This is my code from lisp webtales and the result of the approximately four days it took me to study the book and build the application described in it. I had to fix a few problems with the code in the book. What these were and how I resolved them is noted in the commit messages.
My best guess as to why the code in the book didn't work for me as written is that perhaps the restas source has changed a bit since the book was published.
My Lisp adventures have as ever been greatly inspired and helped by the wonderful CL folks on stackoverflow with special thanks to Rainer Joswig, Renzo & coredump. It's always an inspiration that such experienced and knowledgeable folks give their time and expertise so freely to the interested learner.
Having completed more or less all of Paul Graham's book ANSI Common Lisp, I needed to find ways to get more practice. Since I have close familiarity with the problem web applications solve from my day to day work in other languages, seeing how these same problems are conquered in LISP seemed like a good plan.
- The common languages used for web programming all seem to create a bunch of DSLs which we must navigate and which are not compatible with one another. The most obvious perhaps are those for templating and validation. (My point is that those are different from the core language, i.e. they are different from that syntactically, and from each other). Personally I only really became aware of this from the perspective of lisp. Then I started to think about its impact. It's pretty big.
- Lisp tends to not do that and it's only when you've seen that it's possible do you realise what barriers those other systems actually erect to your thinking. You are no longer forced to use multiple incompatible languages.
- To take a different example, the framework here, Restas, uses generic functions to achieve what in OO is called Inversion of control. It does it with virtually no ceremony which I don't think could be said of OO code. Reason is the powerful constructs in the language. In this case, generic functions.
- Freer organisation. MVC is just one option. Because of the lack of DSL's as mentioned, you're much freer to code in a way that suits the task at hand in minimalistic manner. Minimalism in code is greatly underestimated. Smaller programs are easier to change and maintain. That means you are immediately more agile if you code minimalistically.
- Code is about 50% shorter for the same tasks.
- Easier to understand (once you've learnt Lisp, of course).
I used CCL for this, as asdf is
needed and CLisp which I'd been using has an older version of asdf which
I didn't bother trying to upgrade. Quicklisp must be installed,
and this repo should be placed in your local-projects directory of Quicklisp.
The final commit demonstrates extracting a restas module, whereby the auth system becomes a
separate package. Therefore to run that, you need this additional
repo in your local-projects directory, which is the extracted auth system as a module.
If you don't care about having the auth system as a separate module to start with, (a good idea when
looking at the code for the first time), then check out an earlier commit of this repo, then you won't
need the aforementioned authdemo at all, as in those earlier commits, that code is still in the main
app.