Re: [Haskell-cafe] Monoid wants a (++) equivalent

Mattias Bengtsson writes: >> (?) is also undefined in Prelude. > Which i think is a good thing. > I think it's quite nice to use (?) as an operator in higher order > functions. Also, it clashes with the implicit parameters extension, and combining the extension with a user-defined (?) operato

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Sun, 2009-07-05 at 22:30 +0200, Henning Thielemann wrote: > > (?) is also undefined in Prelude. Which i think is a good thing. I think it's quite nice to use (?) as an operator in higher order functions. Eg. foldr _ z [] = z foldr (?) z (x:xs) = x ? foldr (?) z xs ___

Re: [Haskell-cafe] Monoid wants a (++) equivalent

While I like the idea of (++) as mappend to some extent, two objections immediately come to mind: 1.) While I like the appeal to the PVP to export a version of (++) from Data.Monoid and I think this has worked out well for new modules like Control.Category, I'm not sure that with a module that has

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, 30 Jun 2009, Bryan O'Sullivan wrote: I've thought for a while that it would be very nice indeed if the Monoid class had a more concise operator for infix appending than "a `mappend` b". I wonder if other people are of a similar opinion, and if so, whether this is worth submitting a li

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Robert Greayer schrieb: > I'm sure there's some important historical reason... but why isn't '&' > used in something more prominent than the fgl package? I understand > why it's not used for bitwise AND in Data.Bits (I assume because the > corresponding bitwise '|' operator isn't available), but a

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Jul 4, 2009, at 01:17 , Jason Dusek wrote: What is the proper name for the operation on functions of a functor, anyway? The name `fmap` seems to driven by an analogy with `map`. (.) -- brandon s. allbery [solaris,freebsd,perl,pugs,haskell] allb...@kf8nh.com system administrator [opena

Re: [Haskell-cafe] Monoid wants a (++) equivalent

2009/7/4 Jason Dusek : > 2009/07/03 George Pollard : >> Also, throw out `map`. ;) > >  What is the proper name for the operation on functions of a >  functor, anyway? The name `fmap` seems to driven by an analogy >  with `map`. This is getting a little off topic, but I don't believe it has a name.

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Fri, Jul 3, 2009 at 10:17 PM, Jason Dusek wrote: > 2009/07/03 George Pollard : >> This discussion points to a wider issue: at some stage we >> should look at pulling all the nice "new" stuff into Haskell >> prelude. I'm looking at you, Data.Foldable,Traversable. >> >> Also, throw out `map`. ;) >

Re: [Haskell-cafe] Monoid wants a (++) equivalent

2009/07/03 George Pollard : > This discussion points to a wider issue: at some stage we > should look at pulling all the nice "new" stuff into Haskell > prelude. I'm looking at you, Data.Foldable,Traversable. > > Also, throw out `map`. ;) What is the proper name for the operation on functions of

Re: [Haskell-cafe] Monoid wants a (++) equivalent

This discussion points to a wider issue: at some stage we should look at pulling all the nice "new" stuff into Haskell prelude. I'm looking at you, Data.Foldable,Traversable. Also, throw out `map`. ;) ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.or

Re: [Haskell-cafe] Monoid wants a (++) equivalent

It is claimed that making ++ become another name for the Monoid mappend operation "will break some Haskell 98 code" such as append = (++) That example can easily be fixed by adding a type signature, no? append :: [a] -> [a] -> [a] append = (++) In ghci, at any rate, usi

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Wed, Jul 1, 2009 at 4:17 PM, Raynor Vliegendhart wrote: > We could use (Control.Category..) as an operator, but this would > require an additional wrapping layer if we wish to use the existing > Monoid instances: > > > import Prelude hiding (id, (.)) > > import Control.Category > > import Data.Mo

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Thu, Jul 02, 2009 at 12:46:37PM +0100, Jules Bean wrote: > I'm not the person who would have to maintain that arrangement. I guess > that's a call for the people who would have to do the work. There is > already a haskell98 package, I think, which is the first step? The Prelude is in the ba

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 10:11 PM, David Menendez wrote: > In Wed, Jul 1, 2009 at 3:38 PM, Thomas Schilling > wrote: >> 2009/7/1 David Leimbach >>> Just because the compiler can figure out what I mean because it has a great >>> type system, I might not be able to figure out what I mean a year from

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 11:26 AM, Ross Paterson wrote: > On Wed, Jul 01, 2009 at 10:55:39AM -0700, Bryan O'Sullivan wrote: >> Okay, here's a tentative plan that will help to figure out the answer. I'll >> build a fiddled base package that rewires the Monoid class to have (++) be >> the >> binary op

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Ross Paterson wrote: On Wed, Jul 01, 2009 at 10:55:39AM -0700, Bryan O'Sullivan wrote: Okay, here's a tentative plan that will help to figure out the answer. I'll build a fiddled base package that rewires the Monoid class to have (++) be the binary operator, and mappend as a synonym for it. I'll

Re: [Haskell-cafe] Monoid wants a (++) equivalent

In Wed, Jul 1, 2009 at 3:38 PM, Thomas Schilling wrote: > 2009/7/1 David Leimbach >> Just because the compiler can figure out what I mean because it has a great >> type system, I might not be able to figure out what I mean a year from now >> if I see ++ everywhere. > Yep, had the same experience.

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Obviously `mappend` is good enough as it is. Choosing (+>) or (<>) are just for prettifying code. Generalizing (++) not only makes the code prettier, but also brings Monoid into the Prelude. You can either Do It Right(tm), or be conservative and try to maintain backwards compatibility as much as

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 6:45 PM, Bryan O'Sullivan wrote: > I've thought for a while that it would be very nice indeed if the Monoid > class had a more concise operator for infix appending than "a `mappend` b". > I wonder if other people are of a similar opinion, and if so, whether this > is worth s

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Thomas Schilling wrote: Haddock should allow documentation on instance declarations... +1! ___ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe

Re: [Haskell-cafe] Monoid wants a (++) equivalent

2009/7/1 David Leimbach > I like this thinking as well.  I kind of wish Haskell didn't overload > operators to begin with but oh well :-) > Just because the compiler can figure out what I mean because it has a great > type system, I might not be able to figure out what I mean a year from now > if

Re: [Haskell-cafe] Monoid wants a (++) equivalent

2009/7/1 Ross Paterson : >>> I'm rather fond of the (<>) suggestion, but would be happy with >>> anything better than mappend! ;) >> >> I find it rather ugly, it has a lot of connotations of "does not equals" >> from other languages. > > Forget Pascal: think of it as a diamond. Yep, it's definitel

Re: [Haskell-cafe] Monoid wants a (++) equivalent

2009/7/1 Martijn van Steenbergen : > I suggest you all add your name and vote here: > >   http://doodle.com/4yrfd7qaw5man3rm > > Perhaps we'll find one of the options is clearly in favor. Doesn't doodle allow multiple choice tests? Requiring to pick only one is kind of skewing the results towards

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Ross Paterson wrote: Generalizing (++) will break some Haskell 98 code, e.g. append = (++) I think that's a show-stopper. Is the monomorphism restriction the only situation in which stuff breaks? Martijn. ___ Haskell-Cafe mailing list Haskell-Caf

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 01, 2009 at 10:55:39AM -0700, Bryan O'Sullivan wrote: > Okay, here's a tentative plan that will help to figure out the answer. I'll > build a fiddled base package that rewires the Monoid class to have (++) be the > binary operator, and mappend as a synonym for it. I'll import the Monoid

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 10:55 AM, Bryan O'Sullivan wrote: > On Wed, Jul 1, 2009 at 3:38 AM, Duncan Coutts > wrote: > >> >> I agree, if we can't use ++ then <> is the next best thing. > > > Okay, here's a tentative plan that will help to figure out the answer. I'll > build a fiddled base package th

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 3:38 AM, Duncan Coutts wrote: > > I agree, if we can't use ++ then <> is the next best thing. Okay, here's a tentative plan that will help to figure out the answer. I'll build a fiddled base package that rewires the Monoid class to have (++) be the binary operator, and map

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 5:18 AM, Jules Bean wrote: > Duncan Coutts wrote: > >> I agree, if we can't use ++ then <> is the next best thing. As John says >> it's already a monoid operator for Data.Sequence and Text.PrettyPrint. >> >> > I agree, if we can't use +> and <+ then <> is the next best thin

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 01, 2009 at 04:53:05PM +0200, Thomas Davie wrote: > > On 1 Jul 2009, at 16:46, Edward Kmett wrote: > >> I'm rather fond of the (<>) suggestion, but would be happy with >> anything better than mappend! ;) > > I find it rather ugly, it has a lot of connotations of "does not equals" > f

Re: [Haskell-cafe] Monoid wants a (++) equivalent

I'm sure there's some important historical reason... but why isn't '&' used in something more prominent than the fgl package? I understand why it's not used for bitwise AND in Data.Bits (I assume because the corresponding bitwise '|' operator isn't available), but all the other single-character op

Re: [Haskell-cafe] Monoid wants a (++) equivalent

I suggest you all add your name and vote here: http://doodle.com/4yrfd7qaw5man3rm Perhaps we'll find one of the options is clearly in favor. Martijn. Bryan O'Sullivan wrote: I've thought for a while that it would be very nice indeed if the Monoid class had a more concise operator for infi

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 7:53 AM, Thomas Davie wrote: > > On 1 Jul 2009, at 16:46, Edward Kmett wrote: > > I'm rather fond of the (<>) suggestion, but would be happy with anything >> better than mappend! ;) >> > > I find it rather ugly, it has a lot of connotations of "does not equals" > from othe

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On 1 Jul 2009, at 16:46, Edward Kmett wrote: I'm rather fond of the (<>) suggestion, but would be happy with anything better than mappend! ;) I find it rather ugly, it has a lot of connotations of "does not equals" from other languages. Personally I'm in favor of <+>, simply because it

Re: [Haskell-cafe] Monoid wants a (++) equivalent

I'm rather fond of the (<>) suggestion, but would be happy with anything better than mappend! ;) -Ed On Wed, Jul 1, 2009 at 8:56 AM, Brent Yorgey wrote: > On Wed, Jul 01, 2009 at 12:00:50AM -0400, a...@spamcop.net wrote: > > G'day all. > > > > On Tue, Jun 30, 2009 at 08:02:48PM -0400, Daniel P

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 01, 2009 at 12:00:50AM -0400, a...@spamcop.net wrote: > G'day all. > > On Tue, Jun 30, 2009 at 08:02:48PM -0400, Daniel Peebles wrote: > >> But we don't want to imply it's commutative either. Having something >> "bidirectional" like <> or <+> feels more commutative than associative >> t

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 2:18 PM, Jules Bean wrote: > Duncan Coutts wrote: >> I agree, if we can't use ++ then <> is the next best thing. As John says >> it's already a monoid operator for Data.Sequence and Text.PrettyPrint. > I agree, if we can't use +> and <+ then <> is the next best thing. > ;

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Duncan Coutts wrote: I agree, if we can't use ++ then <> is the next best thing. As John says it's already a monoid operator for Data.Sequence and Text.PrettyPrint. I agree, if we can't use +> and <+ then <> is the next best thing. ;) Jules ___ Has

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, 2009-06-30 at 18:31 -0700, John Meacham wrote: > On Tue, Jun 30, 2009 at 08:02:48PM -0400, Daniel Peebles wrote: > > But we don't want to imply it's commutative either. Having something > > "bidirectional" like <> or <+> feels more commutative than associative > > to me. Of course in Text.

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Wed, Jul 1, 2009 at 9:34 AM, Jochem Berndsen wrote: > a...@spamcop.net wrote: >> I tend to agree.  Moreover, and I realise this may be a losing battle, >> I want (++) to be the generic operator. > I totally agree. So do I. David. ___ Haskell-Cafe m

Re: [Haskell-cafe] Monoid wants a (++) equivalent

a...@spamcop.net wrote: > G'day all. > > Quoting John Meacham : > >> (+>) seems to imply to me that the operator is non-associative. Something >> like (<>) or (<+>) would be better. > > I tend to agree. Moreover, and I realise this may be a losing battle, > I want (++) to be the generic operato

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 11:24 PM, Ketil Malde wrote: > > You know, this might be the right time to start expanding our > vocabulary beyond seven bits.  Since we're likely to keep mappend > around as an alias for some time, people would have a grace period to > adjust. > > How about U+2295 (circle w

Re: [Haskell-cafe] Monoid wants a (++) equivalent

You know, this might be the right time to start expanding our vocabulary beyond seven bits. Since we're likely to keep mappend around as an alias for some time, people would have a grace period to adjust. How about U+2295 (circle with plus inside it)? Or, if we would like to stick to the 8-bit

Re: [Haskell-cafe] Monoid wants a (++) equivalent

G'day all. On Tue, Jun 30, 2009 at 08:02:48PM -0400, Daniel Peebles wrote: But we don't want to imply it's commutative either. Having something "bidirectional" like <> or <+> feels more commutative than associative to me. Quoting John Meacham : Not really, think of '++', which doesn't commu

Re: [Haskell-cafe] Monoid wants a (++) equivalent

G'day all. Quoting John Meacham : (+>) seems to imply to me that the operator is non-associative. Something like (<>) or (<+>) would be better. I tend to agree. Moreover, and I realise this may be a losing battle, I want (++) to be the generic operator. I understand the argument. I even ag

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Ok. When nobody can agree on a graphical operator can it be shortened to "mop" and "munit"? (Personally I'm for (++). (Yeah, I know.)) -ljr Daniel Peebles wrote: > But we don't want to imply it's commutative either. Having something > "bidirectional" like <> or <+> feels more commutative tha

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 08:02:48PM -0400, Daniel Peebles wrote: > But we don't want to imply it's commutative either. Having something > "bidirectional" like <> or <+> feels more commutative than associative > to me. Not really, think of '++', which doesn't commute but is visually symmetric, or Da

Re: [Haskell-cafe] Monoid wants a (++) equivalent

But we don't want to imply it's commutative either. Having something "bidirectional" like <> or <+> feels more commutative than associative to me. On Tue, Jun 30, 2009 at 6:39 PM, John Meacham wrote: > On Tue, Jun 30, 2009 at 02:54:38PM -0400, Brent Yorgey wrote: >> On Tue, Jun 30, 2009 at 09:45:4

Re: [Haskell-cafe] Monoid wants a (++) equivalent

David Leimbach wrote: > > > On Tue, Jun 30, 2009 at 11:54 AM, Brent Yorgey > wrote: > > On Tue, Jun 30, 2009 at 09:45:45AM -0700, Bryan O'Sullivan wrote: > > I've thought for a while that it would be very nice indeed if > the Monoid > > class had a

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 3:56 PM, Ross Paterson wrote: > On Tue, Jun 30, 2009 at 03:39:39PM -0700, John Meacham wrote: > > (+>) seems to imply to me that the operator is non-associative. > > It does seem to imply some asymmetry between the arguments. > Well, the canonical instance of Monoid is to

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 03:39:39PM -0700, John Meacham wrote: > (+>) seems to imply to me that the operator is non-associative. It does seem to imply some asymmetry between the arguments. > Something like (<>) or (<+>) would be better. (<+>) is used in Control.Arrow. (<>) is used in Data.Sequen

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 3:50 PM, Dougal Stanton wrote: > > (+>) seems to imply to me that the operator is non-associative. Something > > like (<>) or (<+>) would be better. > > It's too similar to the applicative (*>), and implies all sorts of > things like different types of the two arguments an

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 11:39 PM, John Meacham wrote: > > (+>) seems to imply to me that the operator is non-associative. Something > like (<>) or (<+>) would be better. > It's too similar to the applicative (*>), and implies all sorts of things like different types of the two arguments and so on

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 02:54:38PM -0400, Brent Yorgey wrote: > On Tue, Jun 30, 2009 at 09:45:45AM -0700, Bryan O'Sullivan wrote: > > I've thought for a while that it would be very nice indeed if the Monoid > > class had a more concise operator for infix appending than "a `mappend` b". > > I wonder

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 1:33 PM, Thomas Davie wrote: > I excellently think your proposal is a correct assessment. > Well then, here's the library enhancement ticket: http://hackage.haskell.org/trac/ghc/ticket/3339 ___ Haskell-Cafe mailing list Haskell

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On 30 Jun 2009, at 22:19, Daniel Fischer wrote: Am Dienstag 30 Juni 2009 20:56:10 schrieb David Leimbach: On Tue, Jun 30, 2009 at 11:54 AM, Brent Yorgey >wrote: On Tue, Jun 30, 2009 at 09:45:45AM -0700, Bryan O'Sullivan wrote: I've thought for a while that it would be very nice indeed if the

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Am Dienstag 30 Juni 2009 20:56:10 schrieb David Leimbach: > On Tue, Jun 30, 2009 at 11:54 AM, Brent Yorgey wrote: > > On Tue, Jun 30, 2009 at 09:45:45AM -0700, Bryan O'Sullivan wrote: > > > I've thought for a while that it would be very nice indeed if the > > > Monoid class had a more concise opera

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 11:54 AM, Brent Yorgey wrote: > On Tue, Jun 30, 2009 at 09:45:45AM -0700, Bryan O'Sullivan wrote: > > I've thought for a while that it would be very nice indeed if the Monoid > > class had a more concise operator for infix appending than "a `mappend` > b". > > I wonder if o

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 09:45:45AM -0700, Bryan O'Sullivan wrote: > I've thought for a while that it would be very nice indeed if the Monoid > class had a more concise operator for infix appending than "a `mappend` b". > I wonder if other people are of a similar opinion, and if so, whether this > i

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Except that in this case the operator is associative :P On Tue, Jun 30, 2009 at 2:42 PM, David Leimbach wrote: > > > On Tue, Jun 30, 2009 at 10:04 AM, Bryan O'Sullivan > wrote: >> >> On Tue, Jun 30, 2009 at 9:50 AM, David Leimbach wrote: >>> >>> I actually worry that this will make people think,

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 10:04 AM, Bryan O'Sullivan wrote: > On Tue, Jun 30, 2009 at 9:50 AM, David Leimbach wrote: > >> I actually worry that this will make people think, more incorrectly, that >> Monoids are about appending stuff only. >> > > I think that adding a graphical operator as a synonym

Re: [Haskell-cafe] Monoid wants a (++) equivalent

Isn't "++" itself the perfect Monoid operator? Lambdabot seems to think so. On Tue, Jun 30, 2009 at 13:04, Edward Kmett wrote: > I love the idea, but its tricky to come up with one that is good that won't > break a lot of user code that imports Data.Monoid unqualified. > -Edward Kmett > > On Tue,

Re: [Haskell-cafe] Monoid wants a (++) equivalent

I love the idea, but its tricky to come up with one that is good that won't break a lot of user code that imports Data.Monoid unqualified. -Edward Kmett On Tue, Jun 30, 2009 at 12:45 PM, Bryan O'Sullivan wrote: > I've thought for a while that it would be very nice indeed if the Monoid > class ha

Re: [Haskell-cafe] Monoid wants a (++) equivalent

On Tue, Jun 30, 2009 at 9:50 AM, David Leimbach wrote: > I actually worry that this will make people think, more incorrectly, that > Monoids are about appending stuff only. > I think that adding a graphical operator as a synonym for mappend would actually help to address that, since the magic wo

[Haskell-cafe] Monoid wants a (++) equivalent

I've thought for a while that it would be very nice indeed if the Monoid class had a more concise operator for infix appending than "a `mappend` b". I wonder if other people are of a similar opinion, and if so, whether this is worth submitting a libraries@ proposal over. ___