emacs-orgmode@gnu.org archives
 help / color / mirror / code / Atom feed
From: Norman Walsh <ndw@nwalsh.com>
To: emacs-orgmode@gnu.org
Subject: “Literate” python?
Date: Fri, 29 Nov 2019 11:54:33 -0600	[thread overview]
Message-ID: <m2d0daa7qe.fsf@nwalsh.com> (raw)

[-- Attachment #1: Type: text/plain, Size: 2571 bytes --]

Hi,

I’ve seen a couple of pointers recently to using Org mode and tangle
to write more literate Emacs configurations. I use Org+babel all the
time to write “interactive” documents, so I thought I’d try out tangle
from Org.

I didn’t want to start with something as comlicated as my Emacs
config :-) so I figured I’d kick the tires with a small python
program. That did not end well.

Consider:

#+TITLE: Python literate programming
#+OPTIONS: html-postamble:nil

It starts off as a completely standard Python3 program.

---%<------------------------------------------------------
#+BEGIN_SRC python :tangle yes :weave no
#!/usr/bin/env python3

#+END_SRC

It defines ~a~.

#+BEGIN_SRC python :tangle yes
def a():
    print("a")


#+END_SRC

And ~b~.

#+BEGIN_SRC python :tangle yes
def b():
    print("b")


#+END_SRC

Now ~c~ is a little more complicated:

#+BEGIN_SRC python :tangle yes
def c():
   print("c")
#+END_SRC

Not only does ~c~ print “c”, it calls ~a()~ and ~b()~.

#+BEGIN_SRC python :tangle yes
   b()
   a()
#+END_SRC

Finally, make it importable. Not that you’d want to.

#+BEGIN_SRC python :tangle yes
if __name__ == "__main__":
    main()
#+END_SRC
--->%------------------------------------------------------

That’s the script. It weaves into HTML more-or-less ok (there’s a
weird black box at the front of indented lines, but I can come back to
that later).

It’s a complete mess when tangled.

The extra blank lines between functions (to make pylint happy with
some PEP guideline) have disappeared. I guess I could live with that,
but the complete failure to preserve indention in the penultimate code
block is a show stopper:

#!/usr/bin/env python3

def a():
    print("a")

def b():
    print("b")

def c():
   print("c")

b()
a()

if __name__ == "__main__":
    main()

(Also, why is there an extra blank line before the incorrectly
indented block?)

Is this user error on my part somehow? I suppose I could write my own
version of tangle, though I’m not clear if the whitespace is lost in
the tangle function or in the Org mode data model.

Thoughts?

                                        Be seeing you,
                                          norm

-- 
Norman Walsh <ndw@nwalsh.com> | We discover in ourselves what others
http://nwalsh.com/            | hide from us, and we recognize in
                              | others what we hide from
                              | ourselves.--Vauvenargues

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 832 bytes --]

             reply	other threads:[~2019-11-29 17:54 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-29 17:54 Norman Walsh [this message]
2019-11-29 19:22 ` Berry, Charles
2019-11-29 21:09   ` Norman Walsh
2019-11-29 19:30 ` George Mauer
2019-11-29 21:10   ` Norman Walsh
2019-11-29 22:32 ` Diego Zamboni
2019-11-30  0:25   ` Norman Walsh

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

  List information: https://www.orgmode.org/

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=m2d0daa7qe.fsf@nwalsh.com \
    --to=ndw@nwalsh.com \
    --cc=emacs-orgmode@gnu.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
Code repositories for project(s) associated with this public inbox

	https://git.savannah.gnu.org/cgit/emacs/org-mode.git

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).