Let's see how it looks like:
With easy you use the # marker for HTML IDs, e.g. #vala, used here for input box. Reading the value using
is easy like writing it back to another HTML element identified by ID
Give it a try:
$ opa easycalc.opa $ ./easycalc
Then point Chrome (or your favourite browser) to http://localhost:8080/. Opa compiler will take care of everything!