module javascript
imports libstrategolib signatures/- util

signature
  constructors
    TopLevel: Ex -> Ex

rules
  js: TopLevel(x) -> $[const Stdio = {
    gets: v => { process.stdout.write(String(v)); return Stdio; },
  }
  function to(data, strm) {
    strm.gets(data);
    return data;
  }
  [x]]

  js: Stream() -> $[Stdio]
  js: Int(x) -> x
  js: Sum(x,y) -> $[[x] + [y]]
  js: Gets(x, y) -> $[[x].gets([y])]
  js: To(x, y) -> $[to([x],[y])]
  js: Sequence(l) -> <join(|";\n")>l

strategies

  javascript = bottomup(try(js))

  // Interface javascript code generation with editor services and file system
  to-javascript: (selected, _, _, path, project-path) -> (filename, result)
    with filename := <guarantee-extension(|"js")> path
       ; result   := <javascript> selected