I have been following the recent discussions on "literate style" of
programming and I fail to see the purpose of making this part of the
language. As Mr. Dalton suggested, a preprocessor to separate code lines
from literate lines can easily be written. But I think this should be a
agreed upon
Original-Via: uk.ac.ed.aiai; Tue, 4 Feb 92 17:26:28 GMT
I think people are asking too much of a literate style. In my
opinion it is useful when writing programs with more comments than code.
In such situations, it is important to be able to distinguish comment lines
and code lines without
Original-Via: uk.ac.ed.mrcvax; Tue, 4 Feb 92 18:37:31 GMT
When programming in Miranda, I almost always produce a literate script,
which doubles as a LaTeX document. I think it would be sad if
Haskell did'nt define a literate style.
Ian
Original-Via: uk.ac.durham; Mon, 3 Feb 92 10:37:28 GMT
I think people are asking too much of a literate style. In my
opinion it is useful when writing programs with more comments than code.
In such situations, it is important to be able to distinguish comment lines
and code lines without having
Original-Via: uk.ac.nsf; Sun, 2 Feb 92 00:18:29 GMT
A personal opinion about this 'literate' feature;
I have done my thesis programming part in Miranda,
which has the same 'literate' option ( lines beginning with
are in the program, the other lines are comments ), and
I found it very
Original-Via: uk.ac.nsf; Thu, 30 Jan 92 23:14:16 GMT
A personal opinion about this 'literate' feature;
I have done my thesis programming part in Miranda,
which has the same 'literate' option ( lines beginning with
are in the program, the other lines are comments ), and
I found it very useful
Original-Via: uk.ac.nsf; Thu, 30 Jan 92 22:13:52 GMT
Original-Sender: [EMAIL PROTECTED]
Here are three decisions regarding recent syntax issues. Please let's
not discuss them any further for now unless you are absolutely
convinced that something terribly wrong is happening. An overriding
Original-Via: uk.ac.st-and.cs; Wed, 29 Jan 92 12:57:04 GMT
Should we rush into this? Kent's problem, although solved by Phil, convinces
me that there may be more to discuss about this subject. I suggest leaving
out literate comments until 1.3 or 2.0 or whatever the next version will be
called.
Kent inquires about the following program:
| This is a 'literate' Haskell comment line.
| {- This is an illiterate (?? :-) Haskell comment line, but where does it end?
| -- This question sounds familiar, but then no
| -- """literate""" programming was involved.
| -}
| Still in a
Original-Via: uk.ac.nsf; Wed, 29 Jan 92 15:14:28 GMT
John Peterson writes:
I was planning to stand aside on syntax issues, but this is going too far!
Simon proposes:
the back-quote stuff in the lexical syntax,
and the paren-ifying in the ordinary syntax.
| Should we rush into this? Kent's problem, although solved by Phil,
| convinces me that there may be more to discuss about this subject. I
| suggest leaving out literate comments until 1.3 or 2.0 or whatever the
| next version will be called. -- Tony
| Maybe we need a "how to be a good Haskell
Original-Via: uk.ac.nsf; Thu, 30 Jan 92 00:30:12 GMT
Since no one has argued against making Real a subclass of Enum
and Integer a subclass of Ix (see my previous letter), I assume
that everyone agrees with me. ;-)
-- Mikael R.
P.S: Here are some errata in 1.2.beta, with suggested fixes.
Original-Via: uk.ac.uknet; Tue, 28 Jan 92 14:04:42 GMT
Jeff Dalton writes:
Could someone please explain to me why there needs to be support
for literate comments in the language (rather than in the editor
or some other program) and why conventions involving or
.troff-like-commands are
| Could someone please explain to me why there needs to be support
| for literate comments in the langauge (rather than in the editor
| or some other program) and why conventions involving or
| .troff-like-commands are good ones?
The reason for putting literate comments in the language is so
Original-Via: uk.ac.uknet; Mon, 27 Jan 92 09:49:41 GMT
Yes - please include the literate program convention. I never write any
other way.
Small pedantic point: I think program lines should begin with the two
characters " " to prevent people writing lines beginning "=", which
could confuse the
Original-Via: uk.ac.ed.aiai; Mon, 27 Jan 92 17:36:47 GMT
Could someone please explain to me why there needs to be support
for literate comments in the langauge (rather than in the editor
or some other program) and why conventions involving or
.troff-like-commands are good ones? Maybe I'm just
Original-Via: uk.ac.nsf; Fri, 24 Jan 92 20:04:55 GMT
Haskell 1.2.beta defines (pp. 58 and 89)
class (Num a, Ord a) = Real a
and
class (Real a) = Integral a
Proposal: change this to
class (Num a, Ord a, Enum a) = Real a
and
class (Real a, Ix a) = Integral a
Phil writes:
... (at Glasgow, we use .has for regular and .lhs
for literate).
Make that ".hs" and ".lhs"; ".hs" is standard across all known
implementations; HBC does ".lhs" as well.
Will "We know when Phil last wrote a Haskell pgm :-)" Partain
I'd be happy with a literate style; but time is short, so decision
needed rapidly (Paul) and then (if positive) appropriate changes made
(mainly Joe).
Simon
Original-Via: uk.ac.nsf; Fri, 24 Jan 92 00:07:18 GMT
Original-Sender: [EMAIL PROTECTED]
If I wasn't such a wimp at this point I would have argued as John has;
his argument was exactly why Joe and I made the change. However, the
reality is that I have become a wimp (about syntax, anyway).
Original-Via: uk.ac.nsf; Thu, 23 Jan 92 22:28:37 GMT
So I propose:
the back-quote stuff in the lexical syntax,
and the paren-ifying in the ordinary syntax.
Does anyone else have an opinion. I don't think there are any technical
issues here; just stylistic.
I've been looking at the syntax of LHSes with Brian Boutel.
These are essentially the same for both Haskell 1.1 and 1.2.
As stated in the reports, the syntax is very irregular, allowing
parentheses in some circumstances, but not in others. The result seems
quite arbitrary.
f = ...
Original-Via: uk.ac.nsf; Wed, 22 Jan 92 19:31:00 GMT
I've been receiving the mailing list now for about a year and
now is the first time I've been able to site down and try to code
some stuff in Haskell. Reading the Haskell definition is a bit
tought going, even though I've programmed in
Original-Via: uk.ac.susx.syma; Mon, 20 Jan 92 13:33:58 GMT
How do you force a constructor to be strict in Haskell ?
-- Gavin Wraith
Original-Via: uk.ac.nsf; Sat, 18 Jan 92 14:50:25 GMT
Backquotes with or without whitespace are both fine with me. Paul and I
did in fact discuss this, and when he made his decision, I think it was
a pretty close call.
--Joe
|I see from Joe's revised syntax that he proposes allowing
|
|
So I propose:
the back-quote stuff in the lexical syntax,
and the paren-ifying in the ordinary syntax.
Does anyone else have an opinion. I don't think there are any technical
issues here; just stylistic.
Simon
I agree with you, Simon. Errors from unmatched backquotes
Original-Via: uk.ac.nsf; Fri, 17 Jan 92 18:30:47 GMT
Kudos! And Thanks! What a lovely idea!
(And I wish you good fortune on your royalties.)
Don Stanat
Original-Via: uk.ac.nsf; Thu, 16 Jan 92 20:17:50 GMT
Original-Sender: [EMAIL PROTECTED]
Hmm. That instance declaration is not illegal as things stand. Instance
decls must have the form
instance cxt = C (T u1 ... un) where ...
That is, you can't give an instance decl which gives an
Idea (derived from Lennart's hbc compiler):
allow a class to be exported without its signature
Reason:
module M(f,C)
class C a where
op :: a - a
f :: C a = a - a
f x = op (op x)
We might reasonably want to export "f" but not
Original-Via: uk.ac.nsf; Sat, 11 Jan 92 00:42:09 GMT
Original-Sender: [EMAIL PROTECTED]
I have some problems with modules again. This time with instance
declarations. Consider the following two modules:
module M(C(..),T(..)) where module N(C(..),T(..)) where
import N
Original-Via: uk.ac.st-and.cs; Thu, 9 Jan 92 09:48:48 GMT
Another minor error. On p123, line -5, the syntax of a let expression is
given. The reservedids 'let' and 'in' should be in typwwriter font.
Tony
Original-Via: uk.ac.nsf; Mon, 6 Jan 92 18:54:51 GMT
| On p100 of the report about half way down, the comment preceding the defn
| of (!!) talks about "Array index". Shouldn't this be "List index"? Array
| indexing is elsewhere (!).
|
| On p101 the large comment at the top gives certain rules
Original-Via: uk.ac.st-and.cs; Fri, 3 Jan 92 16:24:54 GMT
On p100 of the report about half way down, the comment preceding the defn
of (!!) talks about "Array index". Shouldn't this be "List index"? Array
indexing is elsewhere (!).
On p101 the large comment at the top gives certain rules obeyed
Original-Via: uk.ac.nsf; Tue, 17 Dec 91 20:24:41 GMT
Original-Sender: [EMAIL PROTECTED]
***
* Haskell B. and LML version 0.997.1 *
* now available from Chalmers *
***
The Haskell B.
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will be made on the Haskell mailing
list. Send mail to haskell-request@{dcs.glasgow.ac.uk,cs.yale.edu} to
subscribe.
Don't get too excited yet: these directories are empty at the moment.
Original-Via: uk.ac.ox.prg; Sun, 15 Dec 91 17:11:26 GMT
***SYNTAX ONLY***
I was quite suprised to see `atype' in the syntax for expression type
signatures in Kevin's proposal:
| exp - exp(0,n) [ :: [ context = ] atype]
Then I looked at the current Haskell report and
Original-Via: uk.ac.nsf; Sun, 15 Dec 91 05:18:50 GMT
What about this (sorry to keep complaining):
module M where
import Prelude hiding (ShowS)
...
Is it legal? Well, that depends what the interface file
for Prelude looks like. If it says (e.g.)
showChar ::
Original-Via: uk.ac.nsf; Sat, 14 Dec 91 08:32:06 GMT
Original-Sender: [EMAIL PROTECTED]
I remember an old suggestion by Kent K, that the Prelude be extended
with something like
infixr @@
f @@ x = f x
to fix the problems of excessive parentheses when programming with
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Original-Via: uk.ac.nsf; Fri, 13 Dec 91 13:53:03 GMT
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I think the problem is that Haskell's eager resolution strategy for
overloading is a major design decision that needs to be emphasized
much more in the preface, but the addition to section 4.5.2 fills the
gap
Original-Via: uk.ac.nsf; Fri, 13 Dec 91 23:01:21 GMT
Original-Sender: [EMAIL PROTECTED]
If class Text is not in PreludeCore any more what is the meaning of the
following program?
-- Lennart
module Foo where
import Prelude hiding(Text(..))
class Text a
data T = A deriving (Text)
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Original-Via: uk.ac.nsf; Sat, 7 Dec 91 13:59:04 GMT
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Original-Via: uk.ac.nsf; Thu, 5 Dec 91 04:33:50 GMT
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| 1. On p. 24, 125 it says
|
| " type -type_1 - type_2
| ...
| Function arrow associate to the right."
|Why not be just as explicit for type expressions as for expressions:
I
Original-Via: uk.ac.nsf; Fri, 29 Nov 91 15:38:59 GMT
Here are some things I would like to see in the next version
of the Report:
(a) A coalesced diagram over the subclass inclusions between all
standard classes (fig. 4, p. 30) and all numeric classes
(fig. 7, p. 55). Below the
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
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
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
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
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
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
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.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 are
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.
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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
directed
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 ---
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