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Show HN: I'm writing a leanpub book about Common Lisp web programming

107 points by pavelludiq 14y ago

pavelludiq 14y ago
Link to leanpub page: https://leanpub.com/lispwebtales https://leanpub.com/lispwebtales
pavelpanev2 14y ago
Why not use Thinatra?
parennoob 14y ago
Wow, definitely something I am going to check out. From a quick look, it seems that your Lisp code for the example looks a lot like HTML itself. For example: (defun blogpage (&optional (posts *posts*)) (html-frame "Restas Blogdemo" (<:div (<:a :href (genurl 'add) "Add a blog post") (<:hr) (render-posts posts)))) I don't know much about functional programming though, so sorry if that's an incorrect assumption.
- pavelludiq 14y ago
  Functions starting with <: are generated by the sexml library for outputting xml and html from lisp expressions. There are many similar libraries in pretty much every lisp dialect.
- aerique 14y ago
  See cl-who for another example: http://weitz.de/cl-who/#syntax http://weitz.de/cl-who/#syntax Also, this has nothing to do with functional programming but rather with creating a DSL (http://en.wikipedia.org/wiki/Domain-specific_language http://en.wikipedia.org/wiki/Domain-specific_language) More links: • http://www.tfeb.org/lisp/hax.html#HTOUT http://www.tfeb.org/lisp/hax.html#HTOUT • https://github.com/franzinc/aserve/blob/master/htmlgen/test.cl https://github.com/franzinc/aserve/blob/master/htmlgen/test....
  - parennoob 14y ago
    Ah, thanks. That was very helpful, specially the second link.
- gcr 14y ago
  Most of the Lisp web frameworks look like that, taking advantage of Lisp's flexible syntax. Here's a Racket example. If you download http://racket-lang.org http://racket-lang.org, you can just run this (no extra libraries or anything) and a browser window will pop up for you. #lang web-server/insta ;; A "hello world" web server (define (start request) (response/xexpr '(html (body (h1 "Hello, world!") (a ([href "http://google.com"]) "Google") (br) "I hope you like my site!")))) This example renders as: <html><body><h1>Hello, world!</h1><a href="http://google.com>Google</a><br http://google.com>Google</a><br />I hope you like my site!</body></html> See also: http://docs.racket-lang.org/continue/ http://docs.racket-lang.org/continue/
  - shn 14y ago
    I need help understanding one thing. This code generates HTML code. Fine. But how come code and declaration (web designer and developer) are separated with this. Is this a good practice? I've been reading about lisp for a long time, not in depth, but I keep stumbling similar snippets a lot. Are there any good examples out there? I am teaching myself Clojure (reading the book with the bird cover) these days.
    - jwr 14y ago
      They are not separated. This approach appeals to geeks/programmers, but is completely impractical, as I've learned the hard way in several projects. In a practical setting you will get a set of pre-cut HTML/CSS and images. Good luck splitting that into semantic markup and styling. And good luck teaching a designer how to work with it afterwards. Because of hard-earned experience I try very hard not to put any HTML into my code, keeping it all in templates, which are much more accessible to designers and easier to modify.
      - muraiki 14y ago
        Yes, this is exactly why I stayed away from things like this, despite my love for Racket and Clojure, until someone above pointed out the Enlive library. It lets you use normal HTML files as your templates but requires no code in it (not even for loops!) Basically, you use CSS-style selectors to replace the contents of elements, giving you the full power of Clojure but without having to either put code in your templates or put HTML into your code. https://github.com/swannodette/enlive-tutorial/ https://github.com/swannodette/enlive-tutorial/
nnq 14y ago
What would the case for CL+Hunchentoot+... vs. Clojure+Noir+... sound like?
- pavelludiq 14y ago
  In general if you prefer FP, clojure is a great choice. If you like multi-paradigm, and mixing up OO with FP, and procedural as you see fit, go with CL. I'm a multi-paradigm kind of guy, but clojure remains my second favorite language :)
ScottBurson 14y ago
Great! When you're done with this, can you be persuaded to write one about Weblocks? I'm kidding, but not entirely. Weblocks is an extremely powerful and sophisticated framework, but it has a bit of a learning curve. It desperately needs a good tutorial.
serichsen 14y ago
You can actually get quite far just with Hunchentoot (and even its built-in "easy handlers"), CL-WHO and some Parenscript.
- pavelludiq 14y ago
  Many lispers prefer to roll their own thin layers on top of hunchentoot, or even use it raw, but I prefer the slightly ticker layer of restas.
tbirdz 14y ago
An incredible coincidence -- I was starting to look into common lisp web programming just this morning, for a personal project. Do you have any estimate on when the book will be finished?
z3phyr 14y ago
Clojure buster? Great!
Su-Shee 14y ago
You should add a section about how a beginner is supposed to install all the components you're using. Right now, you're treating it like they're all "just there".
- pavelludiq 14y ago
  It's in the appendix A: http://lispwebtales.ppenev.com/chap06.html#appendix-a-getting-started http://lispwebtales.ppenev.com/chap06.html#appendix-a-gettin...
- pnathan 14y ago
  I also want to put in a plug for my site: http://articulate-lisp.com/ http://articulate-lisp.com/ :)
nnq 14y ago
Is there any Django/Jinja-like templating engine for CL or Clojure? ...this way or the Clojure Hiccup way is cool for an ubergeek doing full-stack development, but in the real world you'll want your HTML templates separate and in a designer or front-end-coder friendly format. Otherwise, you may have the full power of Lisp at your fingertips, but you'll need to have your entire team used to this workflow and knowledgeable of Lisp, and by having logic in templates and such you're dangerously close to leaning towards the "PHP way". ...the only realistic "homogenous" solution for one language on the server and the client are the Javascript based way, in the Node ecosystem. Good designers or good front-end guys in general will also have coding skills, some will be Javascript gurus, but by doing things this way and writing Javascript code in Parenscript/Clojure script you'll have to force them to learn Lisp in order to work at 100%. And my bet is that they're not gonna like it, so team-wise, you'll lose all the productivity increase you gain in the first place by using Lisp. IF you can find a team of lispers that also have webdesign and frontend coding skills, great, but this will be fucking hard as far as I know it. I would just love working in such an environment, but it seems like a non-existent Nirvana right now...
- pavelludiq 14y ago
  There is a port of Googles closure-template system. It compiles closure templates to CL functions. They work pretty well. I have written about them in the book: http://lispwebtales.ppenev.com/chap04.html#closure-template http://lispwebtales.ppenev.com/chap04.html#closure-template It also compiles to js, so you can even share templates between the client and the backend. I'm experimenting with using both sexml and closure-template, but in the book I use almost exclusively sexml to make the code simpler. Also s-expressions are much easier to type in than sgml :)
- juliangamble 14y ago
  > but in the real world you'll want your HTML templates separate and in a designer or front-end-coder friendly format. For Clojure - it sounds like you're looking for Christophe Grand's work on enlive: https://github.com/cgrand/enlive https://github.com/cgrand/enlive You can read a tutorial here: https://github.com/swannodette/enlive-tutorial/ https://github.com/swannodette/enlive-tutorial/

107 points by pavelludiq 14y ago

pavelludiq 14y ago

Link to leanpub page: https://leanpub.com/lispwebtales https://leanpub.com/lispwebtales

pavelpanev2 14y ago

Why not use Thinatra?

parennoob 14y ago

Wow, definitely something I am going to check out. From a quick look, it seems that your Lisp code for the example looks a lot like HTML itself. For example: (defun blogpage (&optional (posts *posts*)) (html-frame "Restas Blogdemo" (<:div (<:a :href (genurl 'add) "Add a blog post") (<:hr) (render-posts posts)))) I don't know much about functional programming though, so sorry if that's an incorrect assumption.

pavelludiq 14y ago
Functions starting with <: are generated by the sexml library for outputting xml and html from lisp expressions. There are many similar libraries in pretty much every lisp dialect.
aerique 14y ago
See cl-who for another example: http://weitz.de/cl-who/#syntax http://weitz.de/cl-who/#syntax Also, this has nothing to do with functional programming but rather with creating a DSL (http://en.wikipedia.org/wiki/Domain-specific_language http://en.wikipedia.org/wiki/Domain-specific_language) More links: • http://www.tfeb.org/lisp/hax.html#HTOUT http://www.tfeb.org/lisp/hax.html#HTOUT • https://github.com/franzinc/aserve/blob/master/htmlgen/test.cl https://github.com/franzinc/aserve/blob/master/htmlgen/test....
- parennoob 14y ago
  Ah, thanks. That was very helpful, specially the second link.
gcr 14y ago
Most of the Lisp web frameworks look like that, taking advantage of Lisp's flexible syntax. Here's a Racket example. If you download http://racket-lang.org http://racket-lang.org, you can just run this (no extra libraries or anything) and a browser window will pop up for you. #lang web-server/insta ;; A "hello world" web server (define (start request) (response/xexpr '(html (body (h1 "Hello, world!") (a ([href "http://google.com"]) "Google") (br) "I hope you like my site!")))) This example renders as: <html><body><h1>Hello, world!</h1><a href="http://google.com>Google</a><br http://google.com>Google</a><br />I hope you like my site!</body></html> See also: http://docs.racket-lang.org/continue/ http://docs.racket-lang.org/continue/
- shn 14y ago
  I need help understanding one thing. This code generates HTML code. Fine. But how come code and declaration (web designer and developer) are separated with this. Is this a good practice? I've been reading about lisp for a long time, not in depth, but I keep stumbling similar snippets a lot. Are there any good examples out there? I am teaching myself Clojure (reading the book with the bird cover) these days.
  - jwr 14y ago
    They are not separated. This approach appeals to geeks/programmers, but is completely impractical, as I've learned the hard way in several projects. In a practical setting you will get a set of pre-cut HTML/CSS and images. Good luck splitting that into semantic markup and styling. And good luck teaching a designer how to work with it afterwards. Because of hard-earned experience I try very hard not to put any HTML into my code, keeping it all in templates, which are much more accessible to designers and easier to modify.
    - muraiki 14y ago
      Yes, this is exactly why I stayed away from things like this, despite my love for Racket and Clojure, until someone above pointed out the Enlive library. It lets you use normal HTML files as your templates but requires no code in it (not even for loops!) Basically, you use CSS-style selectors to replace the contents of elements, giving you the full power of Clojure but without having to either put code in your templates or put HTML into your code. https://github.com/swannodette/enlive-tutorial/ https://github.com/swannodette/enlive-tutorial/

nnq 14y ago

What would the case for CL+Hunchentoot+... vs. Clojure+Noir+... sound like?

pavelludiq 14y ago
In general if you prefer FP, clojure is a great choice. If you like multi-paradigm, and mixing up OO with FP, and procedural as you see fit, go with CL. I'm a multi-paradigm kind of guy, but clojure remains my second favorite language :)

ScottBurson 14y ago

Great! When you're done with this, can you be persuaded to write one about Weblocks? I'm kidding, but not entirely. Weblocks is an extremely powerful and sophisticated framework, but it has a bit of a learning curve. It desperately needs a good tutorial.

serichsen 14y ago

You can actually get quite far just with Hunchentoot (and even its built-in "easy handlers"), CL-WHO and some Parenscript.

pavelludiq 14y ago
Many lispers prefer to roll their own thin layers on top of hunchentoot, or even use it raw, but I prefer the slightly ticker layer of restas.

tbirdz 14y ago

An incredible coincidence -- I was starting to look into common lisp web programming just this morning, for a personal project. Do you have any estimate on when the book will be finished?

z3phyr 14y ago

Clojure buster? Great!

Su-Shee 14y ago

You should add a section about how a beginner is supposed to install all the components you're using. Right now, you're treating it like they're all "just there".

pavelludiq 14y ago
It's in the appendix A: http://lispwebtales.ppenev.com/chap06.html#appendix-a-getting-started http://lispwebtales.ppenev.com/chap06.html#appendix-a-gettin...
pnathan 14y ago
I also want to put in a plug for my site: http://articulate-lisp.com/ http://articulate-lisp.com/ :)

nnq 14y ago

Is there any Django/Jinja-like templating engine for CL or Clojure? ...this way or the Clojure Hiccup way is cool for an ubergeek doing full-stack development, but in the real world you'll want your HTML templates separate and in a designer or front-end-coder friendly format. Otherwise, you may have the full power of Lisp at your fingertips, but you'll need to have your entire team used to this workflow and knowledgeable of Lisp, and by having logic in templates and such you're dangerously close to leaning towards the "PHP way". ...the only realistic "homogenous" solution for one language on the server and the client are the Javascript based way, in the Node ecosystem. Good designers or good front-end guys in general will also have coding skills, some will be Javascript gurus, but by doing things this way and writing Javascript code in Parenscript/Clojure script you'll have to force them to learn Lisp in order to work at 100%. And my bet is that they're not gonna like it, so team-wise, you'll lose all the productivity increase you gain in the first place by using Lisp. IF you can find a team of lispers that also have webdesign and frontend coding skills, great, but this will be fucking hard as far as I know it. I would just love working in such an environment, but it seems like a non-existent Nirvana right now...

pavelludiq 14y ago
There is a port of Googles closure-template system. It compiles closure templates to CL functions. They work pretty well. I have written about them in the book: http://lispwebtales.ppenev.com/chap04.html#closure-template http://lispwebtales.ppenev.com/chap04.html#closure-template It also compiles to js, so you can even share templates between the client and the backend. I'm experimenting with using both sexml and closure-template, but in the book I use almost exclusively sexml to make the code simpler. Also s-expressions are much easier to type in than sgml :)
juliangamble 14y ago
> but in the real world you'll want your HTML templates separate and in a designer or front-end-coder friendly format. For Clojure - it sounds like you're looking for Christophe Grand's work on enlive: https://github.com/cgrand/enlive https://github.com/cgrand/enlive You can read a tutorial here: https://github.com/swannodette/enlive-tutorial/ https://github.com/swannodette/enlive-tutorial/