Python.exe in Emacs26 for M$ Windows - REPL problem

Python.exe in Emacs26 for M$ Windows - REPL problem

[Eduardo Ochs]

Hello list,

big message, split in two parts.


1. Introduction
===============
I sometimes use Emacs and eev to present some principles of Free
Software - for example this, but in practice:
https://www.gnu.org/software/emacs/emacs-paper.html#SEC29 - to total
newbies, but I always have to tell them that the nicest feature of
eev, called "eepitch", currently doesn't work well on their Windows
machines...  it is explained here:

  http://angg.twu.net/eev-intros/find-eev-quick-intro.html#6
  http://angg.twu.net/eev-intros/find-eepitch-intro.html

and there's a demo of it here:

  https://www.youtube.com/watch?v=86yiRG8YJD0&t=956s

The problem is that downloading and installing Lua, Python, Bash or
MinGW/MSYS2 on Windows is non-trivial and people have very short
attention spans, so I sort of "don't have the time" to install any of
those things on their machines - I mean, before they lose focus.

Two days ago when I helped another newbie to install Emacs in her
machine from this .zip,

  http://gnu.c3sl.ufpr.br/ftp/emacs/windows/emacs-26/emacs-26.3-x86_64.zip

and I noticed that it comes with a python.exe, a tclsh.exe and a
wish.exe.  I didn't have time to test these .exes on her machine, and
I don't have access to a W$ box, but earlier today I asked for help in
the #emacs channel and a person there - Jeff Carlson - ran some sexps
for me in his W$ laptop.  His Emacs was installed using Chocolatey, so
his paths may be a bit atypical, but this

  (find-file "C:/ProgramData/chocolatey/lib/Emacs/tools/emacs/bin/")

opened the directory with python.exe, tclsh.exe, and wish.exe, and I
expected that this

  (switch-to-buffer
   (make-comint
    "python.exe"
    "C:/ProgramData/chocolatey/lib/Emacs/tools/emacs/bin/python.exe"))

would enter a Python REPL in comint... but no, we got these errors:

  Could not find platform independent libraries <prefix>
  Could not find platform dependent libraries <exec_prefix>
  Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]
  ImportError: No module named site

  Process python.exe exited abnormaly with code 1



2. Questions
============
1. Where can I find the rationale for why there are a python.exe, a
   tclsh.exe, and a wish.exe in Emacs26 for Windows?

2. This is the variable that points to their directory, right?

     (describe-variable 'exec-directory)

3. How are these .exes meant to be called?  What are the main
   functions and .el files that call them?  Is `exec-directory' a part
   of the default path in Windows?

4. Is (switch-to-buffer (make-comint ... ...)) supposed to work with
   them?  Can someone test that with python.exe, tclsh.exe, and
   wish.exe and check that we get working REPLs?



Many, many thanks in advance =),
  Eduardo Ochs
  http://angg.twu.net/emacsconf2019.html
  http://angg.twu.net/#eev

Re: Python.exe in Emacs26 for M$ Windows - REPL problem

[Eli Zaretskii]

> From: Eduardo Ochs <eduardoochs@gmail.com>
> Date: Sun, 26 Jan 2020 21:28:18 -0300
> 
> 1. Where can I find the rationale for why there are a python.exe, a
>    tclsh.exe, and a wish.exe in Emacs26 for Windows?

It was mentioned in some past discussion here, you should be able to
find them in the archives.  In a nutshell, they are parts of some
MSYS2 packages, which are included because they provide libraries used
by Emacs for optional features.  IOW, these executables are there just
by accident, and I'm not surprised that Python doesn't come with its
full suite of packages expected by Python developers.  People who want
really to use Python should install it independently.