Support repl multiline input

[hayd]

This works, but I had to comment out the setTimeout test, maybe due to #1161.

Note: It's not interactive over multiple lines (only the last line is editable).

[ry]

LGTM - I suspect we'll have to go through several revisions of this.

[kevinkassimo]

Yeah we definitely need to improve this later. This solution currently has problems like

> var a = "{";

it won't check if { is in quotes and would instead treat as if user is in a block...

Maybe we could for now differentiate Shift + Return and Return and use the previous to enable multiline input?

[ry]

I would just have a look at how node does this...

[kevinkassimo]

@hayd Actually your intuition is correct. Node does the following:
https://github.com/nodejs/node/blob/8344f2458111904ad1de4ce08ffd9b4360ce81ed/lib/repl.js#L655-L668

// If error was SyntaxError and not JSON.parse error
      if (e) {
        if (e instanceof Recoverable && !sawCtrlD) {
          // Start buffering data like that:
          // {
          // ...  x: 1
          // ... }
          self[kBufferedCommandSymbol] += cmd + '\n';
          self.displayPrompt();
          return;
        } else {
          self._domain.emit('error', e.err || e);
        }
      }

Also we might want to implement something similar to Node's vm that relies on binding to V8 context to make let/const work.

Should we implement stuff like vm at current stage?

[hayd]

I think we can wait on some compiler improvements (to compile ts) by @kitsonk @bartlomieju , once that is in, it could be refactored to include vm... I'm not sure it makes sense to define until then.

#1169