass instances (Oops)
|
| I'll still stick with my opinion on this one, though. Here's more
| reasons:
|
| a) This represents a poten
Original-Via: uk.ac.nsf; Sun, 10 Nov 91 16:03:39 GMT
Original-Sender: [EMAIL PROTECTED]
From: [EMAIL PROTECTED]
| From: john peterson <[EMAIL PROTECTED]>
| I'll still stick with my opinion on this one, though. Here's more
| reasons:
| a) This represents a potentially large numb
Original-Via: uk.ac.nsf; Sun, 10 Nov 91 07:55:42 GMT
Paul Hudak writes:
I don't understand your example.
That's because it's *wrong*! I was obviously thinking of Haskell 2,
where the relaxation of the C-T rule allows me to put instance
declarations somewhere besides the defining modules of th
Original-Via: uk.ac.nsf; Sun, 10 Nov 91 18:58:02 GMT
I was originally going to stay out of this one, but here's why I'm
voting for explicit superclass declarations.
The problem I see is that allowing implicit class declarations is
bound to cause confusion when a user does not actually see an ent
Original-Via: uk.ac.nsf; Sun, 10 Nov 91 02:23:26 GMT
a) If an instance declaration is given for a type T and class C, instance
declarations must also be given for T and all the superclasses of C.
b) If an instance declaration is given for a type T and class C, T is
automatically an i
Original-Via: uk.ac.st-and.cs; Wed, 13 Nov 91 16:58:45 GMT
The operator which was called `in` in version 1.0 seems to have
vanished without trace since `in` became a reservedid. Can I suggest
it be restored to PreludeList, possibly with the name `contains`:
contains :: (Eq a) => [a] -> a -> Bool
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Original-Via: uk.ac.nsf; Fri, 15 Nov 91 20:43:50 GMT
Has anyone looked at the complexity of type inference in Haskell
(similar to analogous results for ML)? Nipkow and Snelting have shown
how to reduce the inference problem to order-sorted unification (FPCA'91)
and they point out that such unifi
Original-Via: uk.ac.nsf; Sat, 16 Nov 91 09:47:52 GMT
The operator which was called `in` in version 1.0 seems to have
vanished without trace since `in` became a reservedid. Can I suggest
it be restored to PreludeList, possibly with the name `contains`:
contains ::
Original-Via: uk.ac.nsf; Sat, 23 Nov 91 08:53:36 GMT
I am confused about the meaning of constraints imposed by a context.
I will try to illustrate my understanding with an example. I am hoping that
the Gurus will either confirm or give another explanation.
Suppose I define
f x y z = if
[transferring over to the haskell list ...]
(After being surprised by a type error from writing "ppInt -42"...)
I allegedly wrote:
I reckon -42 should be a lexeme. If someone wants the bizarre business
above, they can write -(42).
Brian Boutel responded
Original-Via: uk.ac.nsf; Tue, 26 Nov 91 02:54:29 GMT
If I have understood you correctly, there is not a problem.
If there is an instance declaration for class C and type T, it must occur
either in the module that declares C or the module that declares T, and is
exported whenever C or T is expor
Original-Via: uk.ac.ox.prg; Mon, 25 Nov 91 18:31:48 GMT
[My apologies to those who receive this message from more than one source.
In future, messages about new versions of Gofer will be sent to those
people on the Gofer mailing list, and will not normally be duplicated in
other places.]
A new v
Original-Via: uk.ac.nsf; Wed, 27 Nov 91 01:09:30 GMT
Hi,
I have a copy of the Haskell 1.1 report, except for the first ten pages or so
which our LaserWriter refused to print (probably a dvi2ps problem).
Anyway, how should I cite it correctly? (bibTeX entry preferred)
Is it to appear in a well
Original-Via: uk.ac.nsf; Wed, 27 Nov 91 01:14:42 GMT
Hello again,
Can anyone help fill in the missing details for this bibTeX entry? I have my
own copy of this paper but I forgot to write the conference name on the first
page. I may have copied it from one of the LNCS series.
@inproce
Original-Via: uk.ac.st-and.cs; Wed, 27 Nov 91 11:41:37 GMT
Mark Jones sent me a message which included this:
-- PS. While I'm writing to you, can I ask about your other examples for
-- using c*n+k patterns? I like the examples you gave, but can't think of
-- too many other applications. If y
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