My experience learning Racket (starting from not really knowing any lisp/schemes at all), is that you can do a lot with a simple core. The rest can unfold gradually and simply on an as-needed basis:
1. You need to do X real-world thing, and you find/learn/use Racket's "battery included" to do that. (Where X is net, web, image, GUI or whatever.) 2. What you're writing works, but you're curious if there's another way to express it. I _think_ that's pretty typical for any language? In my experience the only two big "speed bumps" are macros and continuations. I think the issues here are: 1. The mental model is a bigger step up. 2. Terminology soup. I think that's what causes "syntax expand transformer datum splicing #' #, stx blah blah blah Ginger". But actually, this is like my original point. You can write a _lot_ of stuff using syntax-rules etc., which has none of that cognitive load. So this is a box you don't need to open until/unless you're ready. Maybe there's potentially a "marketing problem" if people look at Racket too quickly and the surface area seems too big and complicated, and mistakenly conclude that's a bad thing? But I don't think that's the reality. IMHO. On Sat, Jan 19, 2013 at 4:00 AM, Laurent <laurent.ors...@gmail.com> wrote: > Rüdiger, > > I used to think as you do (for the same reasons and with the same history > you describe), but then I understood that the macro system is still an area > under research. I think PLT and all other Scheme researchers are all willing > to have the simplest and most beautiful definition of a hygienic macro > system (or whatever comes next), but currently Racket's is the best we have > (although I know little about other macro systems, so certainly some people > would disagree). > > Regarding the whole rest of Racket features, bells and whistles, you can > still do without them if you want, but you'll end up redefining them all at > some point. The programmers behind Racket are doing their best to produce > practical yet powerful tools, but hey, they're only human. If you find a > better way to do something they did, just make it a PLaneT package, or fork > the git repository, and discuss the benefits on the mailing list. I'm pretty > sure they're all willing to make Racket better and simpler. > > However, I also agree that Racket is quite complex if you want to know it > all. And collapsing some parts of it into simpler structures might be > difficult because of the required backward compatibility. I wish sometimes > programmers could be able to care less about that. > > Just my own point of view, > Laurent > > > On Fri, Jan 18, 2013 at 9:22 PM, Rüdiger Asche <r...@ruediger-asche.de> > wrote: >> >> Tim, I wholeheartedly agree. Scheme used to be plainly beautiful. >> Understand lambda expressions, recursion and continuations, and everything >> else more or less falls into place. >> >> The Scheme part of Racket still is as cool, but the rest is a moloch. Just >> syntactically understanding a Racket application requires deep digging into >> the guts; when I first picked up Racket after a long absence of Scheme, I >> just couldn't make heads or tails of all the #s, :s, ,s and and %s spread >> all over the place (and I still need to look those up frequently when I >> don't deal with something for a week or more). The macro system is even >> worse for the reasons you describe. Nothing simple, beautiful or orthogonal >> anymore. What a shame. Then take modules, phases and all the other bells and >> whistles (some of which are actually useful, but most appear to be of >> interest more to theoreticians than people involved in solving real >> problems) and you end up with something that takes much more time to get the >> tools to work right before you even get something relatively straightforward >> accomplished with them. >> >> It used to be the case that you could reduce a Scheme system to a very few >> primitives and build the rest around it using syntactic extensions. That may >> still be true in Racket, but dealing with the syntactic extensions >> themselves requires learning a complete new and several times more complexe >> language. Bummer. I just don't see how one would attract newcomers to Racket >> when all the beauty is so obfuscated. >> >> >> ----- Original Message ----- From: "Tim Brown" <tim.br...@cityc.co.uk> >> To: "Matthias Felleisen" <matth...@ccs.neu.edu> >> Cc: "Racket Users" <users@racket-lang.org> >> Sent: Friday, January 18, 2013 6:36 PM >> Subject: Re: [racket] variables within macros >> >> >> >>> On 18/01/13 15:54, Matthias Felleisen wrote: >>>> >>>> Is there a single stumbling block or do you feel overwhelmed by >>>> the broad API to the syntax system? -- Matthias >>> >>> >>> It's a combination of the two... >>> >>> My single stumbling block is "binding" identifiers -- I'm never sure if >>> I'm going to end up with an identifier referencing the same value/entity/ >>> thing. This is because I'm not so used to passing the lexical context >>> around as the macro API (probably) demands. >>> >>> So, in order to get my bindings right, I want to be sure I'm using >>> the right syntax-... calls. And this is where the breadth of the API >>> starts to overwhelm me. >>> >>> There is also the fact that I'm "feeling around" the rest of the racket >>> API >>> to understand the runtime-work that I want my macros to help me with. >>> Trouble is, the more I look into it "runtime" seems to be less like >>> "execute a function" and more like "run another macro"! >>> >>> >>> >>> A concrete example is that I am trying to write a #lang language. Which, >>> I >>> believe (from syntax_module-reader.html) requires me to: >>> (provide (except-out (all-from-out racket) #%module-begin) >>> (rename-out [module-begin #%module-begin])) >>> >>> I also want to (provide define/tested) which defines functions (with >>> racket's define), but also adds a unit test to the function... ala >>> (check-= (add2 2) 4 0 "something descriptive") Racket/raco provides the >>> facility to put that into a "test" module for unit testing. >>> >>> But I find that because I'm tinkering with #%module-begin, simply adding >>> a (module+ test (check-= ...)) clause causes problems. >>> >>> I *think* I'm doing something relatively simple; but there are enough >>> gotchas here to keep me going round in circles. >>> >>> What I have just described is in: >>> https://github.com/tim-brown/plt-games-racket-tested >>> >>> the "minimal-..." code(*), when run leaves me with the error: >>> "check-=: unbound identifier in module in: check-=" >>> >>> To my mind there is nothing wrong! There is either something stupid that >>> I'm missing, or there is something that requires "knowledge of how all of >>> racket works together" (as described above). >>> >>> This is a bit of a big bite to have taken out of the macro system, but I >>> have to start non-triviality somewhere. Equally, though extending the >>> language is something that Racket encourages; and as far as I can tell, >>> this is (or should be) a trivial extension. >>> >>> Thank you for listening :-) >>> >>> Tim >>> >>> * the rest of the code shows evidence of me banging my head against >>> various >>> walls, may be instructive as to what extremes I have gone two, and may >>> also provide amusement; but the minimal-... code is fundamentally where >>> I'm coming stuck. >>> >>> >>> >>>> On Jan 18, 2013, at 6:38 AM, Tim Brown wrote: >>>> >>>>> On 17/01/13 21:33, Greg Hendershott wrote: >>>>>>>> >>>>>>>> Greg Hendershott's pages may be of interest to you: >>>>>>>> http://www.greghendershott.com/fear-of-macros/ >>>>> >>>>> >>>>> Which is as close as I have come to "How to Design Macros" so far. >>>>> >>>>>>> I read that earlier, and it gave me the confidence to get stuck in... >>>>>>> maybe I read it again to give me the insight to know what I'm doing. >>>>>> >>>>>> >>>>>> Well it might help prepare you to understand something like Danny's >>>>>> solution. But unfortunately it doesn't specifically explain local >>>>>> expansion. That was only at the fuzzy edge of my own understanding. >>>>>> Still is: When I read something like Jens' code, my brain still hears >>>>>> "blah blah blah Ginger". >>>>>> <https://www.google.com/search?q=blah+blah+blah+ginger&tbm=isch> >>>>> >>>>> >>>>> Do you _know_ how good it makes me feel that someone else "blah blah >>>>> blah >>>>> Ginger"s with macros? >>>>> >>>>> Went through fear-of-macros AGAIN last night. I think I can cope with >>>>> that! >>>>> It all sounds *so reasonable*... but everything anyone writes about >>>>> macros >>>>> sounds *so reasonable*. Until I put the page down! >>>>> >>>>> I feel like one of those Zen disciples who just doesn't get it. >>>>> But quite often they do. After a while. So I'm keeping up hope. >>>>> >>>>> Tim >>>>> >>>>> -- >>>>> Tim Brown <tim.br...@cityc.co.uk> | City Computing Limited >>>>> | >>>>> T: +44 20 8770 2110 | City House, Sutton Park Road >>>>> | >>>>> F: +44 20 8770 2130 | Sutton, Surrey, SM1 2AE, GB >>>>> | >>>>> >>>>> -----------------------------------------------------------------------| >>>>> BEAUTY: What's in your eye when you have a bee in your hand >>>>> | >>>>> >>>>> -----------------------------------------------------------------------' >>>>> City Computing Limited registered in London No. 1767817. >>>>> Registered Office: City House, Sutton Park Road, Sutton, Surrey, SM1 >>>>> 2AE >>>>> VAT number 372 8290 34. >>>>> ____________________ >>>>> Racket Users list: >>>>> http://lists.racket-lang.org/users >>>> >>>> >>> >>> >>> -- >>> Tim Brown <tim.br...@cityc.co.uk> | City Computing Limited | >>> T: +44 20 8770 2110 | City House, Sutton Park Road | >>> F: +44 20 8770 2130 | Sutton, Surrey, SM1 2AE, GB | >>> -----------------------------------------------------------------------| >>> BEAUTY: What's in your eye when you have a bee in your hand | >>> -----------------------------------------------------------------------' >>> City Computing Limited registered in London No. 1767817. >>> Registered Office: City House, Sutton Park Road, Sutton, Surrey, SM1 2AE >>> VAT number 372 8290 34. >>> ____________________ >>> Racket Users list: >>> http://lists.racket-lang.org/users >> >> >> ____________________ >> Racket Users list: >> http://lists.racket-lang.org/users > > > > ____________________ > Racket Users list: > http://lists.racket-lang.org/users > ____________________ Racket Users list: http://lists.racket-lang.org/users
