PythonScript early return

Paul Wormer

Usually my scripts start with checks on applicability etc. If certain conditions do not hold or errors are detected the script writes an error msg and takes an early return. I searched for a way to return from a PythonScript - other than at the bottom - but couldn’t find it. Is there a way to return from a PythonScript?

Alan Kilborn

@paul-wormer

Perhaps the simplest illustration of how to do it:

def main():
    # do some stuff
    x = 0
    if x == 0: return  # take an early exit
    # do more stuff

main()

Alan Kilborn

Or you can take the class-based approach to script design, which I prefer. Here’s my template for that:

# -*- coding: utf-8 -*-
from __future__ import print_function

from Npp import *
import inspect
import os

#-------------------------------------------------------------------------------

class TEST(object):

    def __init__(self):
        self.this_script_name = inspect.getframeinfo(inspect.currentframe()).filename.split(os.sep)[-1].rsplit('.', 1)[0]

    def run(self):
        self.mb('Hello from TEST !')

    def mb(self, msg, flags=0, title=''):  # a message-box function
        return notepad.messageBox(msg, title if title else self.this_script_name, flags)

#-------------------------------------------------------------------------------

if __name__ == '__main__':
    TEST().run()

In this approach you can return early from any function, just like the non-class-based example from the previous post.

–
moderator edit: added import os to make it work for default setups (since this script is being referenced by other posts, Alan wanted this to be a “working” script for future user’s copy/paste, and the moderator agreed)

Paul Wormer

@alan-kilborn
Yes this solution is very simple, I should have thought of it 😉.

Paul Wormer

@alan-kilborn

inspect.getframeinfo(inspect.currentframe()).filename.split(os.sep)[-1].rsplit('.', 1)[0]

This is abracadabra to me. To begin with, where can I find the attributes of the inspect class?

Paul Wormer

@paul-wormer Stupid question: I see that ‘inspect’ is a Python module.

Alan Kilborn

@paul-wormer

I should have added that the “inspect” stuff is there because when I write scripts that use either notepad.messageBox() or notepad.prompt() functions, these bring up a dialog box, and take a parameter to specify the title bar; I like to put the script name there (typically), and rather than hardcode its name, I fetch it at runtime using “inspect”. My mb() function is a little helper function that “wraps” notepad.messageBox() and shows this.

Paul Wormer

@alan-kilborn OK thank you, you give me something to try out!

Paul Wormer

@paul-wormer I see “os.sep”, shouldn’t one “import os”?

Alan Kilborn

@paul-wormer said in PythonScript early return:

I see “os.sep”, shouldn’t one “import os”?

Yes, good catch.

So the reason it doesn’t fail without it, for me, is that my startup.py (or something it imports) must import os.

I usually test all of my scripts in a “clean” setup before posting; this one seemed so simple, I guess I didn’t bother. :-(

PythonScripts are a bit different from the normal use case for Python – here, everything previously done is “remembered”.

Paul Wormer

@paul-wormer
So,

import inspect, os 
inspect.getframeinfo(inspect.currentframe()).filename.split(os.sep)[-1].rsplit('.', 1)[0]

is wizardry just to get the script name without extension?

Alan Kilborn

@paul-wormer said in PythonScript early return:

is wizardry

???

No wizardry, just code.

Paul Wormer

@alan-kilborn Just kidding. OK you helped me a lot, got wiser by the minute. I know now what to do, thank you again.

Paul Wormer

@paul-wormer
Next question: I have been googling and found an alternative for finding a filename:

os.path.basename(os.path.abspath(__file__)).rsplit('.')[0]

This does not require importing inspect. I don’t doubt that you are aware of this solution, and since you are not using it, it must have its drawbacks. What are they?

Paul Wormer

@paul-wormer Or even shorter:

os.path.basename(__file__).rsplit('.')[0]

Alan Kilborn

@paul-wormer

So, often when I post scripts here, I take something existing that I have (working for a need specific to me), and strip some things out. That’s the case here.

As we’re really trying to focus on Notepad++ and/or PythonScript specific stuff here, diving deeper into the ways of “inspect” or other such things really isn’t appropriate, as it is really not related to either.

In the spirit of fun coding, if you find what you think is a better way of doing something, I say “go for it!”.

Alan Kilborn

@paul-wormer said in PythonScript early return:

I see “os.sep”, shouldn’t one “import os”?

I requested a forum moderator to add the missing import os to the script listing above, and that was done…thanks Mr. Moderator!