petite python problem

This works for BASIC:-

*basic
ARM BBC BASIC V (C) Acorn 1989
>SYS "OS_Byte",0
RISC OS 5.29 (02 Nov 2020)

But I get no output from this in Python

*python3
Python 3.8.12+ (riscos-1, Sep  8 2021, 10:35:02)
....
>>> from swi import swi
>>> swi("OS_Byte","i",0)

Can anyone cast a bit of light here?

Is it perhaps important that the response to OS_Byte 0 is returned as an error block?

You’re probably on the right track there! Python likely thinks that OS_Byte 0 has failed since it sets the V flag.

A little odd – i’d expected it to raise a swi.error exception like

swi(“OS_ClI”,“s”,“FX 0”)

does.

I’ve only had a very quick look but can’t see why OS_Byte 0 doesn’t.

Think I’ve got it.

swi.swi(“OS_Byte”,“ii”,0,0)

is what you want.

Otherwise R1 is undefined, and if it’s non-zero you’ll get the machine info returned instead.

I think BASIC defaults unset regs to 0.

swi.swi(“OS_Byte”,“ii”,0,0)
is what you want.

Thanks very much – I have spent the last hour trying different things to get it to work.

Here is another petty python puzzle for a idle moment on a Sunday afternoon.
This works:-

import os
os.system('echo hello world')

import swi
swi.swi('OS_CLI','s','echo hello world')

 *basic
 >SYS "OS_CLI","echo hello world"
 >OSCLI "echo hello world"

Here I see the following:

Python 3.8.8+ (riscos-1, Feb 22 2021, 21:48:54) 
[GCC 4.7.4] on riscos
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.system('echo hello world')
hello world
0
>>> import swi
>>> swi.swi('OS_CLI', 's','echo hello world')
hello world
>>> 

I get the same as Andrew apart from:

Python 3.8.12+ (riscos-1, Sep 8 2021, 10:35:02)
[GCC 4.7.4] on riscos

Curious – this is what I get …

Python 3.8.12+ (riscos-1, Sep  8 2021, 10:35:02)
[GCC 4.7.4] on riscos
Type "help", "copyright", "credits" or "license" for more information.
>>> import swi
>>> swi.swi("OS_CLI","s","echo hello world")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
swi.error: Unable to start application

I get the same error using python 3.10

*python310
Python 3.10.0a5+ (riscos-1, Feb  8 2021, 10:58:52)
[GCC 4.7.4] on riscos
Type "help", snip .....
>>> import swi
>>> swi.swi("OS_CLI","s","echo hello world")
.........
swi.error: Unable to start application

Not sure what “application” means here. Is it the star command *echo, or OS_CLI?
FWIW other uses of swi “OS_CLI” work ok and *echo works with os.system

Python 3.8.8+ (riscos-1, Feb 22 2021, 21:48:54) 
[GCC 4.7.4] on riscos
Type "help", "copyright", "credits" or "license" for more information.
>>> import os
>>> os.system('echo hello world')
hello world
0
>>> import swi
>>> swi.swi ('OS_CLI','s','echo hello world')
hello world
swi.error: SWI name not known
>>> swi.swi("OS_CLI","s","echo hello world")
hello world
>>> 

Hmm!

As you intend to check your installation, it’s probably worth mentioning an observation.

I discovered two versions of the Python riscos_toolbox pip (0-1-0 and 0-2-0); the first version works with the toolbox demo program !tbxeg, and the second version doesn’t.

I haven’t found a way to revert to the earlier version.

Hmm!

Indeed!
David I notice that you are using single quotes, whereas I used double. Don’t suppose it makes a difference but I am clutching at straws here.

I have just tried with Python 27 with the same failure:

Python 2.7.2 (default, Jan 10 2013, 13:22:44)
[GCC 4.1.2 (GCCSDK GCC 4.1.2 Release 3 Development)] on riscos
Type "help".....
>>> import swi
>>> swi.swi("OS_CLI","s","echo hello world")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
swi.error: Unable to start application
>>> 

So it fails on 2.7, 3.8, and 3.10 – what the failures have in common is that they are all on the same machine. ARMX6.
I have just tried the code using python27 on a pi4B and it works.
So it looks to me as if the problem may not be python but some incompatibility in my software. Where to begin!

what the failures have in common is that they are all on the same machine. ARMX6.

I was testing on my ARMX6 5.29 (01-Feb-22) and did not get the error.

Doug I didn’t mean to suggest it was a generic ARMX6 problem but that the errors were happening on the same machine which hapens to be an ARMX6.
It fails on three differnt versions of python, but does works on another machine of mine. Conclusion, it is not a python problem.

Thanks for the clarification John and it does indeed seem the plausable explanation though I’ve often found that keeping an open mind sometimes gets you out of the dead end you can end up in :-)

I discovered two versions of the Python riscos_toolbox pip (0-1-0 and 0-2-0); the first version works with the toolbox demo program !tbxeg, and the second version doesn’t.

There is only one on my machine in !PythonSite.Python38.Site-Packages
and is level 0.1.0.
It was installed using Pip.
Where are yours?

I haven’t found a way to revert to the earlier version.

python3 -m pip uninstall riscos_toolbox

python310 -m pip uninstall riscos_toolbox

Thank you, John; I discovered the anomaly when creating a new Python install on another machine. Whilst I was moving between devices, I removed the riscos_toolbox 0-1-0 from the machine where the example had worked to validate my assumption that it was the newer version. I must admit I hadn’t considered not being able to revert to an earlier version then.

pip38 uninstall riscos_toolbox
Found existing installation: riscos-toolbox 0-2-0
Uninstalling riscos-toolbox-0-2-0:
  Would remove:
    hostfs::hostfs.$.!boot.resources.!pythonsite.python38.site-packages.riscos_toolbox-0/2/0/dist-info.*
    hostfs::hostfs.$.!boot.resources.!pythonsite.python38.site-packages.riscos_toolbox.*
Proceed (y/n)? y
  Successfully uninstalled riscos-toolbox-0-2-0
*pip38 install riscos_toolbox
Collecting riscos_toolbox
  Downloading riscos_toolbox-0.2.0-py3-none-any.whl (10 kB)
Installing collected packages: riscos-toolbox
Successfully installed riscos-toolbox-0-2-0

I discovered two versions of the Python riscos_toolbox pip (0-1-0 and 0-2-0); the first version works with the toolbox demo program !tbxeg, and the second version doesn’t.

I haven’t found a way to revert to the earlier version.

Andrew, I have posted a response to your problem on another thread that deals specifically with !TbxTest and old versions. (Thread: Python38 issue)

I am also working on instructions for getting !TbxTest to work as the original has some problems, and will post it there also.

This thread is best used for simple puzzles.