This PR adds support for float-style formatting for `Fraction` objects: it supports the `"e"`, `"E"`, `"f"`, `"F"`, `"g"`, `"G"` and `"%"` presentation types, and all the various bells and whistles of the formatting mini-language for those presentation types. The behaviour almost exactly matches that of `float`, but the implementation works with the exact `Fraction` value and does not do an intermediate conversion to `float`, and so avoids loss of precision or issues with numbers that are outside the dynamic range of the `float` type.
Note that the `"n"` presentation type is _not_ supported. That support could be added later if people have a need for it.
There's one corner-case where the behaviour differs from that of float: for the `float` type, if explicit alignment is specified with a fill character of `'0'` and alignment type `'='`, then thousands separators (if specified) are inserted into the padding string:
```python
>>> format(3.14, '0=11,.2f')
'0,000,003.14'
```
The exact same effect can be achieved by using the `'0'` flag:
```python
>>> format(3.14, '011,.2f')
'0,000,003.14'
```
For `Fraction`, only the `'0'` flag has the above behaviour with respect to thousands separators: there's no special-casing of the particular `'0='` fill-character/alignment combination. Instead, we treat the fill character `'0'` just like any other:
```python
>>> format(Fraction('3.14'), '0=11,.2f')
'00000003.14'
>>> format(Fraction('3.14'), '011,.2f')
'0,000,003.14'
```
The `Fraction` formatter is also stricter about combining these two things: it's not permitted to use both the `'0'` flag _and_ explicit alignment, on the basis that we should refuse the temptation to guess in the face of ambiguity. `float` is less picky:
```python
>>> format(3.14, '0<011,.2f')
'3.140000000'
>>> format(Fraction('3.14'), '0<011,.2f')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/mdickinson/Repositories/python/cpython/Lib/fractions.py", line 414, in __format__
raise ValueError(
ValueError: Invalid format specifier '0<011,.2f' for object of type 'Fraction'; can't use explicit alignment when zero-padding
```
While the documentation for `optparse` mentioned that both `store_const` and
`append_const` store a constant value, it was not clear where this value was
coming from.
A link to `Option.const` makes this explicit.
The documentation for `rglob` did not mention what `pattern` actually
is.
Mentioning and linking to `fnmatch` makes this explicit, as the
documentation for `fnmatch` both shows the syntax and some explanation.
* Update description of stdout, stderr, and stdin.
Changes:
- Move the ``None`` option (which is default) to the front of the list
of input options
- Move the ``None`` option description up to make the default behavior
more clear (No redirection)
- Remove mention of Child File Descriptors from ``None`` option description
The zipfile.Path open() and read_text() encoding parameter can be supplied as a positional argument without causing a TypeError again. 3.10.0b1 included a regression that made it keyword only.
Documentation update included as users writing code to be compatible with a wide range of versions will need to consider this for some time.
Partially revert changes made in GH-93453.
asyncio.DefaultEventLoopPolicy.get_event_loop() now emits a
DeprecationWarning and creates and sets a new event loop instead of
raising a RuntimeError if there is no current event loop set.
Co-authored-by: Guido van Rossum <gvanrossum@gmail.com>
* Clarify the meaning of the oparg for CACHE and COPY opcode in dis doc
* Use STACK to describe stack operation in analogy with a Python list
* Remove (delta) from BEFORE_WITH since BEFORE_WITH does not take an argument
* Fix the description of the stack impact of multiple opcodes
- Use "drive", not "drive letter", because of UNC paths
- Previous components are not thrown away from relative drive letters
- Use "segment" instead of "component" for consistency with pathlib
- Other miscellaneous improvements
The behaviour is fully explained a couple paragraphs above, but it may be useful to have a brief example to cover the behaviour.
Automerge-Triggered-By: GH:hauntsaninja
- Remove first link to lexical definition of integer literal, since it
doesn't apply (differs in handling of leading zeros, base needs to be
explicitly specified, unicode digits are allowed)
- Better describe handling of leading zeros, unicode digits, underscores
- Base 0 does not work exactly as like a code literal, since it allows
Unicode digits. Link code literal to lexical definition of integer
literal.
All the arguments are positional-only.
The current status after #99476 seems to be to not use positional-only
markers in documentation, hence I've simply removed it.
