Re: sfx: baby steps of an html templating engine based on skribillo's skribe reader and sxml

[Nala Ginrut]

IMO, skribillo is for static pages, and Artanis is largely for dynamic
pages. After quick review of your code, it seems what you want is to
redefine SXML:

(link (@ :rel "stylesheet" :href "static/css/bootstrap.min.css"))

It looks cleaner than SXML, but if you want to define a syntax, it's
better have a formal grammar definition, say, BNF or something similar.

Best regards.

On Thu, 2015-07-30 at 13:55 +0200, Amirouche Boubekki wrote:
> Héllo,
> 
> 
> I've been lurking around skribillo and artanis. I don't really like the 
> rails-like syntax
> of artanis, even if it has its use-cases and I wanted to hack on 
> something "small", so
> I've put together sfx.
> 
> The code of skribe reader is included in sfx.scm. So the only dependency 
> is guile (2.0.11) and
> guile-reader that you can install using `guix package -i guile-reader`.
> 
> This bare template language has the following features:
> 
> - wanna be simpler sxml syntax
> - templates with custom environment
> - external libraries loading inside the template
> 
> 
> # Wanna be simpler sxml syntax
> 
> Skribe reader (implemented with guile-reader) provide a handy syntax to
> both define keywords and quasiquote. In an sxml context those features
> are used to implemented attributes and text nodes.
> 
> ## attributes
> 
> Attributes in sxml are defined as follow:
> 
>    (div (@ (id "shell")) "This the main area")
> 
> Instead of requiring the nesting of `(attribute-name attribute-value)` 
> sfx use
> the simpler keyword syntax `:keyword`. The above snippet becomes:
> 
>    (div (@ :id "shell") "This the main area")
> 
> I'm not sure it's worth the trouble of diverting from sxml standard. 
> That said, it looks
> more like plain xml.
> 
> ## text nodes
> 
> Text nodes can be defined as
> 
>    (p [héllo hacker])
> 
> This is looks the same as the default reader. It becomes handy when you 
> include an
> inline element inside the text node:
> 
>    (p [héllo ,(b [hacker])
> 
> `,()` is a special syntax of skribe reader which provides `(unquote)` 
> inside [bracket] `quasiquote`.
> 
> With the default guile reader, this must be written as:
> 
>    (p "héllo " (b "hacker"))
> 
> This is looks verbose and prone to error. One must not forget the space 
> in the
> string before the `(b)` element.
> 
> 
> # templates with custom environment
> 
> Right now this part of the template language is not really userfriendly. 
> But you can pass custom
> variables to the template but those must be parameters. In the example 
> sfx.scm (which includes
> example use of the procedures) the environment in which the template is 
> evaled is defined as follow:
> 
>    (define value (make-parameter 42))
>    (define amirouche (make-person "amirouche" 30))
>    (define env (let ((value value)
>                      (amirouche amirouche))
>                  (the-environment)))
> 
> 
> Then `value` can be echo'ed inside the template using the unquote syntax 
> `,()`, e.g.
> 
>     (p [Here is a lucky number for you «,(value)»])
> 
> As you can see the previous snippet, there is also a `<record>` record 
> inside the environment.
> One can (maybe) provide in the environment the required procedures to 
> echo the correct
> fields but this is verbose. Instead sfx use `(use-modules)` inside the 
> template definition
> file. This is presented in the following and last part.
> 
> # external libraries loading inside the template
> 
> Currently it's (only) possible to do `(use-modules)` inside the template 
> file. The template
> file looks like the following:
> 
> ```
> (use-modules (person))
> 
> `(html
>    (body
>      (p [My name is ,(person-name amirouche)])))
> ```
> 
> I could not make procedure definition work inside the template, this my 
> be linked to the way
> I eval the template. It's shame because for quick and dirty hacks it can 
> be handy like defining
> mini-templates inside the big template.
> 
> 
> 
> 
> 
> This is my second try at this and having a look at the code of haunt [1] 
> was helpful.
> 
> Hope this helps!
> 
> 
> [1] https://git.dthompson.us/haunt.git
> 
> 
>