Some comments on PL/Python documentation
The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/17/plpython-data.html
Description:
Hello,
In my opinion, some phrases on this page are not quite correct.
44.2.4. Composite Types
You say: '...Object (any object providing method __getattr__)...'
Actually, the object class provides the __getattribute__() method but not
the __getattr__() method.
See https://docs.python.org/3/reference/datamodel.html#object.__getattr__
44.2.5. Set-Returning Functions
1. You say: '...Sequence type (tuple, list, set)...'
Being an unordered collection, sets do not record element position or order
of insertion. Accordingly, sets do not support indexing, slicing, or other
sequence-like behavior.
See
https://docs.python.org/3/library/stdtypes.html#set-types-set-frozenset
2. You say: '...Iterator (any object providing __iter__ and next
methods)...'
Actually, the iterator objects must support the __next__() method.
See https://docs.python.org/3/glossary.html#term-iterator
Regards,
Bogdan Grigorenko
On 29.12.24 01:48, PG Doc comments form wrote:
Page: https://www.postgresql.org/docs/17/plpython-data.html
Description:Hello,
In my opinion, some phrases on this page are not quite correct.44.2.4. Composite Types
You say: '...Object (any object providing method __getattr__)...'
Actually, the object class provides the __getattribute__() method but not
the __getattr__() method.
See https://docs.python.org/3/reference/datamodel.html#object.__getattr__
Yes, this looks slightly inaccurate. I'm not sure __getattribute__ is
fully correct either, because types can also implement other ways of
returning attributes, especially if they are implemented in C. Is there
a neutral and accurate way to describe this?
44.2.5. Set-Returning Functions
1. You say: '...Sequence type (tuple, list, set)...'
Being an unordered collection, sets do not record element position or order
of insertion. Accordingly, sets do not support indexing, slicing, or other
sequence-like behavior.
See
https://docs.python.org/3/library/stdtypes.html#set-types-set-frozenset
I think this is correct as it is. Python sets can be iterated over, so
this works. Note that earlier in the page under composite types it says
"but not a set because it is not indexable", so this distinction was
taken into consideration.
2. You say: '...Iterator (any object providing __iter__ and next
methods)...'
Actually, the iterator objects must support the __next__() method.
See https://docs.python.org/3/glossary.html#term-iterator
Yes, this was recently fixed already and will appear in the next patch
release.
On 08.01.25 09:45, Peter Eisentraut wrote:
44.2.5. Set-Returning Functions
1. You say: '...Sequence type (tuple, list, set)...'
Being an unordered collection, sets do not record element position or
order
of insertion. Accordingly, sets do not support indexing, slicing, or
other
sequence-like behavior.
See
https://docs.python.org/3/library/stdtypes.html#set-types-set-frozensetI think this is correct as it is. Python sets can be iterated over, so
this works. Note that earlier in the page under composite types it says
"but not a set because it is not indexable", so this distinction was
taken into consideration.
I have added a test for returning Python sets from SETOF functions. It
makes sense to test this if the documentation claims it.