JavaScript namespace

One thing I like about Python, is that it has namespaces and variables don’t just come out of nowhere.

Here is example:

__pragma__('alias', 'jQuery', '$')

def start():
    def changeColors(divs):
        for div in divs:
            rgb = [int(256 * Math.random()) for i in range(3)]
            jQuery(div).css({'color': 'rgb({},{},{})'.format(*rgb)})

    changeColors(jQuery('div'))
    window.setInterval(changeColors, 500)

This code has 4 undefined variables, that comes out of nowhere. All Python static syntax checkers will issue number of errors, for example:

> pyflakes jquery.py
jquery.py:1: undefined name '__pragma__'
jquery.py:6: undefined name 'Math'
jquery.py:7: undefined name 'jQuery'
jquery.py:9: undefined name 'jQuery'
jquery.py:10: undefined name 'window'

Having a namespace that represents JavaScript global namespace would solve this issue, for example:

import __transcrypt__
import __javascript__ as js

__transcrypt__.alias('jQuery', '$')

def start():
    def changeColors(divs):
        for div in divs:
            rgb = [int(256 * js.Math.random()) for i in range(3)]
            js.jQuery(div).css({'color': 'rgb({},{},{})'.format(*rgb)})

    changeColors(js.jQuery('div'))
    js.window.setInterval(changeColors, 500)

Now, there is no undefined variables and it is clear what comes from JavaScript or Transcrypt and what is defined in Python modules.

[JdeH]

I like the elegance of your idea but, after a realy hard try, haven’t succeeded in coming up with a good implementation. As for satisfying the static checker (pyflakes, part of the distro, activated with -c switch), you can use:

 __pragma__ ('skip')
window = Math = Date = 0    # Prevent complaints by optional static checker
__pragma__ ('noskip')

[JdeH]

Nice trick, thanks.