add preview

lib/app-talks.js

@@ -1,7 +1,27 @@
 var fab = require("./fab")
   , app = require('./app')
+  , Slide = require('./slide').Slide
 
 with(fab) module.exports = (fab)
+  (route, /^\/preview/)
+    (function(write) {
+      return write(function(write, head, body) {
+        return fab.stream(function(stream) {
+          var text = ''
+          body(function(chunk) {
+            if(chunk)
+              text += chunk.toString('utf8')
+            else {
+              Slide.parse(text)(function(html) {
+                stream(write(html))
+                stream(write())
+              })
+            }
+          })
+        })
+      })
+    })
+  ()
   (route, /^\/([^\/]+)/) // :name
     (route, /^\/slides/)
       (app.static.html, 'slides')