On Thu, Feb 07, 2002 at 08:00:36AM -0800, Ian Zimmerman wrote:

I am new to the language (coming from ML) and I am sorry if my first post turns out to be a flamebait, but I can't help it:

Why in the world did the designers of Haskell permit the ' character to be both a prime (part of identifiers) and the single-character quote? Didn't they realize what they were doing to would-be intelligent editors? Or were they just a bunch of rabid ed users?

In standard ML: - fun f' x = x + 1;

val f' = fn : int -> int

And as far as I see, vim handles that kind of syntax perfectly. I do not find the allowance disturbing, rather neat (I tend to augment helper functions with the '). -- Jesper

On Thu, Feb 07, 2002 at 08:38:22AM -0800, Ian Zimmerman wrote:

You miss my point: I agree that having a prime character for id's is neat. But in SML, that's the _only_ role it has, character literals are written like #"x". With Haskell's characters (and Ocaml's :-( )

Ooops, yup... I forgot the syntax for ML in respect to single characters. I thought it was #'c'. Now I see your point... Still, vim seems to handle it... -- Jesper

Hal> Since we're on this topic, I'm constantly annoyed by the Hal> following (in addition to sexps with '(' and ')'): how to get Hal> emacs to realize that it should match the parens on: Hal> map (\(x,y) -> ... Hal> since \( isn't an escape character. i end up writing: Hal> map (\ (x,y) -> ... Hal> but i'd prefer the former Hal> also, to not thing -- in a string begins a comment: Hal> print "This is not -- I repeat, not -- a comment" Hal> There's one more case, but I'm going blank on it right now. Hal> Anyone have any fixes? Yes, I know about these as well. The first would normally be addressed by (add-hook 'haskell-mode-hook (lambda () (modify-syntax-entry ?\\ "'"))) but of course this screws up parsing of strings, which will now be terminated by \" :-( The second one is because the haskell mode tries to handle comments on its own (and fails), since once again Haskell comments can't be handled by the normal mechanism -- partly because of nested comments, but even the line tail comments are weird due to the single-token rule. All this taken together, I mean, _really_, is the lexical structure of Haskell a botch, or what? -- Ian Zimmerman, Oakland, California, U.S.A. GPG: 433BA087 9C0F 194F 203A 63F7 B1B8 6E5A 8CA3 27DB 433B A087 The world has taken on a thickness of vulgarity that raises a spiritual man's contempt to the violence of a passion. Baudelaire

itz> All this taken together, I mean, _really_, is the lexical itz> structure of Haskell a botch, or what? Jon> No. Innovative. All the problems described in this thread reflect Jon> unwarranted assumptions inherited in emacs. It's plainly possible Jon> to parse Haskell, and not hard either. First, parsing of a complete program (eg. by a compiler) is quite different from parsing a buffer that is being edited by a human. The latter is hard, even for fairly well-specified languages. Irregularities only make it harder. Second, this argument would be easier to accept if there in fact were an equally innovative tool capable of providing all the editing goodies Emacs normally does, for Haskell. But I don't know of one, even now, 10 years or so after Haskell's birth. -- Ian Zimmerman, Oakland, California, U.S.A. GPG: 433BA087 9C0F 194F 203A 63F7 B1B8 6E5A 8CA3 27DB 433B A087 The world has taken on a thickness of vulgarity that raises a spiritual man's contempt to the violence of a passion. Baudelaire

brian> If you think about languages that have been designed to be easy brian> to parse, are these really languages that you would want to brian> use? No, but for different (semantical) reasons. -- Ian Zimmerman, Oakland, California, U.S.A. GPG: 433BA087 9C0F 194F 203A 63F7 B1B8 6E5A 8CA3 27DB 433B A087 The world has taken on a thickness of vulgarity that raises a spiritual man's contempt to the violence of a passion. Baudelaire

On 7 Feb 2002, Ian Zimmerman wrote:

itz> All this taken together, I mean, _really_, is the lexical itz> structure of Haskell a botch, or what?

Jon> No. Innovative. All the problems described in this thread reflect Jon> unwarranted assumptions inherited in emacs. It's plainly possible Jon> to parse Haskell, and not hard either.

First, parsing of a complete program (eg. by a compiler) is quite different from parsing a buffer that is being edited by a human. The latter is hard, even for fairly well-specified languages. Irregularities only make it harder.

Just to show that an opposite point of view is possible: I've recently being thinking about trying to use an ML dialect as part of some interlanguage-prototyping that I'd like to do, since it seems easier to find descriptions of interfacing into it from outside that seem comprehensible to me. I originally learned ML before Haskell, and I imagine that after a little while relearning things aren't lazy and that I shouldn't curry functions unless I need to I'd probably get back into it. But every time I look at it I just get put off by the (IMO) truly awful syntax which is both verbose and seems designed for machine parsing to the detriment of easy human understandability (e.g., ~ for unary minus and the #'c' character literal syntax and those damned end's for terminating let-in constructions). And this is quite important to me because I spend a lot of time reading and thinking about code (particularly paper printouts) and not that much time doing clever emacs searches. I will probably try again to get back into ML, but it will be whilst suppressing feelings of frustration about the syntax.

Second, this argument would be easier to accept if there in fact were an equally innovative tool capable of providing all the editing goodies Emacs normally does, for Haskell. But I don't know of one, even now, 10 years or so after Haskell's birth.

That may be more indicative of the fact that few people in the community find writing editing modes to be interesting things to do, and that emacs is still using parsing tricks that made sense when people were editing on slow, time-shared machines but not when the typical desktop machine is at least a 200MHz pentium. There was recently a PhD position advertised on the list in the area of refactoring functional programs; I'd be surprised if whoever does that doesn't eventually end up with a GUI (whether inherited from somewhere else or written as part of the project). ___cheers,_dave_________________________________________________________ www.cs.bris.ac.uk/~tweed/|`...heat generated by its microprocessors will email:tweed@cs.bris.ac.uk|slope upward exponentially, reaching the power work tel:(0117) 954-5250 |density of a nuclear reactor before 2010'-Intel

Personally, I think the Haskell syntax is beautiful. Programs are readable, yet concise. That's more important to me than correct parenthesis matching. Haskell looks nice... Isabell looks beautiful :-) (in Xemacs with the X symbol package+Proof General etc) I whish I could have lambdas, alphas and all that .

(BTW, I'm a happy Emacs user -- e.g. see my headers -- and I find the modes available pretty much sufficient.) I'm not... like I said working with Isabell is great. Haskell mode is pretty basic when compared to it. And no, I don't have the time to do something better myself now, so I'll just stick to it :-)

J.A.

On Friday 08 February 2002 14:35, Ketil Z. Malde wrote:

Jorge Adriano writes:

...

Haskell looks nice... Isabell looks beautiful :-)

I'm not familiar with Isabell, but aren't we comparing apples and oranges here? E.g. you can prettify .lhs pretty nicely with one of the LaTeX packages available.

Well yes :-) You said "Personally, I think the Haskell syntax is beautiful", and in my answer I talked about the way it looked on Xemacs, not the syntax. But not sure if we are talking about the same thing here, how do you prettify the .lhs files? Are you talking about the dvi you get in the end or the way it looks while editing the code?

...

And no, I don't have the time to do something better myself now, so I'll just stick to it :-)

If somebody would come up with a mode that used lambdas and arrows to render things nicely in my editor, I wouldn't mind. But I don't think the benefit for me would be great enough to justify the effort (I'm not much of a lisp hacker).

I wouldn't mind either. Everything looks really nice, making your code really easy to read, it's not just the greek leters, the 'forall's, the arrows '=>', the 'and's and the 'or's. But the Isabell/Isar/Proof General (which I haven't used in a long time) mode had more to it than just that. The menus were pretty good, buttons (with icons) for some commands... it turns Xemacs into a very nice GUI for isabelle. J.A.