REPL breaks on some errors

[raine]

Some errors break a REPL session in such way that it can't be used anymore, arrow keys for browsing history break etc.

This is on 1.4 from npm

$ lsc -d
LiveScript 1.4.0 - use 'lsc --help' for more information
ls> map 1, null

/usr/local/lib/node_modules/livescript/node_modules/prelude-ls/lib/List.js:13
  for (i$ = 0, len$ = xs.length; i$ < len$; ++i$) {
                        ^
[TypeError: Cannot read property 'length' of null]
ls>


...

undefined
ls> ^[[A^[[A^[[A^[[A^[[A

[raine]

I had a look at this and can't figure it out.

The exception happens here https://github.com/gkz/LiveScript/blob/master/src/command.ls#L314 and is caught below but it screws up the repl somehow.

A peculiar thing I noticed is that if you ^D after getting an exception with throw \foo, the uncaughtException handler triggers with

TypeError: Cannot read property 'setRawMode' of null
    at ReadStream.setRawMode (tty.js:67:15)
    at Interface._setRawMode (readline.js:177:23)
    at Interface.close (readline.js:286:10)
    at ReadStream.ontermend (readline.js:105:10)
    at ReadStream.emit (events.js:129:20)
    at _stream_readable.js:908:16
    at process._tickDomainCallback (node.js:381:11)

Why is it that throw \foo breaks the repl but this doesn't?

ls> test
[ReferenceError: repl:2
test is not defined]