#9: share scope

app/coffeescript_cell.coffee

@@ -5,6 +5,15 @@ Builtins = require './builtins'
 React = require 'react'
 Components = require './components'
 printStackTrace = require 'stacktrace-js'
+acorn = require 'acorn'
+escope = require 'escope'
+_ = require 'underscore'
+
+
+if process.browser
+  {Scope} = CoffeeScript.require './scope'
+  freeVariable = Scope::freeVariable
+  Scope::freeVariable = (name, reserve) -> freeVariable.call @, "LEAD_COFFEESCRIPT_FREE_VARIABLE_#{name}", reserve
 
 recompile = (error_marks, editor) ->
   m.clear() for m in error_marks
@@ -25,8 +34,13 @@ get_fn = (run_context) ->
 create_fn = (string) ->
   (ctx) ->
     try
-      compiled = CoffeeScript.compile(string, bare: true) + "\n//@ sourceURL=console-coffeescript.js"
-      return Context.scoped_eval ctx, compiled
+      locals = Object.keys ctx.repl_vars
+      compiled = CoffeeScript.compile(string, bare: true, locals: locals) + "\n//@ sourceURL=console-coffeescript.js"
+      ast = acorn.parse compiled
+      scopes = escope.analyze(ast).scopes
+      global_scope = _.find scopes, (s) -> s.type == 'global'
+      global_vars = _.pluck global_scope.variables, 'name'
+      return Context.scoped_eval ctx, compiled, _.reject global_vars, (name) -> name.indexOf('_LEAD_COFFEESCRIPT_FREE_VARIABLE_') == 0
     catch e
       if e instanceof SyntaxError
         Context.add_component ctx, Builtins.ErrorComponent message: "Syntax Error: #{e.message} at #{e.location.first_line + 1}:#{e.location.first_column + 1}"

app/context.coffee

@@ -170,7 +170,8 @@ TopLevelContextComponent = React.createClass
 # the base context contains the loaded modules, and the list of modules to import into every context
 create_base_context = ({module_names, imports}) ->
   modules = Modules.get_modules(_.union imports or [], module_names or [])
-  {modules, imports}
+  # TODO find a better home for repl vars
+  {modules, imports, repl_vars: {}}
 
 # the XXX context contains all the context functions and vars. basically, everything needed to support
 # an editor
@@ -298,13 +299,19 @@ create_standalone_context = ({imports, module_names}={}) ->
   base_context = create_base_context({imports: ['builtins'].concat(imports or []), module_names})
   create_run_context [create_context base_context]
 
-scoped_eval = (ctx, string) ->
+
+scoped_eval = (ctx, string, var_names=[]) ->
   if _.isFunction string
     string = "(#{string}).apply(this);"
-  context_scope = ctx.scope
-  `with (context_scope) {`
-  result = (-> eval string).call ctx
-  `}`
+  _.each var_names, (name) ->
+    ctx.repl_vars[name] ?= undefined
+  result = null
+  (->
+    `with (ctx.scope) { with (ctx.repl_vars) {`
+    result = eval string
+    `}}`
+  ).call ctx
+
   result
 
 eval_in_context = (run_context, string) ->

package.json

@@ -21,7 +21,9 @@
     "bacon.model": "0.1.10",
     "codemirror": "^4.3.0",
     "jsdom": "~0.8.4",
-    "react-router": "^0.5.0"
+    "react-router": "^0.5.0",
+    "acorn": "^0.6.0",
+    "escope": "^1.0.1"
   },
   "devDependencies": {
     "grunt": "~0.4.5",