Introducing PyScript (summary of PyCon keynote)
The article describes what is possible with Python in a browser, but misses an important detail: how much memory it consumes and how much CPU it uses.<p>Python is not a fast language. For example, consider a simple loop:<p><pre><code>    for i in range(10):
        pass
</code></pre>
In Python, this will be compiled into: a call to range(), heap allocation of an Iterable, calling getIterator() on an Iterable (which might also do allocation), calling next() on an Iterator while catching for StopIteration exception (and calls are often slow in interpreted languages). While in C we could just have a loop without any calls.<p>I remember how I had to use a Dart-based web application (compiled to JS) in one of Google's advertising products. The script weighed around several megabytes and everything was so slow. Furthermore, there also was a small and useless "what's new" applet, and it probably was shipped with a separate copy of Dart runtime because it weighed several megabytes too. Obviously this was a product intended to be used only on latest MacBooks, not on a Windows XP laptop.<p>It is totally fine to write such application for youself, or maybe for internal use, but if you are a corporation with millions of users, I think you should pay a little attention to performance and choose a better technology. Or, if you are of a Google scale, find a way to optimize the code.