add history file support to repl.js

repl.js

@@ -1,3 +1,43 @@
 #!/usr/bin/env node
 
-require('./lib/index').startRepl()
+var fs = require('fs')
+  , path = require('path')
+  , repl = require('./lib/index').startRepl()
+  , DefaultHistoryFile = path.join(process.env.HOME, '.node_history')
+  , historyFile
+
+if ('NODE_HISTORY' in process.env)
+  historyFile = process.env.NODE_HISTORY
+else
+  historyFile = DefaultHistoryFile
+
+// restore history immediately
+if (historyFile) {
+  try {
+    fs.statSync(historyFile)
+    var json = fs.readFileSync(historyFile)
+    repl.rli.history = JSON.parse(json)
+  }
+  catch (e) {
+    if (e.code !== 'ENOENT') {
+      console.error('!!! Error reading history from ' + historyFile)
+      if (e.message === 'Unexpected token ILLEGAL') {
+        console.error('is this a JSON array of strings? -> ' + json)
+      }
+      else {
+        console.error(e.message)
+      }
+    }
+  }
+
+  // save history on exit
+  process.on('exit', function() {
+    try {
+      fs.writeFileSync(historyFile, JSON.stringify(repl.rli.history))
+    }
+    catch (e) {
+      console.error('Error writing history file to ' + historyFile)
+      console.error(e)
+    }
+  })
+}