Actually, this metaphor has been used before. Check http://www.defmacro.org/ramblings/lisp.html for an other version of your story ;).
2010/9/8 alux <alu...@googlemail.com>: > Hello, > > I still try to read my way through Paul Grahams "On Lisp", and always > think how to motivate this stuff to my fellow Java people. How do I > describe what it is all about in this "Code is Data", and "Macros let > you grow your own language towards the problem" stuff? > [Why? Well, maybe I read to much of Paul Grahams texts. So my current > working hypothesis is that this is the one big strength of Lisp that > other languages still dont have - so if I want to motivate people to > learn a Lisp, I have to at least point to it.] > > Short answer: Difficult. ;-) > > Especially if I find formulations like > "You can have the language which suits your program, even if it ends > up looking quite different from Lisp." > > Longer Answer: > > What puzzles me most about this quoted formulation is the words > "different from Lisp", as I know: All my Java collegues see > Lisp=Parentheses. So, to them, PGs formulation is even misleading. To > them it doesn't look quite different at the end. > > Thus I try to come up with a metaphor, and I want to discuss it here, > in the hope I don't tell them rubbish at the end. > > I want to liken XML to Lisp data. Then, with XSLT, some XML structures > are actually programs. Programs that work on XML data. The Lisp > parentheses are just like the basic XML syntax - elements, tags, > attributes. Obviousely Lisp has a much simpler syntax, but its trees > anyway. So XSLT can be likened to Lisp macros then. > > And the use of it? Well, I currently want to talk to some people who > use Maven a lot. So the example I came up with is: > Think about when you had Ant, some years ago. Ant is just a > programming language for Java builds. > After a while you recognise that it'd be better to have something that > describes the project declaratively, with opinionated defaults. Well, > after some discussions you define something called pom.xml, that does > this (congratulation, we just invented Maven). Immediately you see > that all these Ant build scripts mentioned above could be generated > from this Maven pom.xml. So you might write XSLT to do so (this of > course deviates from historical truth). Some step later, you don't > generate them anymore as files; the only needed file is the pom.xml, > and the transformations of course. > > So XML and XSLT are data and code, and they can do something that is > a) similar to what Lisp macros do, and > b) this is something my collegues understand. > > Hopefully. > > So, coming back to Paul Grahams quote, what the beginners see is: It > was XML and stays XML. The things "looking quite different" are, in > this metaphor, the XML schema of the Maven pom.xml versus the XML > scheme of the Ant files. > > I hope that they will understand the power; and agree they will never > try and do this in XSLT. The Lisp syntax is just simple enough to be > usable for such tasks. > > So, now you probably understand why I ask this question here, even if > it is a general Lisp question. This may be the only group where people > understand Lisp and Macros, XML/XSLT, and Ant, and Maven ;-) > > Now the question: > Do you see any problems with this metaphor, is it misleading > somewhere? > > Thank you, alux > > -- > You received this message because you are subscribed to the Google > Groups "Clojure" group. > To post to this group, send email to clojure@googlegroups.com > Note that posts from new members are moderated - please be patient with your > first post. > To unsubscribe from this group, send email to > clojure+unsubscr...@googlegroups.com > For more options, visit this group at > http://groups.google.com/group/clojure?hl=en -- Linux-user #496644 (http://counter.li.org) - first touch of linux in 2004 Demandoj en aŭ pri Esperanto? Questions about Esperanto? Vragen over Esperanto? Perguntas sobre o Esperanto? - http://demandoj.tk -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
