some problems for an introductory python test

[Dennis Lee Bieber]

On Thu, 12 Aug 2021 12:09:58 -0300, Hope Rouselle <hrouselle at jevedi.com>
declaimed the following:


>How is it possible that Microsoft would take part of the code of OS/2?
>Did IBM just hand it to them?
>

	Because IBM subcontracted (IE: "paid") M$ to create an OS with XYZ
features for their latest PC (under supervision of IBM design team)..

https://en.wikipedia.org/wiki/OS/2

	IBM owned the rights to OS/2, but it was written, for the most part, by
M$ in parallel with M$ own "Windows" 16-bit OS.

>
>Yeah, that's kinda nice.  Isn't that a UNIX design?  A file is a
>sequence of bytes?  Users decide what to put in them?  So OS/2 was
>taking advantage of that to integrate it well with the system.  Windows
>was doing the same, but integrating the system with files in odd ways
>--- such as a registry record to inform the system which programs open
>which files?  (That does sound more messy.)
>

	Not really -- Have you looked at what a hash Linux graphical interfaces
require to associate file types with how to open said files?

	On my Debian (VirtualBox) there is:

wulfraed at debian:~$ cat ~/.config/mimeapps.list 
[Added Associations]
text/html=firefox-esr.desktop;
text/plain=gvim.desktop;
x-scheme-handler/http=exo-web-browser.desktop
x-scheme-handler/https=exo-web-browser.desktop
x-scheme-handler/mailto=exo-mail-reader.desktop
application/xml=gvim.desktop;
text/x-scheme=gvim.desktop;
application/vnd.kde.kxmlguirc=gvim.desktop;
text/x-python=gvim.desktop;
application/x-shellscript=gvim.desktop;

[Default Applications]
wulfraed at debian:~$ 

... and all these

wulfraed at debian:~$ ls /usr/share/applications
atril.desktop				 panel-desktop-handler.desktop
claws-mail.desktop			 panel-preferences.desktop
	...
debian-uxterm.desktop			 python3.7.desktop

	...
org.thonny.Thonny.desktop		 xsane.desktop
org.xfce.Parole.desktop
wulfraed at debian:~$ 

wulfraed at debian:~$ cat /usr/share/applications/python3.7.desktop 
[Desktop Entry]
Name=Python (v3.7)
Comment=Python Interpreter (v3.7)
Exec=/usr/bin/python3.7
Icon=/usr/share/pixmaps/python3.7.xpm
Terminal=true
Type=Application
Categories=Development;
StartupNotify=true
NoDisplay=true
wulfraed at debian:~$ 

wulfraed at debian:~$ cat /etc/mime.types 
###############################################################################
#
#  MIME media types and the extensions that represent them.
#
#  The format of this file is a media type on the left and zero or more
#  filename extensions on the right.  Programs using this file will map
#  files ending with those extensions to the associated type.
#
#  This file is part of the "mime-support" package.  Please report a bug
using
#  the "reportbug" command of the "reportbug" package if you would like new
#  types or extensions to be added.
#
#  The reason that all types are managed by the mime-support package
instead
#  allowing individual packages to install types in much the same way as
they
#  add entries in to the mailcap file is so these types can be referenced
by
#  other programs (such as a web server) even if the specific support
package
#  for that type is not installed.
#
#  Users can add their own types if they wish by creating a ".mime.types"
#  file in their home directory.  Definitions included there will take
#  precedence over those listed here.
#
###############################################################################


application/activemessage
application/andrew-inset			ez
application/annodex				anx
application/applefile
application/atom+xml				atom
	...
application/x-python-code			pyc pyo
	...
text/x-python					py
	...

wulfraed at debian:~$ cat /usr/share/applications/gvim.desktop 
[Desktop Entry]
Name=gVim
GenericName=Text Editor
	...
TryExec=gvim
Exec=gvim -f %F
Terminal=false
Type=Application
Keywords=Text;editor;
Icon=gvim
Categories=Utility;TextEditor;Development;
StartupNotify=true
MimeType=text/english;text/plain;text/x-makefile;text/x-c++hdr;text/x-c++src;text/x-chdr;text/x-csrc;text/x-java;text/x-moc;text/x-pascal;text/x-tcl;text/x-tex;application/x-shellscript;text/x-c;text/x-c++;text/x-python;text/x-python3
wulfraed at debian:~$ 

 
	ALL of that is needed to link a Python source code file (.py) to GVIM
editor, when clicked on from the desktop.

>UNIX's execve() is able to read the first line of an executable and
>invoke its interpreter.  I guess OS/2 was doing precisely that in a
>different way?
>
	No... the UNIX/Linux shebang (and binary file equivalent magic-number)
is a deliberately written part of a file's "data" content (granted, the
linker writes it for executable binaries).

	The description for OS/2 is close to the little used Windows STREAMS
feature.
		https://docs.microsoft.com/en-us/windows/win32/fileio/file-streams
		https://docs.microsoft.com/en-us/windows/win32/fileio/using-streams


>
>I cannot imagine.  I always wondered what REXX was about --- I saw
>programs sometimes written in some website whose name is something like
>Rosetta Code.  REXX looked so weird.  (``Who would program in that?'')

	REXX was created by an IBM researcher who wanted something better than
mainframe JCL (Job Control Language).
		https://en.wikipedia.org/wiki/Rexx


>Yeah, REXX looks horrible at first.  But arbitrary-precision is
>definitely very attractive.  I never liked to deal with floating-point.
>
	Unfortunately, the most commonly available is Regina REXX, and to my
knowledge it did not implement the arbitrary precision feature. Softrware
emulation of multprecision floating point is slooooooooooooooooooowwww!




-- 
	Wulfraed                 Dennis Lee Bieber         AF6VN
	wlfraed at ix.netcom.com    http://wlfraed.microdiversity.freeddns.org/