Re: [R] Lisp-like primitives in R
François Pinard wrote: [Roland Rau] [François Pinard] I wonder what happened, for R to hide the underlying Scheme so fully, at least at the level of the surface language (despite there are hints). To further foster portability, we chose to write R in ANSI C Yes, of course. Scheme is also (often) implemented in C. I meant that R might have implemented a Scheme engine (or part of a Scheme engine, extended with appropriate data types) with a surface language (nearly the S language) which is purposely not Scheme, but could have been. If the gap is not extreme, one could dare dreaming that the Scheme engine in R be completed, and Scheme offered as an alternate extension language. If you allow me to continue dreaming awake -- they told me they will let me free as long as I do not get dangerous! :-) -- part of the interest lies in the fact there are excellent Scheme compilers. If we could only find or devise some kind of marriage between a mature Scheme and R, so to speed up the non-vectorisable parts of R scripts... Well, depending on what you want, this is either trivial or impossible... The internal storage of R is still pretty much equivalent to scheme. E.g. try this: r2scheme - function(e) if (!is.recursive(e)) deparse(e) else c((, unlist(lapply(as.list(e), r2scheme)), )) paste(r2scheme(quote(for(i in 1:4)print(i))), collapse= ) [1] ( for i ( : 1 4 ) ( print i ) ) and a parser that parses a similar language to R internal format is not a very hard exercise (some care needed in places). However, replacing the front-end is not going to make anything faster, and the evaluation engine in R does a couple of tricks which are not done in Scheme, notably lazy evaluation, and other forms of non-local evaluation, which drives optimizers crazy. Look up the writings of Luke Tierney on the matter to learn more. If we are lucky and one of the original authors reads this thread they might explain the situation further and better [...]. In r-devel, maybe! We would be lucky if the authors really had time to read r-help. :-) -- O__ Peter Dalgaard Øster Farimagsgade 5, Entr.B c/ /'_ --- Dept. of Biostatistics PO Box 2099, 1014 Cph. K (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
On 9/8/07, Peter Dalgaard [EMAIL PROTECTED] wrote: François Pinard wrote: [Roland Rau] [François Pinard] I wonder what happened, for R to hide the underlying Scheme so fully, at least at the level of the surface language (despite there are hints). To further foster portability, we chose to write R in ANSI C Yes, of course. Scheme is also (often) implemented in C. I meant that R might have implemented a Scheme engine (or part of a Scheme engine, extended with appropriate data types) with a surface language (nearly the S language) which is purposely not Scheme, but could have been. If the gap is not extreme, one could dare dreaming that the Scheme engine in R be completed, and Scheme offered as an alternate extension language. If you allow me to continue dreaming awake -- they told me they will let me free as long as I do not get dangerous! :-) -- part of the interest lies in the fact there are excellent Scheme compilers. If we could only find or devise some kind of marriage between a mature Scheme and R, so to speed up the non-vectorisable parts of R scripts... Well, depending on what you want, this is either trivial or impossible... The internal storage of R is still pretty much equivalent to scheme. E.g. try this: r2scheme - function(e) if (!is.recursive(e)) deparse(e) else c((, unlist(lapply(as.list(e), r2scheme)), )) paste(r2scheme(quote(for(i in 1:4)print(i))), collapse= ) [1] ( for i ( : 1 4 ) ( print i ) ) Also see showTree in codetools: library(codetools) showTree(quote(for(i in 1:4)print(i))) (for i (: 1 4) (print i)) __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
[Peter Dalgaard] [François Pinard] I meant that R might have implemented a Scheme engine [...] with a surface language [...] which is purposely not Scheme, but could have been. [...] one could dare dreaming that the Scheme engine in R be completed, and Scheme offered as an alternate extension language. [...] there are excellent Scheme compilers. [...] Well, depending on what you want, this is either trivial or impossible... I'm more leaning on the impossible side :-). The internal storage of R is still pretty much equivalent to scheme. R needs a few supplementary data types, and it motivated the R authors into re-implementing their own Scheme engine instead of relying on an existing implementation of a Scheme system. r2scheme - function(e) [...] Nice exercise! :-) a parser that parses a similar language to R internal format is not a very hard exercise (some care needed in places). However, replacing the front-end is not going to make anything faster, Of course. The idea is nothing more than to please people starving to use Scheme instead of S as a surface language, here and there in scripts. I merely thought that if the gap is small enough (so to not require an extraordinary effort), it would be worth the leap. One immediate difficulty to foresee is the name clashes between R and RnRS. There might also be missing things in R (like continuations, say). To make anything faster, and this is a totally different idea, one might consider replacing the back-end, not the front-end. Writing good optimizing Scheme compilers is quite an undertaking, and if one only considers type inference (as a subproblem), this still is an active research area. The Scheme engine in R was written as to quickly get a working S (non-obstant lexical scoping and some library issues). My ramble was about switching this quick base of R to some solid Scheme implementation, than to re-address separately compiling issues for R. and the evaluation engine in R does a couple of tricks which are not done in Scheme, notably lazy evaluation, Promises? Aren't they already part of Scheme? The main difference I saw is their systematic use in R argument passing. All aspects of mere argument passing would require a lot of thought. As you wrote, variable scope is another difficulty. Offering a compatible C API, and library interface in general, might be a frightening but necessary challenge. It's all more of a dream than a thought, actually... :-) Look up the writings of Luke Tierney on the matter to learn more. Thanks for this interesting reference. -- François Pinard http://pinard.progiciels-bpi.ca __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
[Duncan Murdoch] You could also look at Ross Ihaka's paper that is online here: http://cran.r-project.org/doc/html/interface98-paper/paper.html Interesting read. Thanks for this reference! -- François Pinard http://pinard.progiciels-bpi.ca __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
[Roland Rau] [François Pinard] I wonder what happened, for R to hide the underlying Scheme so fully, at least at the level of the surface language (despite there are hints). To further foster portability, we chose to write R in ANSI C Yes, of course. Scheme is also (often) implemented in C. I meant that R might have implemented a Scheme engine (or part of a Scheme engine, extended with appropriate data types) with a surface language (nearly the S language) which is purposely not Scheme, but could have been. If the gap is not extreme, one could dare dreaming that the Scheme engine in R be completed, and Scheme offered as an alternate extension language. If you allow me to continue dreaming awake -- they told me they will let me free as long as I do not get dangerous! :-) -- part of the interest lies in the fact there are excellent Scheme compilers. If we could only find or devise some kind of marriage between a mature Scheme and R, so to speed up the non-vectorisable parts of R scripts... If we are lucky and one of the original authors reads this thread they might explain the situation further and better [...]. In r-devel, maybe! We would be lucky if the authors really had time to read r-help. :-) -- François Pinard http://pinard.progiciels-bpi.ca __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
Reduce, Filter and Map are part of R 2.6.0. Try ?Reduce On 9/6/07, Chris Elsaesser [EMAIL PROTECTED] wrote: I mainly program in Common Lisp and use R for statistical analysis. While in R I miss the power and ease of use of Lisp, especially its many primitives such as find, member, cond, and (perhaps a bridge too far) loop. Has anyone created a package that includes R analogs to a subset of Lisp functions? Chris Elsaesser, PhD Principal Scientist, Machine Learning SPADAC Inc. 7921 Jones Branch Dr. Suite 600 McLean, VA 22102 703.371.7301 (m) 703.637.9421 (o) __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
Not all of us are familiar with lisp (I have done a little, but not enough to really understand what you are asking). If you tell us what find, member, cond, and loop do, or what functionality you are looking for, then we will have a better chance of telling you how to do the same in R. Just guessing by the names: The 'which' function may do something similar to 'find'. 'is.element' or '%in%' may do the same as 'member'. 'ifelse' and/or 'switch' may do what 'cond' does. 'replicate', 'lapply', 'sapply', 'while', and 'for' may give the functionality of 'loop'. Those are just guesses based on the names, I don't know what exactly they do, so if I am way off, then tell us what you want them to do. -- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare [EMAIL PROTECTED] (801) 408-8111 -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chris Elsaesser Sent: Thursday, September 06, 2007 11:26 AM To: r-help@stat.math.ethz.ch Subject: [R] Lisp-like primitives in R I mainly program in Common Lisp and use R for statistical analysis. While in R I miss the power and ease of use of Lisp, especially its many primitives such as find, member, cond, and (perhaps a bridge too far) loop. Has anyone created a package that includes R analogs to a subset of Lisp functions? Chris Elsaesser, PhD Principal Scientist, Machine Learning SPADAC Inc. 7921 Jones Branch Dr. Suite 600 McLean, VA 22102 703.371.7301 (m) 703.637.9421 (o) __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
[Chris Elsaesser] I mainly program in Common Lisp and use R for statistical analysis. While in R I miss the power and ease of use of Lisp, especially its many primitives such as find, member, cond, and (perhaps a bridge too far) loop. Has anyone created a package that includes R analogs to a subset of Lisp functions? [Greg Snow] Not all of us are familiar with lisp [...] If you tell us what find, member, cond, and loop do, or what functionality you are looking for, then we will have a better chance of telling you how to do the same in R. Hi, my fRiends :-). So far that I understand, R is built over what originally was a Scheme engine. Scheme may be seen as a flavour of LISP (yet I know people that would strongly object seeing Scheme and Lisp in the same statement :-). But it makes it rather likely that most functions you want already exist in R, even if under different names or syntax. I wonder what happened, for R to hide the underlying Scheme so fully, at least at the level of the surface language (despite there are hints). Wouldn't it have been natural to have the underlying Scheme exposed as an extension language for R, so one might write Scheme functions just as well as C or FORTRAN functions? Is the engine so far from a real Scheme implementation, that such an idea was never reasonable? About the idea of Lisp-inspired library functions... Many Lisp flavours, Common Lisp likely included, have a comprehensive (tremendous?) set of primitives and library functions. By comparison, Scheme is quite moderate, and does not go much beyond the essentials, something which much pleases me :-). There also are many important differences between Common Lisp and Scheme (like for example, global dynamic scoping versus textual scoping). If R was ever to offer Lisp-like interfaces, RnRS (Scheme standards) might be considered, both for being simpler, and more in the spirit of what R already is. -- François Pinard http://pinard.progiciels-bpi.ca __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
François Pinard wrote: I wonder what happened, for R to hide the underlying Scheme so fully, at least at the level of the surface language (despite there are hints). As far as I understood, the original version of Ihaka/Gentleman was written in Scheme. But even if you look at the source version of R 0.49 (the oldest I can find), the source files are written in C. In addition, in their article published in Journal of Computational and Graphical Statistics in 1996, Ihaka and Gentleman write on page 307: To further foster portability, we chose to write R in ANSI C Hope this clarifies the situation a bit. If we are lucky and one of the original authors reads this thread they might explain the situation further and better (and probably correct me). Best, Roland __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
Re: [R] Lisp-like primitives in R
On 06/09/2007 7:36 PM, Roland Rau wrote: François Pinard wrote: I wonder what happened, for R to hide the underlying Scheme so fully, at least at the level of the surface language (despite there are hints). As far as I understood, the original version of Ihaka/Gentleman was written in Scheme. But even if you look at the source version of R 0.49 (the oldest I can find), the source files are written in C. In addition, in their article published in Journal of Computational and Graphical Statistics in 1996, Ihaka and Gentleman write on page 307: To further foster portability, we chose to write R in ANSI C Hope this clarifies the situation a bit. If we are lucky and one of the original authors reads this thread they might explain the situation further and better (and probably correct me). You could also look at Ross Ihaka's paper that is online here: http://cran.r-project.org/doc/html/interface98-paper/paper.html R was written in C, with the intention that it be Scheme-like. Duncan Murdoch __ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
