Add a few missing math blocks

[CelticMinstrel]

Just roots, logs, and signum, basically.

[dethe]

There's a parse error in runtime.js which is causing tests to fail.

[CelticMinstrel]

By the way, is there a way for the log block to reference the existing e constant rather than duplicating it?

[dethe]

I don't see why not.

[CelticMinstrel]

I don't know how to do that...

[dethe]

Looks good. :shipit:

[CelticMinstrel]

It would be nice if I could do something like this:

<wb-expression ns="math" type="number" fn="log">
    <wb-value type="number" value="1">logarithm of</wb-value>
    <wb-value type="number">to base
        <wb-expression ref="e"></wb-expression>
    </wb-value>
</wb-expression>

(That's hypothetical syntax based on XML schemas.)

[dethe]

Oh, I see what you mean. It's going a little bit the other way because I'm a) trying to make expressions reactive and b) keeping things consistent so we don't have too many different patterns for doing things. I'll look for ways to avoid duplication or automate the generation of the necessary functions.

[CelticMinstrel]

I'm guessing that means there's no way to do that at the moment?