Like a total newbie I put the call to the interpreter in the view
function instead of the update function! I thought it was weird having
to specify the HTML twice, but I figured I was just doing it wrong. I
was, but not in the way I suspected.
In any event, I like how this make it clear that errors can't affect the
dictionary.
This is mostly for fun, but I bet it comes in handy, eh?
At the very least, it's a nice catalog of the possible errors that the
basic Joy system might encounter.
Just sqr for now, but it shows that it works.
I would like to return Results from add_def but it makes using foldl
slightly tricky, not a lot, just slightly, and my brainpower is low at
the mo'.
I don't like passing the stack through isnt_int but that let's you chain
with andThen.
There's probably a clever or idiomatic way to not do that and couple the
stack to the result without passing it through the type checker function
but I don't know what it is right now, and this works.
sforman