String escaping utility for Python (was: Rawest raw string literals)

[MRAB]

On 2017-04-22 23:30, Mikhail V wrote:
> On 20 April 2017 at 23:54, MRAB <python at mrabarnett.plus.com> wrote:
> > On 2017-04-20 22:03, Mikhail V wrote:
> >>
> >> On 20 April 2017 at 22:43, Random832 <random832 at fastmail.com> wrote:
> >>> [snip]
> >>>
> >>> The best solution I can think of is to have a text editor designed to
> >>> parse a string literal, spawn a nested editor with the unescaped
> >>> contents of that string literal, and then re-escape it back to place in
> >>> the code. If we had that, then we wouldn't even need raw strings.
> >>
> >>
> >> Yes exactly, it would be cool to have such a satellite app
> >> which can escape and unescape strings according to rules.
> >> And which can also convert unicode literals to their ascii
> >> analogues and back on the fly, this would very useful
> >> for programming.
> >> Probably it is a good idea to even include such thing
> >> in Python package. So it would be a small standalone app
> >> running parallel with text editor making it to copy paste strings.
> >>
> > I'm sure it's possible in, say, Emacs.
> >
> > The editor that I use (EditPad Pro) can call external tools, so I could:
> >
> > 1. Select the string literal (easy when it is syntax-aware, so I can select
> > all of the literal with 2 keypresses).
> >
> > 2. Call the external tool (1 keypress), to open, say, a simple tkinter app.
> >
> > 3. Edit the unescaped text (unescape with ast.literal_eval, re-escape with
> > 'ascii').
> >
> > 4. Close the external tool, and the selection is replaced.
>
> I have done a quick google search and could not find
> such utility for Python.
>
> I am very interested in having such utility.
> And I think it would be fair that such utility
> should be made by the Python team so that
> all syntax nuances will be correctly implemented.
>
> The purpose is simple: reduce manual work to escape special
> characters in string literals (and escape non-ASCII characters).
>
> Simple usage scenario:
> - I have a long command-line string in some text editor.
> - Copy this string and paste into the utility edit box
> - In the second edit box same string with escaped characters
>    appears (i.e tab becomes \t, etc)
> - Further, if I edit the text in the second edit box,
>    an unescaped string appears in the first box.
>
> Possible toggle options, e.g. :
> - 'asciify' non-ascii characters
>
> It could be not only useful to eliminate boilerplate typing,
> but also a great way to learn string rules for Python learners.
>
Here's a very simple tkinter GUI app. It only goes one way (plain to 
escaped (asciified)), but it shows what's possible with very little code.


#! python3.6
# -*- coding: utf-8 -*-
import tkinter as tk

class App(tk.Tk):
     def __init__(self):
         tk.Tk.__init__(self)
         self.title('Escaper')

         tk.Label(self, text='Plain string').pack()

         self.plain_box = tk.Text(self)
         self.plain_box.pack()
         self.plain_box.focus()

         tk.Label(self, text='Escaped string').pack()

         self.escaped_box = tk.Text(self)
         self.escaped_box.pack()

         self.after(100, self.on_tick)

     def on_tick(self):
         plain_string = self.plain_box.get('1.0', 'end')[ : -1]

         escaped_string = ascii(plain_string)

         self.escaped_box.delete('1.0', 'end')
         self.escaped_box.insert('1.0', escaped_string)

         self.after(100, self.on_tick)

App().mainloop()