I apologize in advance, because I know the answer will be simple (but I couldn't find an example and have tried all sorts of options).

I am trying to run xquery:eval passing in a string to evaluate and a map of bindings.  Everything I try I get an 'Undefined variable' error.

Here is a simple example I tried in the BaseX Gui. 

let $a := 3

let $string := "$a + 1"

return

xquery:eval($string, map{"a" : $a}

This is just one attempt, but there were many others.

Again, I know this is going to be a simple mistake I'm making, so apologies to the community in advance.

Thanks,

Buddy