q-lang-users — general discussion, questions, suggestions, etc.

Re: [q-lang-users] Pure

[Libor S. <li...@gm...>]

Eddie,

Sorry, I must be dyslexic too, I meant 8.04., 64bit.
It took a dislike to my ATA disks, though previous Ubuntus were OK with them.
However, I found some "magic incantation" boot options and it works now.
You were lucky to get an easy ride, I think. 
I will look for the LLVM software sources, 
I like them for their automatic updates.

Libor

On Mon, 28 Apr 2008 14:14:04 +0100, Eddie Rucker <er...@bm...> wrote:

> On Mon, 2008-04-28 at 11:45 +0100, Libor Spacek wrote:
>
>> I have installed Ubuntu 4.08, which was, unexpectedly, a pain in the neck.
>
> This is off topic but, why such an old version? I'm using 8.04 (I'm
> dyslexic so I didn't catch that at first) and it was fairly painless to
> install. You can get LLVM 2.3 through the Synaptic Package Manager by
> adding more software sources but I don't know what they are. Sometimes I
> prefer the manual install ;) I installed Ubuntu, then Ubuntu 64bit, then
> back to Ubunto. Although not Linux, I think I liked FreeBSD of all the
> OSs I've used and that is quite a list.

Re: [q-lang-users] Pure

[Eddie R. <er...@bm...>]

On Mon, 2008-04-28 at 11:45 +0100, Libor Spacek wrote:

> I have installed Ubuntu 4.08, which was, unexpectedly, a pain in the neck.

This is off topic but, why such an old version? I'm using 8.04 (I'm
dyslexic so I didn't catch that at first) and it was fairly painless to
install. You can get LLVM 2.3 through the Synaptic Package Manager by
adding more software sources but I don't know what they are. Sometimes I
prefer the manual install ;) I installed Ubuntu, then Ubuntu 64bit, then
back to Ubunto. Although not Linux, I think I liked FreeBSD of all the
OSs I've used and that is quite a list.

> > Hi friends,


> > BTW, the present version is some 30-40 times faster than Q on naive fib,
> > IIRC. I was hoping for more, but it's already 7 times faster than Python
> > 2.4 on the recursive benchmark from the shootout, and it certainly makes

I wonder if Python 2.5 is faster than 2.4? MzScheme seemed to be faster
than Python 2.5 on most of the bench marks on the shootout. Lua seems
pretty fast too. The OCaml interpreter absolutely smokes. If I were
aiming for speed, the OCaml interpreter is the one to chase. However,
IIRC, BigIntegers are not built into OCaml and that and type information
can have a major impact on speed.

Eddie

Re: [q-lang-users] Pure

[Libor S. <li...@gm...>]

Albert,

Looking at the LLVM website again, I note their latest SVN version (LLVM 2.3) features
llvm-gcc 4.2 and significant code generator and optimiser improvements.

Would it be worth shooting for this latest version, or is it likely to break Pure?
Would you care to test it and see if it (a) works, (b) runs faster?

Libor

Re: [q-lang-users] Pure

[Libor S. <li...@gm...>]

Albert,

It is great to hear about your progress!

I suspect the answer to beating even more languages lies in making your 
matcher as fast as possible, so that it can approach the speed of a fixed
function call that most other languages use.

You probably know a lot more about this but if I was implementing Pure I would
start by converting all operators/functors/constructors to the same internal
representation, such as *(X,Y) instead of X*Y and then have a very efficient
indexing scheme (hashing?) for locating the LHS of the next equation to invoke. 
In this example, I know I only need to look for functor "*" with two arguments.

I have installed Ubuntu 4.08, which was, unexpectedly, a pain in the neck.
It comes with an old version of LLVM available and that installed easily.
Next I will have a go at a manual installation of LLVM 2.2.

Regards, Libor

On Sun, 27 Apr 2008 04:22:22 +0100, Albert Graef <Dr....@t-...> wrote:

> Hi friends,
>
> well, it was quite a bit more work than I expected, but it finally
> works! :) And I already have the Pure->C interface, exceptions
> (catch/throw) and a considerable part of the system module working
> (basic I/O, printf/scanf, glob, regex). Nicely enough, I can write most
> of the wrappers in Pure now.
>
> BTW, the present version is some 30-40 times faster than Q on naive fib,
> IIRC. I was hoping for more, but it's already 7 times faster than Python
> 2.4 on the recursive benchmark from the shootout, and it certainly makes
> Hugs look very bad; MZ Scheme is still a bit faster, though. So I guess
> it's fast enough -- and there's no doubt that the generated code can
> still be improved. ;-)
>
> Still working on a few examples, too tired to do a prerelease tonight.
> Maybe tomorrow. For the time being, get LLVM 2.2 up and running on your
> machines, you'll need it. ;-)
>
> Cheers,
> Albert

Re: [q-lang-users] Pure

[Albert G. <Dr....@t-...>]

Hi friends,

well, it was quite a bit more work than I expected, but it finally
works! :) And I already have the Pure->C interface, exceptions
(catch/throw) and a considerable part of the system module working
(basic I/O, printf/scanf, glob, regex). Nicely enough, I can write most
of the wrappers in Pure now.

BTW, the present version is some 30-40 times faster than Q on naive fib,
IIRC. I was hoping for more, but it's already 7 times faster than Python
2.4 on the recursive benchmark from the shootout, and it certainly makes
Hugs look very bad; MZ Scheme is still a bit faster, though. So I guess
it's fast enough -- and there's no doubt that the generated code can
still be improved. ;-)

Still working on a few examples, too tired to do a prerelease tonight.
Maybe tomorrow. For the time being, get LLVM 2.2 up and running on your
machines, you'll need it. ;-)

Cheers,
Albert

Eddie Rucker wrote:
> Yea, how is everything Albert? 
> 
> I've got one more killer week and then I'm going to get to work on the
> wrapping GSL. I'll be so glad to have some play time with Q.
> 
> Eddie
> 
> On Fri, 2008-04-25 at 21:45 +0100, Libor Spacek wrote:
>> Albert,
>>
>> How are you getting on with LLVM and Pure?
>> You went suddenly quiet about it but some of us are still here,
>> looking forward to an early release of Pure.
>>
>> Libor

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag

Re: [q-lang-users] Pure

[Eddie R. <er...@bm...>]

Yea, how is everything Albert? 

I've got one more killer week and then I'm going to get to work on the
wrapping GSL. I'll be so glad to have some play time with Q.

Eddie

On Fri, 2008-04-25 at 21:45 +0100, Libor Spacek wrote:
> Albert,
> 
> How are you getting on with LLVM and Pure?
> You went suddenly quiet about it but some of us are still here,
> looking forward to an early release of Pure.
> 
> Libor
> 
> 
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Re: [q-lang-users] Pure

[Libor S. <li...@gm...>]

Albert,

How are you getting on with LLVM and Pure?
You went suddenly quiet about it but some of us are still here,
looking forward to an early release of Pure.

Libor

Re: [q-lang-users] Q 7.11 on Mac OS X

[Don G. <dg...@cc...>]

Ah, thanks.
--
don


On Apr 18, 2008, at 9:37 PM, Ryan Schmidt wrote:

> The portindex only regenerates every 12 hours, so wait a little  
> longer.
>
>
> On Apr 18, 2008, at 10:08 PM, Don Groves wrote:
>
>> I just did selfupdate on MacPorts and list still shows version 7.10.
>> Anything else I need to do to get 7.11?
>>
>>
>> On Apr 18, 2008, at 6:37 PM, Ryan Schmidt wrote:
>>
>>> On Mar 11, 2008, at 3:46 AM, Albert Graef wrote:
>>>> Ryan Schmidt wrote:
>>>>> Hello. Q 7.10 compiled just fine on Mac OS X 10.4.11 Intel, but
>>>>> 7.11
>>>>> doesn't. Here's what it does:
>>>>
>>>> Hmm, any news on that? Didn't the patch I posted work for you?
>>>
>>> Sorry for the delay. The patch worked fine, Q 7.11 now compiles, and
>>> I've updated the port in MacPorts.
>
> -------------------------------------------------------------------------
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Re: [q-lang-users] Q 7.11 on Mac OS X

[Ryan S. <rya...@us...>]

The portindex only regenerates every 12 hours, so wait a little longer.


On Apr 18, 2008, at 10:08 PM, Don Groves wrote:

> I just did selfupdate on MacPorts and list still shows version 7.10.
> Anything else I need to do to get 7.11?
>
>
> On Apr 18, 2008, at 6:37 PM, Ryan Schmidt wrote:
>
>> On Mar 11, 2008, at 3:46 AM, Albert Graef wrote:
>>> Ryan Schmidt wrote:
>>>> Hello. Q 7.10 compiled just fine on Mac OS X 10.4.11 Intel, but  
>>>> 7.11
>>>> doesn't. Here's what it does:
>>>
>>> Hmm, any news on that? Didn't the patch I posted work for you?
>>
>> Sorry for the delay. The patch worked fine, Q 7.11 now compiles, and
>> I've updated the port in MacPorts.

Re: [q-lang-users] Q 7.11 on Mac OS X

[Don G. <dg...@cc...>]

I just did selfupdate on MacPorts and list still shows version 7.10.
Anything else I need to do to get 7.11?
--
don


On Apr 18, 2008, at 6:37 PM, Ryan Schmidt wrote:

> On Mar 11, 2008, at 3:46 AM, Albert Graef wrote:
>> Ryan Schmidt wrote:
>>> Hello. Q 7.10 compiled just fine on Mac OS X 10.4.11 Intel, but 7.11
>>> doesn't. Here's what it does:
>>
>> Hmm, any news on that? Didn't the patch I posted work for you?
>
> Sorry for the delay. The patch worked fine, Q 7.11 now compiles, and
> I've updated the port in MacPorts.
>
>
>
> -------------------------------------------------------------------------
> This SF.net email is sponsored by the 2008 JavaOne(SM) Conference
> Don't miss this year's exciting event. There's still time to save  
> $100.
> Use priority code J8TL2D2.
> http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone
> _______________________________________________
> q-lang-users mailing list
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> https://lists.sourceforge.net/lists/listinfo/q-lang-users
>

Re: [q-lang-users] Q 7.11 on Mac OS X

[Ryan S. <rya...@us...>]

On Mar 11, 2008, at 3:46 AM, Albert Graef wrote:
> Ryan Schmidt wrote:
>> Hello. Q 7.10 compiled just fine on Mac OS X 10.4.11 Intel, but 7.11
>> doesn't. Here's what it does:
>
> Hmm, any news on that? Didn't the patch I posted work for you?

Sorry for the delay. The patch worked fine, Q 7.11 now compiles, and  
I've updated the port in MacPorts.

Re: [q-lang-users] Problems installing on OS X

[Ryan S. <rya...@us...>]

On Apr 7, 2008, at 05:21, Tim Haynes wrote:

[q in macports]

> Needs more variants adding for things like ODBC, I think...

I'm happy to add variants to the port. I don't use q myself so I  
don't really know what's typical or desired. But if you will file  
enhancement requests in the issue tracker and assign (or Cc) them to  
me, ideally including a patch to the portfile to implement it, or at  
least mentioning which configure flag is necessary, I'll try to add it.

http://guide.macports.org/#project

Re: [q-lang-users] Problems installing on OS X

[Tim H. <q...@st...>]

Don Groves <dg...@cc...> writes:

> Hi, all --
>
> I'm highly interested in Q and just tried to install the MacPorts  
> version with the following results:
>
>   --->  Fetching pkgconfig
> ...
> --->  Activating zlib 1.2.3_1
> Error: Target org.macports.activate returned: Image error: /opt/local/ 
> include/zconf.h already exists and does not belong to a registered  
> port.  Unable to activate port zlib.
> Error: The following dependencies failed to build: curl zlib gmp  
> readline ncurses ncursesw
> Error: Status 1 encountered during processing.
>
> Any help will be greatly appreciated.


Where did you get your /opt/local/include/zconf.h from, if not ports? 

Either remove the offending files, run 
       port clean zlib && port install zlib

, or you can forcibly activate it with 
    port -f activate zlib
and resume, see what that does.

I just grabbed and built the latest MacPorts (on a PPC box) over this past
weekend and had no such problem. So finally...

 | zsh, pizza 11:08AM ~/ # port install q
 | --->  Fetching q
 | --->  Attempting to fetch q-7.10.tar.gz from
 | http://downloads.sourceforge.net/q-lang
 | --->  Verifying checksum(s) for q
 | --->  Extracting q
 | --->  Configuring q
 | --->  Building q with target all
 | --->  Staging q into destroot
 | --->  Installing q 7.10_0
 | --->  Activating q 7.10_0
 | --->  Cleaning q
 | zsh, pizza 11:16AM ~/ # 

It works! 

Needs more variants adding for things like ODBC, I think...

~Tim
-- 
<http://spodzone.org.uk/>

Re: [q-lang-users] Problems installing on OS X

[Don G. <dg...@cc...>]

On Apr 6, 2008, at 19:18 , Ryan Schmidt wrote:
>
> On Apr 6, 2008, at 17:16, Ryan Schmidt wrote:
>
>> You can also force the activation of the zlib port. For each file
>> it's trying to install which it finds to already exist, it will
>> rename it, tell you about it, then install the file it was going to
>> install. You can manually remove the renamed older files later.
>
> Sorry, I forgot to say how to do this. To force the activation if the
> zlib port if you get that error message, you can:
>
> sudo port -f activate zlib

Thanks, Ryan, this solved the problem for me. Now that I know a
bit about MacPorts, I'll ask in the right venue next time.
--
don

Re: [q-lang-users] Problems installing on OS X

[Ryan S. <rya...@us...>]

On Apr 6, 2008, at 17:16, Ryan Schmidt wrote:

> You can also force the activation of the zlib port. For each file
> it's trying to install which it finds to already exist, it will
> rename it, tell you about it, then install the file it was going to
> install. You can manually remove the renamed older files later.

Sorry, I forgot to say how to do this. To force the activation if the  
zlib port if you get that error message, you can:

sudo port -f activate zlib

Re: [q-lang-users] Problems installing on OS X

[Ryan S. <rya...@us...>]

On Apr 5, 2008, at 21:44, Don Groves wrote:

> I'm highly interested in Q and just tried to install the MacPorts
> version with the following results:
>
>   --->  Fetching pkgconfig
> ...
> --->  Activating zlib 1.2.3_1
> Error: Target org.macports.activate returned: Image error: /opt/local/
> include/zconf.h already exists and does not belong to a registered
> port.  Unable to activate port zlib.
> Error: The following dependencies failed to build: curl zlib gmp
> readline ncurses ncursesw
> Error: Status 1 encountered during processing.
>
> Any help will be greatly appreciated.

This question really belongs on the macports-users mailing list, not  
the q-lang-users list, since your problem right now is with  
installing zlib, not q.

The message means that the zlib port is trying to install the file / 
opt/local/include/zconf.h but this file already exists on your  
system. Why does it? It shouldn't, unless you had a previous  
installation of MacPorts, removed it incompletely, and then  
reinstalled it. If that's the case, you should remove MacPorts  
completely [1] and reinstall it and then everything should work.

You can also force the activation of the zlib port. For each file  
it's trying to install which it finds to already exist, it will  
rename it, tell you about it, then install the file it was going to  
install. You can manually remove the renamed older files later. You  
should not generally need to go through all this, though. If you find  
this happening on many ports, something is amiss in your MacPorts  
installation, and the best idea is to remove and reinstall.

[1] http://trac.macports.org/projects/macports/wiki/ 
FAQ#HowdoIremoveoruninstallMacPorts

[q-lang-users] Problems installing on OS X

[Don G. <dg...@cc...>]

Hi, all --

I'm highly interested in Q and just tried to install the MacPorts  
version with the following results:

  --->  Fetching pkgconfig
...
--->  Activating zlib 1.2.3_1
Error: Target org.macports.activate returned: Image error: /opt/local/ 
include/zconf.h already exists and does not belong to a registered  
port.  Unable to activate port zlib.
Error: The following dependencies failed to build: curl zlib gmp  
readline ncurses ncursesw
Error: Status 1 encountered during processing.

Any help will be greatly appreciated.
--
Don Groves

Re: [q-lang-users] Speeding up Q

[Libor S. <li...@gm...>]

On Wed, 02 Apr 2008 13:21:43 +0100, Albert Graef <Dr....@t-...> wrote:

> But the biggest difference between all those languages (including Lisp)
> and Q/Pure is that the latter are based on general term rewriting rather
> than the lambda calculus, which essentially boils down to the simple
> feature that there is no distinction between "constructors" and "defined
> functions". 

This is my take on this. Any comments?

Functors (identifiers of defined functions), operators, and constructors are essentially one and the same thing.  After all, we could define new operators by functions ever since Algol68 and there was equivalence between constructors and functors since Prolog .(A,B) = [A,B]. 

So I think you are doing the right and natural thing to acknowledge this and to incorporate it onto your language design by essentially removing those unnecessary distinctions from the matcher requirements as well. At least this is how I understand your 
main point.

Now here is a new idea: 

At the moment, you write (in Q or Pure): square X = X*X;

Suppose that we remove the requirement that any functor/operator/constructor be present on the L.H.S. as well? So now we can, whenever we want to, turn this into an anonymous function (lambda expression):
 X = X*X;
by simply omitting the functor (and possibly using -> instead of =). 
Simply written as any other rule with the = sign, it would become a macro, in this case a dangerously recursive one. However, there is use for ordinary text replacement macros of similar forms.

You could then also write this: var Square = (X = X*X); without the lambda and dot syntactical baggage.
Square is now a function variable, which can be applied simply as: Square X

I like this because it makes very clear and obvious the comparison between the constant function definition square and the
variable function definition Square. Notice that they were both initialised with exactly the same expression/value/R.H.S., the only
difference being that one is a constant and the other is a variable holding the same value.

I know, most of this is just "reinventing" lambda calculus but, at the very least, I think my suggestion could lead to a neater syntax, getting rid of the pesky \ and . which had me puzzled when I first saw them. I had no idea what they were until I was told somewhere deep down the manual, that \ stands for lambda.

Libor

Re: [q-lang-users] Speeding up Q

[Libor S. <li...@gm...>]

On Wed, 02 Apr 2008 13:21:43 +0100, Albert Graef <Dr....@t-...> wrote:

> Btw, this might also be a nice read in this context:
> http://www.lisperati.com/landoflisp/

Wonderful cartoon. I loved that "Hidley Milner Type Checker"!
Holy awesomeness!!! :)

Re: [q-lang-users] Speeding up Q

[Albert G. <Dr....@t-...>]

Brian Beckman wrote:
> Oh, I think I see even more clearly, now. The data constructors "Just" and
> "Nothing" are not quite ordinary functions ... they're a special kind of
> function that is permitted -- by special rules -- to participate in pattern
> matching.  But in TRs, any function is permitted in the pattern position
> because there's just one kind of function.  Right?

Right, exactly. Constructors *only* get used in the patterns, and
functions *only* get used in the head position in front of the patterns.
That is what's called the constructor discipline. Of course, you *can*
program like this with TRSes, too (I think that the term "constructor
discipline" actually comes from TRS theory), but it's not required.
TRSes are therefore conceptually much simpler.

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag

Re: [q-lang-users] Speeding up Q

[Brian B. <bri...@co...>]

Oh, I think I see even more clearly, now. The data constructors "Just" and
"Nothing" are not quite ordinary functions ... they're a special kind of
function that is permitted -- by special rules -- to participate in pattern
matching.  But in TRs, any function is permitted in the pattern position
because there's just one kind of function.  Right?

It always seems right to me to reduce the number of special cases.

-----Original Message-----
From: q-l...@li...
[mailto:q-l...@li...] On Behalf Of Brian
Beckman
Sent: Wednesday, April 02, 2008 5:45 PM
To: 'Discuss the Q language.'
Subject: Re: [q-lang-users] Speeding up Q

I think I see :)  At the risk of being tiresome, I think you're saying that
in something like this in Haskell

data Maybe a = Nothing | Just a

we get a type constructor "Maybe" and a type variable "a" on the left-hand
side, and a pair of data constructors, which are just ordinary functions
(?!) -- on the right-hand side, and "a" gets punned from a type variable on
LHS into an ordinary data-variable of type a on the RHS. At least, that's
how I understand it (perhaps very poorly :) The TYPE constructor, "Maybe,"
is NOT available for Haskell's pattern matching, but the data constructors
are, by design

f :: Num a => Maybe a -> a
f (Just x) = x
f Nothing  = 0

In Q, this distinction doesn't even arise, correct?  And if not, is the
reason that data constructors like "Maybe" don't exist?  And, if so, isn't
the reason simply that a "kinded" type system can't exist in Q or other TRS,
and that type-checking must always be dynamic because and there's only one
KIND of thing (a function) and patterns are perforce just over functions?
Or am I way off?

Apologies for being so far off the deep end :)

 

-----Original Message-----
From: q-l...@li...
[mailto:q-l...@li...] On Behalf Of Albert
Graef
Sent: Wednesday, April 02, 2008 11:13 AM
To: Discuss the Q language.
Subject: Re: [q-lang-users] Speeding up Q

Brian Beckman wrote:
> Would you be so kind as to give a tiny example of a 'constructor' versus a
> 'defined function' to clarify how they're different in the lambda calculus
> but not so in TR?  My memory of lambda is that it's just the following

I should have worded that more carefully. Of course, pure lambda
calculus doesn't have constructor symbols (they're emulated using
lambdas), but Haskell, ML et al have them. I was actually talking about
the constructor discipline in pattern-matching definitions in Haskell et
al. In a sense these are just rewriting rules, but there are two
different classes of symbols, the defined functions which occur as head
symbols in the definitions, and the constructor symbols which occur in
the argument patterns. Consequently, in Haskell, ML etc. there's just no
way you can write a rule like

foo (foo x) = x;

expressing the idempotence of a "function" foo, or

Bar (Bar x y) z = Bar x (Bar y z);

for making a binary "constructor" Bar right-associative. But in TR,
these kinds of rules are just normal business.

In a sense, these are all just conveniences. After all, lambda calculus
is as universal as term rewriting and they can easily emulate each
other. But rewriting rules are just *so* much more convenient, otherwise
why would there be pattern-matching in virtually every modern FPL (and
there's even a Lisp dialect which has them)? TR languages go all they
way there, by just abolishing the artificial segregation between
functions and constructors.

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag

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Re: [q-lang-users] Speeding up Q

[Brian B. <bri...@co...>]

I think I see :)  At the risk of being tiresome, I think you're saying that
in something like this in Haskell

data Maybe a = Nothing | Just a

we get a type constructor "Maybe" and a type variable "a" on the left-hand
side, and a pair of data constructors, which are just ordinary functions
(?!) -- on the right-hand side, and "a" gets punned from a type variable on
LHS into an ordinary data-variable of type a on the RHS. At least, that's
how I understand it (perhaps very poorly :) The TYPE constructor, "Maybe,"
is NOT available for Haskell's pattern matching, but the data constructors
are, by design

f :: Num a => Maybe a -> a
f (Just x) = x
f Nothing  = 0

In Q, this distinction doesn't even arise, correct?  And if not, is the
reason that data constructors like "Maybe" don't exist?  And, if so, isn't
the reason simply that a "kinded" type system can't exist in Q or other TRS,
and that type-checking must always be dynamic because and there's only one
KIND of thing (a function) and patterns are perforce just over functions?
Or am I way off?

Apologies for being so far off the deep end :)

 

-----Original Message-----
From: q-l...@li...
[mailto:q-l...@li...] On Behalf Of Albert
Graef
Sent: Wednesday, April 02, 2008 11:13 AM
To: Discuss the Q language.
Subject: Re: [q-lang-users] Speeding up Q

Brian Beckman wrote:
> Would you be so kind as to give a tiny example of a 'constructor' versus a
> 'defined function' to clarify how they're different in the lambda calculus
> but not so in TR?  My memory of lambda is that it's just the following

I should have worded that more carefully. Of course, pure lambda
calculus doesn't have constructor symbols (they're emulated using
lambdas), but Haskell, ML et al have them. I was actually talking about
the constructor discipline in pattern-matching definitions in Haskell et
al. In a sense these are just rewriting rules, but there are two
different classes of symbols, the defined functions which occur as head
symbols in the definitions, and the constructor symbols which occur in
the argument patterns. Consequently, in Haskell, ML etc. there's just no
way you can write a rule like

foo (foo x) = x;

expressing the idempotence of a "function" foo, or

Bar (Bar x y) z = Bar x (Bar y z);

for making a binary "constructor" Bar right-associative. But in TR,
these kinds of rules are just normal business.

In a sense, these are all just conveniences. After all, lambda calculus
is as universal as term rewriting and they can easily emulate each
other. But rewriting rules are just *so* much more convenient, otherwise
why would there be pattern-matching in virtually every modern FPL (and
there's even a Lisp dialect which has them)? TR languages go all they
way there, by just abolishing the artificial segregation between
functions and constructors.

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag

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[q-lang-users] Speeding up Q

[Libor S. <li...@gm...>]

On Wed, 02 Apr 2008 13:21:43 +0100, Albert Graef <Dr....@t-...> wrote:

> ..... Whether you
> like that pretty much depends on which kind of programmer you are: do
> you want a sharp knife, or are you worried about accidentally cutting
> your feet off? ;-)
>
> Hope that this clarified the differences a bit.
>
> Cheers,
> Albert

Albert,

Thank you for that clear answer! Now I am even more looking forward to trying out Pure. I was never one of those who believe that sharp knives should be banned. That kind of thinking leads to "Hello World!" program in "only" two pages of J... code ;-)

It is often argued that safety is important. In my view, however, those who can program don't need it and those who cannot program only make more mistakes the longer the program is and should be doing something else anyway. 

Libor

Re: [q-lang-users] Speeding up Q

[Albert G. <Dr....@t-...>]

Brian Beckman wrote:
> Would you be so kind as to give a tiny example of a 'constructor' versus a
> 'defined function' to clarify how they're different in the lambda calculus
> but not so in TR?  My memory of lambda is that it's just the following

I should have worded that more carefully. Of course, pure lambda
calculus doesn't have constructor symbols (they're emulated using
lambdas), but Haskell, ML et al have them. I was actually talking about
the constructor discipline in pattern-matching definitions in Haskell et
al. In a sense these are just rewriting rules, but there are two
different classes of symbols, the defined functions which occur as head
symbols in the definitions, and the constructor symbols which occur in
the argument patterns. Consequently, in Haskell, ML etc. there's just no
way you can write a rule like

foo (foo x) = x;

expressing the idempotence of a "function" foo, or

Bar (Bar x y) z = Bar x (Bar y z);

for making a binary "constructor" Bar right-associative. But in TR,
these kinds of rules are just normal business.

In a sense, these are all just conveniences. After all, lambda calculus
is as universal as term rewriting and they can easily emulate each
other. But rewriting rules are just *so* much more convenient, otherwise
why would there be pattern-matching in virtually every modern FPL (and
there's even a Lisp dialect which has them)? TR languages go all they
way there, by just abolishing the artificial segregation between
functions and constructors.

Albert

-- 
Dr. Albert Gr"af
Dept. of Music-Informatics, University of Mainz, Germany
Email:  Dr....@t-..., ag...@mu...
WWW:    http://www.musikinformatik.uni-mainz.de/ag

Re: [q-lang-users] [OT] Upcoming Book: "Gnuplot in Action"

[Philipp K. J. <ja...@ma...>]

 
My apologies - the URL is:
        www.principal-value.com/my-book.php

(3 'w' - instead of 4)

Best,

                Ph.

On 02/04/2008, Philipp K. Janert <ja...@ma...> wrote:
> Finally: A book on Gnuplot!
>
> If you are interested in data analysis and visualization,
> you might be interested in the upcoming book:
>         "Gnuplot in Action"
> (to be published, Fall 2008, Manning Publications).
>
> You can pre-order it directly from the publisher:
>         www.manning.com/janert
>
> Gnuplot is probably the most popular open-source
> program for plotting and visualization. The book
> assumes no previous familiarity with Gnuplot. It
> introduces the most basic concepts rapidly, and
> then moves on to explain Gnuplot's advanced
> concepts and power features in detail.
>
> If you want to learn more about the book and the
> author, check out my book page at
>         wwww.principal-value.com/my-book.php
>
> If you have comments or suggestions for the book,
> please let me know!
>
> Feel free to forward this information as appropriate.
>
> Best,
>
>                 Ph.
> _______________________________________________
> Help-octave mailing list
> Hel...@oc...
> https://www.cae.wisc.edu/mailman/listinfo/help-octave

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