print / printed approach is too opinionated to be useful #290
Description
BUG/PROBLEM REPORT / FEATURE REQUEST
RestrictingNodeTransformer rewrites usage of print, and expects its output to be retrieved with printed. This is too opinionated for my use case (plus I have existing code that I want to use this on that uses a printed variable for its own purpose). I'd like to simply replace the print builtin with my own implementation that I can do whatever I want with, such as collect output in a file or a StringIO or similar where I can do something with it when execution completes.
Unfortunately it doesn't look like I can do that very easily, since the current print handling seems to be pervasive in the transformer's implementation. Overriding the methods in question seems to mean copy-pasting a lot of code.
I can't find any documentation that explains whether or not there's a good reason __builtins__.print just can't be overridden without all of the mangling that occurs in RestrictingNodeTransformer. Is there? Can you recommend a path forward for me?
What I expect to happen:
I'd love to be able to write a replacement print implementation that works something like:
stdout = StringIO()
stderr = StringIO()
glb = {
'sys': { # over-simplifying but you get the idea
'stdout': stdout,
'stderr': stderr,
},
'__builtins__': {}
}
def my_print(*args, sep=' ', end='\n', file=None, flush=False):
if file is None:
file = glb['sys']['stdout']
print(*args, sep=sep, end=end, file=file, flush=flush)
glb['__builtins__']['print'] = my_print
exec(code, glb, {}, mode='exec')
print(stdout.getvalue()) # "...profit!"What actually happened:
I am forced instead down a _print and PrintCollector journey that requires I modify the code I'm trying to execute by having it do something in the scope of the user code with printed. This seems like it requires a lot of code modification.
What version of Python and Zope/Addons I am using:
RestrictedPython==7.4
Cpython 3.12 on Darwin