Re: [Chicken-users] A call to arms

[Tobia Conforto]

Ok, since you asked for it... here are some random thoughts on an  
"ideal web application framework"


- No database/SQL (except where truly needed) just plain S-expr file  
storage

Using Git as a filesystem is clearly the best solution.  I would use  
it with s-expr files though, not XML (ugh!) as XML and HTML data can  
always be represented with sxml if need be.

Databases can be left to their true purpose (dealing with a million  
customer records, orders, products, invoices, forum posts...) while  
everything else is stored in plain, versioned, s-expr files.


- Multi-tiered, component-based architecture

This is a good start:

> Presuming that some hidden machinery has arranged a chain of  
> generators by matching the incoming url, it would call a generator,  
> e.g.
>
> (lambda (next)
>  (html (div (h1 "some headline)
>             (next) ; <<
>        )))


But I would make it more powerful.  See for example sxml's pre-post- 
order transformer, where you can express arbitrary pre-order and post- 
order transformations.  That is, having the option to capture the  
output of your (next) and process it further.

Better still, we could come up with a Scheme equivalent of Apache  
Cocoon's pipelines, where you define regexp matchers on incoming URLs  
and assign 'pipelines' to them.  A Cocoon pipeline is a chain that  
starts with one or more 'generators' (a component that generates a  
flow of data in a common, abstract format), passing through zero or  
more 'transformers' (components that alter the data flow in arbitrary  
ways) and ending in a 'serializer'.  Cocoon uses the SAX API as the  
abstract data format, but we of course could use the List.

This is promising, I need to think more about it.


- Fast development turnaround time

Having the framework split into basic plumbing and a collection of  
components, would mean that we could have the plumbing compiled  
separately from the components, and we could keep some components  
compiled and others interpreted (instant turnaround time) while we are  
working on them.

Newbie question: can Chicken load and (more importantly) unload/reload  
a .so at runtime? I've never tried to.


-Tobia