On 6/19/2021 5:36 PM, André Roberge wrote:
Hi everyone,
With the latest Python beta version (3.10.0), IDLE's shell now supports
custom exception hooks.
(https://docs.python.org/3.10/whatsnew/3.10.html#idle-and-idlelib
<https://docs.python.org/3.10/whatsnew/3.10.html#idle-and-idlelib>)
However, this support is incomplete since when SyntaxErrors are raised
for code entered in IDLE's shell, the information is not passed to
custom exception hooks.
A while ago, I filed an issue https://bugs.python.org/issue43476
<https://bugs.python.org/issue43476> suggesting that it would be "nice"
to make this possible. I tried on my own, but have not been able to
figure out how to do it. However, as noted in the issue, I found a
workaround of sorts: adding a single line of code to save the offending
code into a specially named file. This file can then be accessed like
any others allowing someone to recreate the SyntaxError and handle it as
desired.
I gave more feedback on the issue. IDLE already has a bit of code for a
3rd party package, V-IDLE?, which I am not sure is still current.
For those that are curious to see what it may look like, I suggest you
install "friendly" from PyPI, and add the one line to your Python 3.10
idlelib.pyshell.py <http://idlelib.pyshell.py> file as mentioned in the
issue linked above. This is a sample session illustrating what it looks
like [it's more impressive with colours, of course! ;-) ]
==========================================
>>> from friendly.idle import *
I hope you document the alternative for anyone wanting to isolate f.i
functions: `import friendly.idle as fi` or
`from friendly import idle as fi`.
In any case, fi executes in the user process. Do you use the rpc
connection to query linecache in the IDLE process?
>>> install()
WARNING
Friendly cannot handle SyntaxErrors for code entered in the shell.
>>> from math import pi
>>> tau = 2pi
SyntaxError: invalid decimal literal
>>> explain("syntax") # Special friendly command needed to recreate
the exception
On the issue, I suggested de-serializing the original rather than
recompiling.
File "<SyntaxError>", line 1
tau = 2pi
^
SyntaxError: invalid decimal literal
Perhaps you forgot a multiplication operator, 2 * pi.
>>> why()
Valid names cannot begin with a number.
Perhaps you forgot a multiplication operator, 2 * pi.
>>> what()
A SyntaxError occurs when Python cannot understand your code.
>>> where()
Python could not understand the code in the file
'<SyntaxError>'
beyond the location indicated by ^.
-->1: tau = 2pi
^
=====================
You can also simply type "Friendly" at a prompt, and a special __repr__
will provide some quick help. (This is not yet documented.) And, of
course, Friendly makes uses of the new support for custom exception hook
for runtime errors.
It is possible that I will change explain("syntax") to
explain("SyntaxError") in a future version - depending on feedback and
assuming there is some support for a change in IDLE's code as described.
I think it is fine as is.
If any of you try it out, I'd be really curious to see what you think of
this.
More information about friendly and IDLE can be found at
https://aroberge.github.io/friendly-traceback-docs/docs/html/idle_repl.html
<https://aroberge.github.io/friendly-traceback-docs/docs/html/idle_repl.html>
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