[REBOL] Re: Parsing comment
Hi Pat, this is a matter of personal preference. I always use the TO function. (speed, generality) Speaking about personal preferences: I am eliminatig the usage of functions with unevaluated arguments and I suggest everyone to do that (see my Rep for the reasons). The only reason I used them in my example is, that they change the evaluation order in an unexpected way, which is normally a bad thing (IMO - this is another point where my POV differs from Tim Peters'). - Original Message - From: pat665 Hi Ladislav, Could you explain a bit your code ? especially this line print: func ['x] [reduce ['print to paren! x]] Why is it not print: func ['x] [reduce ['print to-paren x]] Ciao Patrick -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi, Gregg, et al, Yet another variation, just for fun, and a profound philosophical comment... ;-) Gregg Irwin wrote: Hi Dick, Hopefully I won't just add more confusion here... 10 + 10 means something to the Rebol interpretation process, but 10+10 does not have the same meaning... If we take the numbers out of the equation :) to avoid syntactical issues, you can do this (because + is a valid character in words): a: 1 == 1 b: 2 == 2 a + b == 3 a+b: 4 == 4 a+b == 4 So, a+b is not the same as a + b. Now, you could also change the operation of +, like this: set '+ :* 1 + 3 == 3 But, AFAIK, you can't alter the operands that an operator operates upon. :) Depends on your definition of alter... a: func [:op 'val] [set val do [op get val get val]] b: 3 == 3 a + b == 6 b == 6 A long time ago I heard someone say FORTH is not a programming language; it is a programming language construction kit! Despite differences in notation and internal representation, the REBOL facility for dailecting, and the absence of distinction between data and code make me think that the same statement could be made of REBOL. Of course, I remember the saying, I've only met one self-made man, and he should have sued the manufacturer for malpractice! ;-) -jn- -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
You guys are titillatingly fun ... Hi, Gregg, et al, Yet another variation, just for fun, and a profound philosophical comment... ;-) Gregg Irwin wrote: Hi Dick, Hopefully I won't just add more confusion here... 10 + 10 means something to the Rebol interpretation process, but 10+10 does not have the same meaning... If we take the numbers out of the equation :) to avoid syntactical issues, you can do this (because + is a valid character in words): a: 1 == 1 b: 2 == 2 a + b == 3 a+b: 4 == 4 a+b == 4 So, a+b is not the same as a + b. Now, you could also change the operation of +, like this: set '+ :* 1 + 3 == 3 But, AFAIK, you can't alter the operands that an operator operates upon. :) Depends on your definition of alter... a: func [:op 'val] [set val do [op get val get val]] b: 3 == 3 a + b == 6 b == 6 A long time ago I heard someone say FORTH is not a programming language; it is a programming language construction kit! Despite differences in notation and internal representation, the REBOL facility for dailecting, and the absence of distinction between data and code make me think that the same statement could be made of REBOL. Of course, I remember the saying, I've only met one self-made man, and he should have sued the manufacturer for malpractice! ;-) -jn- -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes. ** - End Original Message --- ** Download NeoPlanet at http://www.neoplanet.com -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
On 25-Sep-02, Anton wrote: But first, I would say that it's probably silly to start promoting rebol here. We should hang out on other mail lists and catch misinformation where it is usually missed. Fair enough, as long as you don't end up being their local REBOL zealot. Easy to turn people off just by the level of noise you generate. (: -- Carl Read -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Carl Read wrote: (Or can we write operators, for that matter.) ... + 1 2 == 3 1 + 2 == 3 sum: func [a b][a + b] sum 1 2 == 3 1 sum 2 ** Script Error: sum is missing its b argument ** Near: sum 2 Can it be done? We can do something like it (acknowledgements to Gabriele): !=: get first [] And use it like: 0 != 2 == true 4 != 4 == false But I don't know how to make other infix operator functions. It would be nice to have them. I've got at least one application for it. Andrew Martin ICQ: 26227169 http://valley.150m.com/ -- -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi, allow me to jump in. Tim Peters was a regular Rebol list member for quite some time, so he knows what he is speaking about. The comment on function free-formness surprises me like it surprised Gabriele, because anyone can use parens at will. Some expressions really need parentheses for readability. The only trouble with the free-formness is, that the interpreter has got more work to do, which may slow down the interpretation. Operators: I wrote some comments on operators in http://www.rebolforces.com/~ladislav/rep.html - the section on Evaluation Order. Basically, the interpreter considers some words to be slightly different than others - I call them OP-WORDS. Gabriele revealed, that there is an unused OP-WORD !=. If an OP-WORD has a value of the OP! type, it becomes a Rebol operator. -L - Original Message - From: Andrew Martin Carl Read wrote: (Or can we write operators, for that matter.) ... + 1 2 == 3 1 + 2 == 3 sum: func [a b][a + b] sum 1 2 == 3 1 sum 2 ** Script Error: sum is missing its b argument ** Near: sum 2 Can it be done? We can do something like it (acknowledgements to Gabriele): !=: get first [] And use it like: 0 != 2 == true 4 != 4 == false But I don't know how to make other infix operator functions. It would be nice to have them. I've got at least one application for it. Andrew Martin ICQ: 26227169 http://valley.150m.com/ -- -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Carl, On Wednesday, September 25, 2002, 6:53:36 AM, you wrote: CR which is more functional, shall we say, but can we write functions CR that behave like operators? Not AFAIK. Also, the interpreter is really doing tricks, because: set '+ none == none 1 + 2 ** Script Error: Invalid operator: + ** Where: halt-view ** Near: 1 + 2 (This one, for example, didn't allow me to use DO/NEXT to automatically evaluate code in DBMS.r's query language, because I use the words 'AND and 'OR.) Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Andrew, On Wednesday, September 25, 2002, 8:09:38 AM, you wrote: AM And use it like: 0 != 2 AM == true 4 != 4 AM == false That actually works because '!= is defined inside REBOL, to avoid RT folks headaches when switching between C and REBOL. sum: :+ 1 sum 2 ** Script Error: sum expected value2 argument of type: number pair char money date time tuple ** Where: halt-view ** Near: sum 2 AM But I don't know how to make other infix operator functions. It would be AM nice to have them. I've got at least one application for it. Indeed, it would be much better to have a generic mechanism to define/undefine operators. I might want to avoid them for some reason in one expression, so I should be able to disable that processing in some way. Also, if I wanted to add an operator word, I should have a way to add it to the list of words that are considered operators by the interpreter. Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Also, the whole idea is that REBOL is dynamic. It couldn't be if there was punctuation. I.e.: print a + b DOES NOT have a meaning, unless evaluated under some rules and some context. When you use syntax to give meaning (as opposed to context), you are imposing artificial limits. Whether they are useful or not, depends. I think that the point of REBOL is simplifying, also by removing some artificial limits. Of course, IMHO. print a + b would have meaning if evauation order was right to left or parentheses were used print (a+b) Download NeoPlanet at http://www.neoplanet.com -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
which is more functional, shall we say, but can we write functions
that behave like operators? (Or can we write operators, for that
matter.) ...
+ 1 2
== 3
1 + 2
== 3
Seems you would need to have a function definition template much like APL has:
Define R Is lop FUNC rop ; locals {block}
Where R Is (by its presence) indicates the function returns an explicit result
Where lop (by its presence) indicates a left operand
Where rop (by its presence) indicates a right operand
Where FUNC is the name of the dyadic function (in this case)
Some variations as examples:
NILADIC FUNCTION / no RESULT
Define FUNC {block}
NILADIC FUNCTION / with RESULT
Define R Is FUNC {block}
MONADIC FUNCTION / no RESULT
Define FUNC rop {block}
MONADIC FUNCTION / with RESULT
Define R Is FUNC rop {block}
DYADIC FUNCTION / no RESULT
Define lop FUNC rop {block}
DYADIC FUNCTION / with RESULT
Define R Is lop FUNC rop {block}
NOMADIC FUNCTION / no RESULT
Define [lop] FUNC {block}
NOMADIC FUNCTION / with RESULT
Define R Is [lop] FUNC {block}
Now, for a user defined function to simulate the built-in '+' primitive function:
Define R Is a plus b { R is a + b }
The order of evaluation is assumed to be strictly right to left unless overridden with
parens:
5 * 2 plus 2
=20
(5 * 2) plus 2
=12
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[REBOL] Re: Parsing comment
Equinox got to you? :) Very much so! Harvest Moon came early this year and caught me by surprise ;^) ./Jason -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Carl incomprehesible. For this reason, I've never liked the suggestion that the best way to learn REBOL is to look at other people's scripts. It didn't work for me and I doubt it does for a lot of people. Get the guide and start writing scripts would be my suggestion. Yes right. I do see a developing distinction and concensus from this. Python [and ilk] is notable for readability. One can learn a lot of Pythin by reading other peoples code Rebol is first and foremost a writer's language in the same way FORTH is. That's whay it's so good for rapid prototyping and fun too. Pythin is too. In that sense it is very well balanced, but with REBOL one really gets insde teh logic flow in a differnt way. Its 'narrative'. I suppose that's my ways of saying functional. Which raises the question: how well does Rebol scale. What's important with your scripts is to choose good words for your functions and data, something that doesn't always matter as much in other languages. Ideally the words should suggest what they do or the data they represent, but it's not always easy thinking of good ones when you're coding - it can interrupt the flow. I agree. REBOL reminds me often of'Starting Forth' by Leo Brodie. I read it my first Amiga and started learrning JForth [for HMSL]. I he described well the art and importance of selecting the right words. Wish I had my copy to hand. Starting Forth http://www.amazon.com/exec/obidos/ASIN/0138429227/002-1248362-9982457 http://home.earthlink.net/~lbrodie/books.html Once you're reasonably comfortable with REBOL you don't give a second thought about this, though it may be that REBOL's only suitable to certain types of programmers. That said, I haven't heard any major Yes.. What do you think exactly it is that one learns to become comfortable? What do think about REBOL being used as 'first' language and/or for kids? complaints about this from those who've seriously attempted to learn REBOL. Speed, features, documentation and licencing seem to get much more complaints. Agreed thanks for your comments ./Jason -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi, I don't understand your post. I am pretty sure, that even print (a + b) has no meaning in Rebol without a context supplying additional info. Example of an atypical meaning: use [print a] [ print: func ['x] [reduce ['print to paren! x]] a: func ['x 'y] [compose [a (x) (y)]] print (a + b) ] ; == [print (a + b)] Cheers -L - Original Message - Sent: Wednesday, September 25, 2002 5:23 PM Subject: [REBOL] Re: Parsing comment Also, the whole idea is that REBOL is dynamic. It couldn't be if there was punctuation. I.e.: print a + b DOES NOT have a meaning, unless evaluated under some rules and some context. When you use syntax to give meaning (as opposed to context), you are imposing artificial limits. Whether they are useful or not, depends. I think that the point of REBOL is simplifying, also by removing some artificial limits. Of course, IMHO. print a + b would have meaning if evauation order was right to left or parentheses were used print (a+b) -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Brett Thanks to you and others for the careful comments.. its most encouraging. I am sorry that I don't yet know how to write and discuss these topics concisely. I am very interested in REBOL scope as a beginners language. Separate from x-internet dreams and nifty commercial applications, I think primary education is REBOL's 'true' home. So I'd love to keep this topic alive for a while and see if some deeper collective insights can be focused. arguments or even whether it is a function anyway. More than this though, it is a funny comment in the context of educating novice programmers. The trials and tribulations of a parser don't seem relevent to someone learning a language. Sounds like dead on arrival to me, as far as language design goes. This to me implies that the writer is singularly focussed on the design of Python and potential improvements. No real interest in REBOL as far as I can LoL: You don't know how right you are! That was said by Guido Van Rossum, the brilliant and hard working author of Python. He is in so deep with what he is doing, I guess her really does not have time to step back much. He is always clear and decisive and has shown sound judgment. The growth of Python is proof of that. Similar perhaps to Carl Sassenrath's relationship to REBOL, Guido is known respectfully accepted as Python's BDFL [Benevolent Dictatator For Life] Python Conference: The Opening Keynote, 2001 Guido van Rossum, Python's BDFL (Benevolant Dictator for Life), introduced the conference theme, Python Fits Your Brain--not everybody's brain, but at least the brains of those who like it. Guido has always preferred to make the language work well for its adherents (and especially for himself) rather than try to please everybody. Not only programmers but also artists, scientists and teachers are finding Python well suited for their work Make no mistake, Python is a formidable work with very interesting roots: http://www.engin.umd.umich.edu/CIS/course.des/cis400/python/python.html Python is a very new language; in fact it was released by its designer, Guido Van Rossum, in February 1991 while working for CWI also known as Stichting Mathematisch Centrum. Many of Python's features originated from an interpreted language called ABC. Rossum wanted to correct some of ABC's problems and keep some of its features. At the time he was working on the Amoeba distributed operating system group and was looking for a scripting language with a syntax like ABC but with the access to the Amoeba system calls, so he decided to create a language that was generally extensible. Since he had some experience with using Modula-2+, he decided to talk with the designers of Modula-3. Modula-3 is the origin of the syntax and semantics used for exceptions, and some other Python features. In 1989, during the Christmas holidays, he decided to give it a try and design a language which he later called Python. ABC was supposed to be a really easy beginners language [like LOGO]. I recall Guido saying that ABC failed partly becuase he had made the mistake of insisting on use of CAPITAL LETTERS. Much later [1999] he co-wrote an ambitious [$7 million] DARPA grant proposal: Computer Programming for Everyone, usually refrered to as 'CP4E'. Here's the original http://www.python.org/doc/essays/cp4e.html Also some written and oral interviews from around that time: An Interview with Guido van Rossum [Linux Journal,1999] http://www.linuxjournal.com/article.php?sid=5028 Dr. Dobbs NetCast http://technetcast.ddj.com/tnc_play_stream.html?stream_id=240 In the end the CP4E grant project did not happen. But some active traces remain: http://www.python.org/cp4e/ Some of the people on the Edu-Sig list carry the torch brightly, though many not directly in line wiht the CP4E proposal. Some I think are sophsitaicated in their reading and analysis of learning issues. For example, Kirby Urner is a very open-minded developer who contributes to Edu-Sig often, and while working closely with Python, his scope is much wider. Kirby has been developing a curriculum, much of it around learning programming through geometry: http://www.inetarena.com/~pdx4d/ocn/ A good eaxmple of his approach is: [Edu-sig] Update from Urner (Fri, 05 May 2000) http://mail.python.org/pipermail/edu-sig/2000-May/000406.html check the links he gives at the bottom of that page. He also maintains a wonderful site Synergetics on the Web, presenting some of the core insights of Buckminster Fuller http://www.grunch.net/synergetics/ The REBOL language primarily consists of syntactic forms e.g http://blah... is an url!. If you need the In base REBOL, only functions (at evaluation time) imply any sort of grammar (any specific ordering of items in the source input). Though the exception might be the operators +, -, = etc. that's an interesting way to describe it. Just because we can read the source of Andrew's XML function does not mean that the input to it it isn't *real*
[REBOL] Re: Parsing comment
Hi Ladislav, Could you explain a bit your code ? especially this line print: func ['x] [reduce ['print to paren! x]] Why is it not print: func ['x] [reduce ['print to-paren x]] Ciao Patrick - Original Message - From: Ladislav Mecir [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Wednesday, September 25, 2002 3:58 PM Subject: [REBOL] Re: Parsing comment Hi, I don't understand your post. I am pretty sure, that even print (a + b) has no meaning in Rebol without a context supplying additional info. Example of an atypical meaning: use [print a] [ print: func ['x] [reduce ['print to paren! x]] a: func ['x 'y] [compose [a (x) (y)]] print (a + b) ] ; == [print (a + b)] Cheers -L - Original Message - Sent: Wednesday, September 25, 2002 5:23 PM Subject: [REBOL] Re: Parsing comment Also, the whole idea is that REBOL is dynamic. It couldn't be if there was punctuation. I.e.: print a + b DOES NOT have a meaning, unless evaluated under some rules and some context. When you use syntax to give meaning (as opposed to context), you are imposing artificial limits. Whether they are useful or not, depends. I think that the point of REBOL is simplifying, also by removing some artificial limits. Of course, IMHO. print a + b would have meaning if evauation order was right to left or parentheses were used print (a+b) -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes. Etudiant: Wanadoo t'offre le Pack eXtense Haut Dbit soit 150,92 euros d'conomies ! Et pour 1 euro de plus, reois le CD-ROM du jeu Dark Age of Camelot + 1 mois de jeu en rseau offert ! Clique ici : http://www.ifrance.com/_reloc/mail.etudiant -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Just jumping in with a couple thoughts... I'm not sure you're right about people finding REBOL easy to get into though. As with most things, some people go for them like a duck to water. But I wouldn't be surprised if a lot give up on REBOL pretty quick due to it being a little bit too free-form for their liking. I think programming languages, like so many other things in life, may have certain features that people feel are good or bad (universally or otherwise :) but, from a syntactic point of view, people etiher like them or they don't. Sometimes you spend a lot of time with a language and get used to its syntax. Other times it just clicks in your head and you get it right off. Some people like modern art; some don't. Some people like Antonio Gaudi's architecture; some don't. That doesn't mean modern art is bad art or Gaudi's designs are ugly. Some people like hacking, some like UML and lots of process. Neither one is universally better than the other. It depends on the context. I've looked at lots of languages and tools over the years. I can't tell you why the majority of them didn't click with me, but they didn't. REBOL clicked. I *really wanted* Eiffel, Python, and Ruby to click for me, much like I wanted Oberon and Frontier to click for me as environments, but it didn't happen. I can see so much potential in each of them, in different ways, but they just didn't grab me. I still pull them out periodically, and I still look for new things, but REBOL grabbed me - big time. As I drift through my morning fog I think... Is a cordless circular saw better than a Japanses pull saw? Could you design a tool with the strengths of both and neither of their weaknesses? Is pre-fab, or steel frame, construction better than timber-framing? Would you want to build *every* structure using just one of those methods? Is English better than Basque? People can argue the technical merits of tools and languages but, if someone can use them effectively, you can't discount them out of hand. Beyond the technical viability of a tool, language, or process, can you disregard the less scientific aspects, like culture and craft? ...time for more coffee --Gregg -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Dick, On Wednesday, September 25, 2002, 5:23:30 PM, you wrote: run print (a+b) As Ladislav said, it doesn't. It is just a word! followed by a paren! that contains three word!s. (Oh, in your example above there's actually only one word! in the paren!, because you forgot spaces. I'll just consider this a typo...) You can give this any meaning you want in REBOL; by default, REBOL is set up to give it the meaning you would expect by coming from other languages. REBOL relates much more to XML than to other scripting languages... Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Gabriele, print (a+b) As Ladislav said, it doesn't. It is just a word! followed by a paren! that contains three word!s I am not so sure. :-) This is true only if the standard function Load has been called on the original string, but Rebol does not require it: x: to-word print (a + b) ;== print (a + b) t? x ;== word! mold x; == print (a + b) and it can be used almost like all other words. --- Ciao Romano -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
From all of this, I think Tim Peters does make a valid comment. Many newbies have joined the list and left, unable to come to grips with Rebol. I think part of the problem is due to the lack of documented scripts. Sure there are plenty of scripts now in the script library ( and I don't think they were that many when Tim (wink) was on the list which I think was over 2 years ago), but the scripts in general were not written to educate, but to perform some function. And who bothers to document their scripts with the intention that someone will learn something from them?? In an ideal world, Rebol scripts will be self documenting, but to the newbies ( and me ), this is not going to be the case. If the librarian project ever gets off the ground, perhaps this aspect could be addressed. Scripts could be rated on their instructive value. A way to vote perhaps? -- Graham Chiu -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
If the librarian project ever gets off the ground, perhaps this aspect could be addressed. Scripts could be rated on their instructive value. A way to vote perhaps? Or even a special category for tutorial scripts, and an area for function libraries. --Gregg -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
I am trying to understand ... 10 + 10 means something to the Rebol interpretation process, but 10+10 does not have the same meaning, yet you say it can be given different meaning. Are you implying that the expected operands and the attributes of the operands to a built-in primitive function can be respecified? Or are you saying 10+10 can be given new meaning as if though a user-defined function? Help here please? 10 10+10 10 ==10 20 10 OR ==20 20 Dick ** Original Subject: [REBOL] Re: Parsing comment ** Original Sender: Gabriele Santilli [EMAIL PROTECTED] ** Original Date: Wed, 25 Sep 2002 12:37:11 -0500 ** Original Message follows... Hi Dick, On Wednesday, September 25, 2002, 5:23:30 PM, you wrote: run print (a+b) As Ladislav said, it doesn't. It is just a word! followed by a paren! that contains three word!s. (Oh, in your example above there's actually only one word! in the paren!, because you forgot spaces. I'll just consider this a typo...) You can give this any meaning you want in REBOL; by default, REBOL is set up to give it the meaning you would expect by coming from other languages. REBOL relates much more to XML than to other scripting languages... Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes. ** - End Original Message --- ** Download NeoPlanet at http://www.neoplanet.com -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
On 25-Sep-02, Jason Cunliffe wrote: What's important with your scripts is to choose good words for your functions and data, something that doesn't always matter as much in other languages. Ideally the words should suggest what they do or the data they represent, but it's not always easy thinking of good ones when you're coding - it can interrupt the flow. I agree. REBOL reminds me often of'Starting Forth' by Leo Brodie. I read it my first Amiga and started learrning JForth [for HMSL]. I he described well the art and importance of selecting the right words. Wish I had my copy to hand. Starting Forth http://www.amazon.com/exec/obidos/ASIN/0138429227/002-1248362-9982457 http://home.earthlink.net/~lbrodie/books.html I programmed in Forth and LOGO a long time ago, so REBOL's wordy-ness is not a new concept to me. While I think it should scale well, I wonder how easy large programs would be to maintain once the original programmers have moved on. Ummm, is that REBOL code in that block, or someone's dialect? (: Once you're reasonably comfortable with REBOL you don't give a second thought about this, though it may be that REBOL's only suitable to certain types of programmers. That said, I haven't heard any major Yes.. What do you think exactly it is that one learns to become comfortable? The console and all those datatypes make your code easy to test and to trial different ways of doing things. I seem to spend more time searching for the names of REBOL's native words (which this old brain has forgotten again:) than I do in tracking down bugs. What do think about REBOL being used as 'first' language and/or for kids? Tim Johnson would be a better person to ask I think, as he's had some experience of teaching REBOL to kids. I'd think it would have quite a few advantages though, in that it's a functional and extensible language, but you can also treat it as an imperative language if you want. There's objects too, so it could be used for teaching object-oriented programming, but once again, you're not forced to write object-oriented code. Plus there's dialects, so you could use it to teach not only programming, but how to create programming languages as well, which would also teach there's different ways a programming language can be structured. And the total control you have over View, (and I mean View, not VID), would be I think great for teaching GUI design. The downside would be the lack of documentation, (especially for View), plus the lack of experienced REBOL programmers to teach the language. Not a good look when the teacher doesn't know the answer to a question and hasn't the resources to find it. -- Carl Read -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Dick, Hopefully I won't just add more confusion here... 10 + 10 means something to the Rebol interpretation process, but 10+10 does not have the same meaning, yet you say it can be given different meaning. Are you implying that the expected operands and the attributes of the operands to a built-in primitive function can be respecified? Or are you saying 10+10 can be given new meaning as if though a user-defined function? Help here please? If we take the numbers out of the equation :) to avoid syntactical issues, you can do this (because + is a valid character in words): a: 1 == 1 b: 2 == 2 a + b == 3 a+b: 4 == 4 a+b == 4 So, a+b is not the same as a + b. Now, you could also change the operation of +, like this: set '+ :* 1 + 3 == 3 But, AFAIK, you can't alter the operands that an operator operates upon. :) --Gregg -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Romano, On Wednesday, September 25, 2002, 8:36:43 PM, you wrote: RPT This is true only if the standard function Load has been called on the RPT original string, but Rebol does not require it: Of course. :-) But then, any language can be anything, as long as you read the text with your own parser. ;-) Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Dick, On Thursday, September 26, 2002, 2:30:45 AM, you wrote: run 10 + 10 run means something to the Rebol interpretation process, but run 10+10 does not have the same meaning, yet you say it can be length? [a + b] == 3 length? [a+b] == 1 a+b: func [x] [print x] a+b hello hello REBOL needs spaces to separate words. foreach value [a + b] [print type? value] word word word You just have three words. REBOL does not make any assumption on their meaning, like other languages do. foreach value [print (a + b)] [print type? :value] word paren foreach value second [print (a + b)] [print type? :value] word word word This shows what I was saying in the last message. Now, you do whatever you wanted with that block of values, even interpreting it with your own interpreter. Or, you could give those words a meaning different from the usual one (like Ladislav did in his message) and let the REBOL interpreter evaluate it. Still, you can't say that that block block will print the sum of a and b on screen unless you know the context in which the expression is evaluated. (We're already making assumptions, when we talk about expressions and evaluation...) Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Jason, On Monday, September 23, 2002, 6:03:50 AM, you wrote: JC start a language flamewar. Just curious and hoping someone here can explain more JC about parsers. I barely know how to use REBOL's parse, but I like what I know The comment below has noting to do with REBOL's PARSE function. I've not looked much at it personally, but I trust a close colleague who has, and who finds it hard to use because the parser cannot know [...] I.e., he's suggesting that we should use parenthesis like Lisp. My answer is, no comment. (There are a lot of things in REBOL that could be criticized, but this one really makes no sense to me.) Regards, Gabriele. -- Gabriele Santilli [EMAIL PROTECTED] -- REBOL Programmer Amigan -- AGI L'Aquila -- REB: http://web.tiscali.it/rebol/index.r -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Jason wrote: Today I read a comment about REBOL which I don't understand. I am NOT seeking to start a language flamewar. Just curious and hoping someone here can explain more about parsers. I barely know how to use REBOL's parse, but I like what I know about it, and it has a strong reputation in these waters. ...who finds it hard to use because the parser cannot know the end of a function's parameter list -- that's only known at run time, once the function is called. I think your correspondent means the parser that interprets the Rebol dialect, not the 'parse dialect. And I think the colleague is unused to Rebol language with it's no function calling syntax. For example, in Rebol: print 1 + 2 3 In other languages (like Python), the above is something like: print (1 + 2) (I think...) Andrew Martin Who's recall of other languages is fading away in the blinding light of Rebol... ICQ: 26227169 http://valley.150m.com/ -- -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Jason, who has, and who finds it hard to use because the parser cannot know the end of a function's parameter list -- that's only known at run time, once the function is called. Ingo and Tom have pointed out how the the parser that is being referred to is the language parser and why it is difficult to identify a function's arguments or even whether it is a function anyway. More than this though, it is a funny comment in the context of educating novice programmers. The trials and tribulations of a parser don't seem relevent to someone learning a language. Sounds like dead on arrival to me, as far as language design goes. This to me implies that the writer is singularly focussed on the design of Python and potential improvements. No real interest in REBOL as far as I can see here. It indicates a certain assumed world view as far as the way things should work. Rather that writing dead on arrival that person would have done themselves a favour and perhaps learnt something by instead asking the question I wonder if it is appropriate to apply my ideas of language design to REBOL in this instance?. The REBOL language primarily consists of syntactic forms e.g http://blah... is an url!. If you need the In base REBOL, only functions (at evaluation time) imply any sort of grammar (any specific ordering of items in the source input). Though the exception might be the operators +, -, = etc. The whole point about the design of REBOL is, I think, that it is a foundation that enables many languages to be designed (dialects). Dialects are the languages of REBOL where the grammar is made apparent. You can create a dialect/language so that a parser can know where a function ends, etc. It is just that you have to write the parser (PARSE is a tool to assist this). Writing a dialect and a parser for it is worthwhile only if it adds value in some way. For example, some time ago Andrew Martin published his XML script which evalutes a dialect he defined. The result of the evaluation is well formed XML. His dialect added value by enabling a simple syntax to generate XML. VID adds value by enabling a simple syntax to generate visual interfaces for REBOL/View. Just because we can read the source of Andrew's XML function does not mean that the input to it it isn't *real* executable code. In REBOL it is the evaluation of the input which defines the meaning/effect. Andrew's XML function becomes another mezzanine alongside LAYOUT etc. In this way we end up growing REBOL in ways best suit our requirements. I don't know Python, but I'm guessing that the main way to grow Python is through class libraries. REBOL's dialects can be melded together - the like paren! inside VID or a parse rule. They are embedded languages, which has been reported as an extremely powerful way to construct programs. Class libraries tend to interact like oil and water - they don't, your main program has to do it for them. So if we want to learn from Rebol, we must try to learn from other ideas in it, not from the core language design. I guess people will always miss out on varying experiences and things that can be learnt because it it is in fact really hard to let go of pre-conceptions. :^) Regards, Brett. -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Equinox got to you? :) Andrew Martin ICQ: 26227169 http://valley.150m.com/ -- - Original Message - From: Jason Cunliffe [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Tuesday, September 24, 2002 3:36 PM Subject: [REBOL] Re: Parsing comment http://mail.python.org/pipermail/edu-sig/2002-September/002361.html http://mail.python.org/pipermail/edu-sig/2002-September/002362.html http://mail.python.org/pipermail/edu-sig/2002-September/002363.html I dunno what got into me.. must've been the full moon or something! ./Jason -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes. -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi, Jason, From: Jason Cunliffe ... http://mail.python.org/pipermail/edu-sig/2002-September/002362.html ... external quote ... rejoin [some string variable function [param1 param2]] If it gets any longer than that, time for line breaks. Keep each phrase on its own line so it reads like a poem! ... That is wonderful! REBOL poetry for the masses (, but the gurus use REBOL sonnets!). I think Ralph Roberts would like this, too. I guess REBOL's indentation rules (or lack thereof) and syntax (or lack thereof) would probably drive a hard-core Pythoner to drink (at least one who had never been exposed to more functional-like languages). It made me think of another analogy, of sorts, in how we learn language. We start with short phrases, testing them out, and see what response we get. Sometimes, we see that our meaning has been conveyed; other times, not. Sometimes we *unknowingly* carry forward an ambiguous state of knowledge and understanding that only unravels much later. It can be very confusing to the initiate. The ability to work interactively with short commands can be very powerful, easy way to learn and be productive from early on. Some imperative languages (NB: I am not necessarily characterizing Python in this regard) require a process more akin to sentence diagramming. However, instead of decomposing a sentence into its diagram, one would construct the fragments, and then string the fragments into a working whole. The process itself may contribute to developing well-organized, technically correct sentences (or program, by way of the analogy) where errors can be pinpointed more readily, but the learning curve for the initiate is daunting. Proper construction requires vision, planning, and experience. Most of us learn our spoken languages at the command-line console of life. Later, we learn more about proper structure through the implicit method of diagramming in the development of sentences, paragraphs, and topics. I do not know this to be true, but my guess is that some languages have more built-in ambiguity than others. Formalized training in the scientific process helps us to disambiguate language and concepts, but our building blocks are inherently ambiguous (by tradition and culture). REBOL and Python both offer the consoles that ease the learning curve. Both are high level in that we are not having to bake our limestone, so that we can have cement to which we can add to aggregate and build the concrete foundation upon which we build our house (makes me miss assembly language). REBOL allows a decidely more free-form construction that can become James Joyce-ian, and therefore inscrutable to all but the REBOL interpreter and the author :-). Python encourages the sort of structure upon which sky scrappers can be built. These are not absolutes, of course, as we certainly know that James Joyce wrote some impressive novels, and who amongst us believes that we are going to build a sky scrapper by ourselves. The one special quality that REBOL offers over many other languages is the stuff of alchemy: not only the ability to know about itself, but to change itself into something quite different. It is the jump from the hand carved printing block to moveable type. REBOL is not unique in this capacity, of course, nor do many people take advantage of this feature. But like the lawyer who can wiggle his/her words as needed, its nice to know that it *can* be done when needed. ;-) Thanks for sharing your ideas. --Scott Jones -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hmmm. This bounced with the first try. Everyone's a critic... (: Anyway... On 23-Sep-02, Jason Cunliffe wrote: Today I read a comment about REBOL which I don't understand. I am NOT seeking to start a language flamewar. Just curious and hoping someone here can explain more about parsers. I barely know how to use REBOL's parse, but I like what I know about it, and it has a strong reputation in these waters. On Rebol (which to my ears rhymes more with Cobol than with rebel :-), I've not looked much at it personally, but I trust a close colleague who has, and who finds it hard to use because the parser cannot know the end of a function's parameter list -- that's only known at run time, once the function is called. Sounds like dead on arrival to me, as far as language design goes. So if we want to learn from Rebol, we must try to learn from other ideas in it, not from the core language design. Ingo gave a good example of what they were probably on about I think. ie, fee fie foe fum could be any mixture of functions and arguments in REBOL. For those coming from other languages, seeing half a dozen or more words in a line with nothing to distinguish between them other than their letters can be disconcerting. The problem's caused by REBOL being a functional language I guess. If we were forced to use parens everywhere the scripts would look horrible, as apposed to just incomprehesible. For this reason, I've never liked the suggestion that the best way to learn REBOL is to look at other people's scripts. It didn't work for me and I doubt it does for a lot of people. Get the guide and start writing scripts would be my suggestion. What's important with your scripts is to choose good words for your functions and data, something that doesn't always matter as much in other languages. Ideally the words should suggest what they do or the data they represent, but it's not always easy thinking of good ones when you're coding - it can interrupt the flow. Once you're reasonably comfortable with REBOL you don't give a second thought about this, though it may be that REBOL's only suitable to certain types of programmers. That said, I haven't heard any major complaints about this from those who've seriously attempted to learn REBOL. Speed, features, documentation and licencing seem to get much more complaints. -- Carl Read -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
On 24-Sep-02, Jason Cunliffe wrote: http://mail.python.org/pipermail/edu-sig/2002-September/002361.html http://mail.python.org/pipermail/edu-sig/2002-September/002362.html http://mail.python.org/pipermail/edu-sig/2002-September/002363.html I dunno what got into me.. must've been the full moon or something! ./Jason (: A good read anyway, Jason. I'm not sure you're right about people finding REBOL easy to get into though. As with most things, some people go for them like a duck to water. But I wouldn't be surprised if a lot give up on REBOL pretty quick due to it being a little bit too free-form for their liking. But anyway, that last poster's good-things-about-REBOL had this in it: ...the idea of building a cursor into container objects which is then manipulated via side effect... Ummm, pardon? Oh - does he mean the series' index? (Why do the answers come to me /after/ I've written the question and not before?;) -- Carl Read -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
== 3 1 sum 2 ** Script Error: sum is missing its b argument ** Near: sum 2 Can it be done? In a dialect, probably. As normal REBOL behaviour - hopefully not ;^) Brett. -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
On 25-Sep-02, Gabriele Santilli wrote: Also, the whole idea is that REBOL is dynamic. It couldn't be if there was punctuation. I.e.: print a + b DOES NOT have a meaning, unless evaluated under some rules and some context. When you use syntax to give meaning (as opposed to context), you are imposing artificial limits. Whether they are useful or not, depends. I think that the point of REBOL is simplifying, also by removing some artificial limits. And we can have... print + a b which is more functional, shall we say, but can we write functions that behave like operators? (Or can we write operators, for that matter.) ... + 1 2 == 3 1 + 2 == 3 sum: func [a b][a + b] sum 1 2 == 3 1 sum 2 ** Script Error: sum is missing its b argument ** Near: sum 2 Can it be done? -- Carl Read -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
I disagree. :) But first, I would say that it's probably silly to start promoting rebol here. We should hang out on other mail lists and catch misinformation where it is usually missed. For this reason, I've never liked the suggestion that the best way to learn REBOL is to look at other people's scripts. It didn't work for me and I doubt it does for a lot of people. Get the guide and start writing scripts would be my suggestion. I learned a lot by reading other people's code on this mail list and from their rebsites. Anton. -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
[REBOL] Re: Parsing comment
Hi Jason, this comment is not directed at the rebol parse word, but at the internal parser which parses a script to execute it. So what he weans is the following: fee fie foe fum may be a valid line in a Rebol script. But you don't know from first view what happens here: are these 4 functions, run one after another? Is it one function with 3 arguments? Is it a function with 2 arguments, where the second argument is first calculated by another function with one argument? Or what? Only the parser knows at execution time, or the one who knows the words by heart. In Python the line might look like: fee( fie foe( fum)) where you can instantly see, that fee is a function of 2 arguments, and where the second argument is computed by foe, a function with one argument. Now in Rebol, due to it's LISPy nature, you could write it like: (fee fie (foe fum)) to give you the same visual feedback, but you aren't forced to use the parentheses, so most people don't most of the time, except when the expression becomes too complicated. I hope that sheds a little light on the subject. Kind regards, Ingo Am Mon, 2002-09-23 um 06.03 schrieb Jason Cunliffe: Today I read a comment about REBOL which I don't understand. I am NOT seeking to start a language flamewar. Just curious and hoping someone here can explain more about parsers. I barely know how to use REBOL's parse, but I like what I know about it, and it has a strong reputation in these waters. On Rebol (which to my ears rhymes more with Cobol than with rebel :-), I've not looked much at it personally, but I trust a close colleague who has, and who finds it hard to use because the parser cannot know the end of a function's parameter list -- that's only known at run time, once the function is called. Sounds like dead on arrival to me, as far as language design goes. So if we want to learn from Rebol, we must try to learn from other ideas in it, not from the core language design. The context behind this is I have been engaged in a some intense debate on the Python-oriented Edu-Sig list. I love Python, but tried point out the obstacles I think it presents to very novice programmers. I mentioned REBOL, giving a contrasting example of how direct and friendly REBOL's help command is. Mainly because it includes a search function. Simple idea, but incedibly friendly effective result. My scenarios was of novice python student trying to determine the current working directory. Where am I? ? d ? dir ? what-dir Python by contrast is great for hackers, and should be great for students. It has all kinds of super-duper tools a for browsing docstrings, and object introspection, but it can be initially overwhelming or useless, until you know exactly what to type, you can find yourself a few screenfulls later before your get the golden answers. In Python to answer the question where am I? you have import a module, then invoke one of its methods. Very Easy when you know how, but obscure as hell when you don't: import os os.getcwd() 'C:\\Python22' Thanks ./Jason -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes. -- To unsubscribe from this list, please send an email to [EMAIL PROTECTED] with unsubscribe in the subject, without the quotes.
