Here's a function that always returns true - but it could do any kind of data access. It is just plain Clojure.
(defn selected? [] true)
Here is a datastructure that represents html: [:h2 {:class (when (selected?) "selected")} "Hello"]
Calling the function hiccup.core/html on that datastructure yeilds an html string like this: "<h2 class='selected'>Hello</h2>"
So that's great for _strings_ right? But there is an awesome library for ClojureScript called Reagent. And it uses those simple datastructures to generate react components!! I put some more examples at: http://hiccup.spaceThe ability to copy snippets of HTML from web, or old code when refactoring, or from Clojure/Hiccup to another language & framework, or changes from developer tool, or familiarity for new engineers, or not having to care about what flavor of HTML is hip today is a huge productivity boost for me.
I would love to see push for template strings [1] in Clojure, it should be trivial with macros. It would only take some time for IDEs to catch up. They're good. So good they've even influenced Python 3 to add them.
(defui my-component [x]
"<h2 class=(when (selected? x) ["selected"])>Hello</h2>")
[1] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Refe... (defui my-component [x]
<h2 class=(when (selected? x) ["selected"])>Hello</h2>)
It's possible to macro the above to the code below, without any language extensions. IntelliJ has powerful nested DSL introspection, it would be neat if Cursive allowed to hook into this through defui's metadata for highlighting. I was a hater of JSX until I used it. Now I hate eDSLs. :D (defn my-component [x]
[:h2 {:class (when (selected? x) ["selected"])} "Hello"])It helps that Clojure's syntax is based on s-expressions, and s-expressions are already isomorphic to HTML/XML.
So in a way, you're still mixing your templates and your code, but you happen to be using the same syntax for both. Which is arguably an improvement.
The equivalent would be something like
function() selected { return true }
["h2", {class: function() {if (selected()) {return "selected"}}}, "Hello"]
Not as clean, but still usable IMOThe worst I've seen is a bit of confusion between models and controllers. But views are usually as clean as the Gods of MVC commanded.
Not a good thing, IMO, since it makes the syntax way more complicated, but there you have it.
then they wrote template languages on top of the template language to separate layout and logic again ( PHP vs Twig/Smarty )
so maybe we need to step back a little and figure out how to write a language that wouldn't need a different syntax for logic and layout. This family of languages exists already, but since current developers grew up with C like languages, it is not that popular.
IMHO the best compromise is direct support for XML syntax inside languages (which Javascript had at some point with E4X) because I don't think anyone will be able to make developers use LISP like languages on a wide scale. JSX, with some modifications and standardisation could also be a solution.