can't use global with nesh

[freefrancisco]

I don't know if this is a problem with nesh, or user error, but when I start nesh with the option useGlobal: true (which is one of the options for repl) it doesn't work any more. Here is my test code:

 nesh = require 'nesh' 
opts = welcome: 'Howdy!', prompt: 'nesh> ', useGlobal: true
nesh.loadLanguage 'coffee'
nesh.start opts, (err) ->
  nesh.log.error err if err

And here is my output:

16:59 ~/code/play $ coffee neshtest.coffee
Howdy!
nesh> x=2
TypeError: needs a 'context' argument.
at REPLServer.replDefaults.eval (/usr/local/share/npm/lib/node_modules/coffee-script/lib/coffee-script/repl.js:33:28)
at repl.js:239:12
at Interface. (/usr/local/share/npm/lib/node_modules/coffee-script/lib/coffee-script/repl.js:62:9)
at Interface.EventEmitter.emit (events.js:117:20)
at Interface._onLine (readline.js:202:10)
at Interface._line (readline.js:531:8)
at Interface._ttyWrite (readline.js:754:14)
at ReadStream.onkeypress (readline.js:99:10)
at ReadStream.EventEmitter.emit (events.js:117:20)
at emitKey (readline.js:1089:12)
at ReadStream.onData (readline.js:834:14)
at ReadStream.EventEmitter.emit (events.js:95:17)
at ReadStream. (stream_readable.js:720:14)
at ReadStream.EventEmitter.emit (events.js:92:17)
at emitReadable (_stream_readable.js:392:10)
at emitReadable (_stream_readable.js:388:5)
at readableAddChunk (_stream_readable.js:150:9)
at ReadStream.Readable.push (_stream_readable.js:113:10)
at TTY.onread (net.js:511:21)

nesh>

What I am trying to do is run nesh with the same context as the main program so I can interact with the objects in node through nesh just like I would interact with ActiveRecord objects through the rails console. Is this possible? What am I doing wrong?

[danielgtaylor]

This definitely seems like it should work and I can confirm that it doesn't. I'm not sure why as the vm and repl modules are a bit of black magic. Here's a workaround that I would suggest until I can figure it out:

nesh = require 'nesh'

foo1 = 1
foo2 = 'something'
foo3 = new ...

nesh.loadLanguage 'coffee'
nesh.start prompt: 'nesh> ', (err, repl) ->
    if err then return nesh.log.error(err)

    repl.context.foo1 = foo1
    repl.context.foo2 = foo2
    repl.context.foo3 = foo3

This way you can expose objects and let users interact with them one by one. If you have a models module you can even expose it all in one go, e.g. repl.context.models = require('models'). Then a user can do stuff like nesh> user = new models.User(...) right in the interpreter. Alternatively you can loop through all the keys and expose each value one by one.

If you find yourself needing this often it would be relatively easy to write a plugin that does this during the postStart event.

Hope this helps.

[danielgtaylor]

I believe the changes proposed in #4 will fix this issue. They require upstream changes to work with Coffeescript though, so I don't have a timeframe for implementation. See #4 and jashkenas/coffeescript#3113 for more info.

[danielgtaylor]

It looks like this is fixed with CoffeeScript 1.7 - feel free to update (npm install -g coffee-script) and give it a try.

[freefrancisco]

It is fixed, yay! Thanks!

[danielgtaylor]

Closing as it's fixed with an upstream update.