[Ur] More questions: sql_injectable, reactivity and interaction with CSS

[Artyom Shalkhakov]

Hello,

There are more questions I'd like to ask.

First, Is there any way to write an sql_injectable instance? I'd like
to serialize and deserialize a tree data structure (xbody in
particular) to store it in the database.

Second, I don't quite get the "reactivity" of Ur/Web. For example, in
Flapjax, you use events (discrete occurrences of values in time) and
behaviors (contrary to events, these are continous), and then
"connect" all this to the outside world by a couple of side-effecting
functions.

In Ur OTOH, there are "sources" (which, IIUC, implement the concept of
a "store": that is, they are "variables" as in imperative languages),
and there are "signals", which are pure functions over sources (in the
"signal" monad). So is Ur "reactive" in the sense that modification of
sources is automatically propagated to every dependent dyn tag?

I'm trying to write a simple in-place editor for text. Given some text
on a webpage, users can double-click on a paragraph, say, which turns
the text into a text box and two buttons (apply and cancel). I don't
know how to do this.

Third, what is the approach to styling elements? ATM, the only way to
communicate with CSS is via classes, but is full CSS embedding worth
it?

And finally, can you compare Ur to OPA of <www.mlstate.com>?

Cheers,
Artyom Shalkhakov.