How to clear a terminal in pyscript (py-terminal) - python

The idea is to clear the output of the python REPL provided by pyscript, embedded in a website.
I have tried the regular ways used in the OS console (os.system("clear"), print("\033c") and similar), but they don't work.
I have not found anything in the documentation of the py-repl or py-terminal elements.

A possible approach is to implement a function in python that uses the js module provided by pyscript to modify the DOM (see How to perform DOM manipulation using pyscript).
So a simplified version of my solution would look like this:
<py-script>
from js import document as _DOC
def clear():
ter = _DOC.getElementById("my-terminal")
ter.innerHTML = ''
</py-script>
Put this code before your REPL and now you can execute the clear() function from it and the terminal will be cleared.

Related

Using Jenkins variables/parameters in Python Script with os.path.join

I'm trying to learn how to use variables from Jenkins in Python scripts. I've already learned that I need to call the variables, but I'm not sure how to implement them in the case of using os.path.join().
I'm not a developer; I'm a technical writer. This code was written by somebody else. I'm just trying to adapt the Jenkins scripts so they are parameterized so we don't have to modify the Python scripts for every release.
I'm using inline Jenkins python scripts inside a Jenkins job. The Jenkins string parameters are "BranchID" and "BranchIDShort". I've looked through many questions that talk about how you have to establish the variables in the Python script, but with the case of os.path.join(),I'm not sure what to do.
Here is the original code. I added the part where we establish the variables from the Jenkins parameters, but I don't know how to use them in the os.path.join() function.
# Delete previous builds.
import os
import shutil
BranchID = os.getenv("BranchID")
BranchIDshort = os.getenv("BranchIDshort")
print "Delete any output from a previous build."
if os.path.exists(os.path.join("C:\\Doc192CS", "Output")):
shutil.rmtree(os.path.join("C:\\Doc192CS", "Output"))
I expect output like: c:\Doc192CS\Output
I am afraid that if I do the following code:
if os.path.exists(os.path.join("C:\\Doc",BranchIDshort,"CS", "Output")):
shutil.rmtree(os.path.join("C:\\Doc",BranchIDshort,"CS", "Output"))
I'll get: c:\Doc\192\CS\Output.
Is there a way to use the BranchIDshort variable in this context to get the output c:\Doc192CS\Output?
User #Adonis gave the correct solution as a comment. Here is what he said:
Indeed you're right. What you would want to do is rather:
os.path.exists(os.path.join("C:\\","Doc{}CS".format(BranchIDshort),"Output"))
(in short use a format string for the 2nd argument)
So the complete corrected code is:
import os
import shutil
BranchID = os.getenv("BranchID")
BranchIDshort = os.getenv("BranchIDshort")
print "Delete any output from a previous build."
if os.path.exists(os.path.join("C:\\Doc{}CS".format(BranchIDshort), "Output")):
shutil.rmtree(os.path.join("C:\\Doc{}CS".format(BranchIDshort), "Output"))
Thank you, #Adonis!

Ignore the rest of the python file

My python scripts often contain "executable code" (functions, classes, &c) in the first part of the file and "test code" (interactive experiments) at the end.
I want python, py_compile, pylint &c to completely ignore the experimental stuff at the end.
I am looking for something like #if 0 for cpp.
How can this be done?
Here are some ideas and the reasons they are bad:
sys.exit(0): works for python but not py_compile and pylint
put all experimental code under def test():: I can no longer copy/paste the code into a python REPL because it has non-trivial indent
put all experimental code between lines with """: emacs no longer indents and fontifies the code properly
comment and uncomment the code all the time: I am too lazy (yes, this is a single key press, but I have to remember to do that!)
put the test code into a separate file: I want to keep the related stuff together
PS. My IDE is Emacs and my python interpreter is pyspark.
Use ipython rather than python for your REPL It has better code completion and introspection and when you paste indented code it can automatically "de-indent" the pasted code.
Thus you can put your experimental code in a test function and then paste in parts without worrying and having to de-indent your code.
If you are pasting large blocks that can be considered individual blocks then you will need to use the %paste or %cpaste magics.
eg.
for i in range(3):
i *= 2
# with the following the blank line this is a complete block
print(i)
With a normal paste:
In [1]: for i in range(3):
...: i *= 2
...:
In [2]: print(i)
4
Using %paste
In [3]: %paste
for i in range(10):
i *= 2
print(i)
## -- End pasted text --
0
2
4
In [4]:
PySpark and IPython
It is also possible to launch PySpark in IPython, the enhanced Python interpreter. PySpark works with IPython 1.0.0 and later. To use IPython, set the IPYTHON variable to 1 when running bin/pyspark:1
$ IPYTHON=1 ./bin/pyspark
Unfortunately, there is no widely (or any) standard describing what you are talking about, so getting a bunch of python specific things to work like this will be difficult.
However, you could wrap these commands in such a way that they only read until a signifier. For example (assuming you are on a unix system):
cat $file | sed '/exit(0)/q' |sed '/exit(0)/d'
The command will read until 'exit(0)' is found. You could pipe this into your checkers, or create a temp file that your checkers read. You could create wrapper executable files on your path that may work with your editors.
Windows may be able to use a similar technique.
I might advise a different approach. Separate files might be best. You might explore iPython notebooks as a possible solution, but I'm not sure exactly what your use case is.
Follow something like option 2.
I usually put experimental code in a main method.
def main ():
*experimental code goes here *
Then if you want to execute the experimental code just call the main.
main()
With python-mode.el mark arbitrary chunks as section - for example via py-sectionize-region.
Than call py-execute-section.
Updated after comment:
python-mode.el is delivered by melpa.
M-x list-packages RET
Look for python-mode - the built-in python.el provides 'python, while python-mode.el provides 'python-mode.
Developement just moved hereto: https://gitlab.com/python-mode-devs/python-mode
I think the standard ('Pythonic') way to deal with this is to do it like so:
class MyClass(object):
...
def my_function():
...
if __name__ == '__main__':
# testing code here
Edit after your comment
I don't think what you want is possible using a plain Python interpreter. You could have a look at the IEP Python editor (website, bitbucket): it supports something like Matlab's cell mode, where a cell can be defined with a double comment character (##):
## main code
class MyClass(object):
...
def my_function():
...
## testing code
do_some_testing_please()
All code from a ##-beginning line until either the next such line or end-of-file constitutes a single cell.
Whenever the cursor is within a particular cell and you strike some hotkey (default Ctrl+Enter), the code within that cell is executed in the currently running interpreter. An additional feature of IEP is that selected code can be executed with F9; a pretty standard feature but the nice thing here is that IEP will smartly deal with whitespace, so just selecting and pasting stuff from inside a method will automatically work.
I suggest you use a proper version control system to keep the "real" and the "experimental" parts separated.
For example, using Git, you could only include the real code without the experimental parts in your commits (using add -p), and then temporarily stash the experimental parts for running your various tools.
You could also keep the experimental parts in their own branch which you then rebase on top of the non-experimental parts when you need them.
Another possibility is to put tests as doctests into the docstrings of your code, which admittedly is only practical for simpler cases.
This way, they are only treated as executable code by the doctest module, but as comments otherwise.

Calling Python code from Gnome Shell extension

I was looking for some time, but still can't find any documented way to call python functions from GnomeShell extension code. Is there any possibility to do that?
You can do it like this :)
const Util = imports.misc.util;
let python_script = '/path/to/python/script';
Util.spawnCommandLine("python " + python_script);
I don't know how to directly call a python function from Gnomeshell, but there is an alternative way. As gnomeshell is programmed with Javascript you could use a python to javascript compiler to translate the python functions you need.

Python WebKitWebView: how to get (generated) source code

Is it possible to get the generated source code (so including JavaScript added DOM nodes) with Python and WebKit, and if so, how?
import webkit
web_view = webkit.WebView()
web_view.open('http://google.com')
But then?
Bind a function to the loadFinished(bool) signal, in that function you can use mainFrame().toHtml() to get the source code.
I found how to do it here: http://blog.motane.lu/2009/06/18/pywebkitgtk-execute-javascript-from-python/

How do you listen to notifications from iTunes on a Mac (Using the NSDistributedNotificationCenter)

Looking for help/tutorials/sample code of using python to listen to distributed notifications from applications on a mac. I know the py-objc lib is the bridge between python and mac/cocoa classes, and the Foundation library can be used to add observers, but looking for examples or tutorials on how to use this to monitor iTunes.
If anyone comes by to this question, i figured out how to listen, the code below works. However accessing attributes do not seem to work like standard python attribute access.
Update: you do not access attributes as you would in python i.e (.x), the code has been updated below, it now generates a dict called song_details.
Update3: Update to the code, now subclassing NSObject, removed adding the addObserver from the class. Will keep the code updated on github, no more updates here.
import Foundation
from AppKit import *
from PyObjCTools import AppHelper
class GetSongs(NSObject):
def getMySongs_(self, song):
song_details = {}
ui = song.userInfo()
for x in ui:
song_details[x] = ui.objectForKey_(x)
print song_details
nc = Foundation.NSDistributedNotificationCenter.defaultCenter()
GetSongs = GetSongs.new()
nc.addObserver_selector_name_object_(GetSongs, 'getMySongs:', 'com.apple.iTunes.playerInfo',None)
NSLog("Listening for new tunes....")
AppHelper.runConsoleEventLoop()
The source code for GrowlTunes might give you some clues here. You'd have to translate from Objective-C to PyObjC, but eh, whatever. :)
GrowlTurnesController.m
(Or grab the whole growl source tree and navigate to GrowlTunes so you can see it all in action.: here's a link to the directions on how to get the source

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