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authorStanley <46876382+slateny@users.noreply.github.com>2022-10-07 19:15:41 (GMT)
committerGitHub <noreply@github.com>2022-10-07 19:15:41 (GMT)
commit3a7e955858b21b6fc35f826d0975a26ac39f50de (patch)
treead0e82ea9cd612f2cc9566c44eff18b52927a1e0
parentfde74be61bfdc79afad5dfb9496688370368c179 (diff)
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gh-96265: Fix some formatting in faq/design.rst (#96924)
Co-authored-by: Ezio Melotti <ezio.melotti@gmail.com> Co-authored-by: C.A.M. Gerlach <CAM.Gerlach@Gerlach.CAM>
-rw-r--r--Doc/faq/design.rst58
1 files changed, 31 insertions, 27 deletions
diff --git a/Doc/faq/design.rst b/Doc/faq/design.rst
index ccdc9bf..763222a 100644
--- a/Doc/faq/design.rst
+++ b/Doc/faq/design.rst
@@ -62,7 +62,7 @@ and think it is a bug in Python. It's not. This has little to do with Python,
and much more to do with how the underlying platform handles floating-point
numbers.
-The :class:`float` type in CPython uses a C ``double`` for storage. A
+The :class:`float` type in CPython uses a C :c:type:`double` for storage. A
:class:`float` object's value is stored in binary floating-point with a fixed
precision (typically 53 bits) and Python uses C operations, which in turn rely
on the hardware implementation in the processor, to perform floating-point
@@ -129,7 +129,7 @@ reference or call the method from a particular class. In C++, if you want to
use a method from a base class which is overridden in a derived class, you have
to use the ``::`` operator -- in Python you can write
``baseclass.methodname(self, <argument list>)``. This is particularly useful
-for :meth:`__init__` methods, and in general in cases where a derived class
+for :meth:`~object.__init__` methods, and in general in cases where a derived class
method wants to extend the base class method of the same name and thus has to
call the base class method somehow.
@@ -232,7 +232,8 @@ Similar methods exist for bytes and bytearray objects.
How fast are exceptions?
------------------------
-A try/except block is extremely efficient if no exceptions are raised. Actually
+A :keyword:`try`/:keyword:`except` block is extremely efficient if no exceptions
+are raised. Actually
catching an exception is expensive. In versions of Python prior to 2.0 it was
common to use this idiom::
@@ -352,7 +353,7 @@ will probably run out of file descriptors::
c = f.read(1)
Indeed, using CPython's reference counting and destructor scheme, each new
-assignment to *f* closes the previous file. With a traditional GC, however,
+assignment to ``f`` closes the previous file. With a traditional GC, however,
those file objects will only get collected (and closed) at varying and possibly
long intervals.
@@ -376,10 +377,10 @@ Python to work with it.)
Traditional GC also becomes a problem when Python is embedded into other
applications. While in a standalone Python it's fine to replace the standard
-malloc() and free() with versions provided by the GC library, an application
-embedding Python may want to have its *own* substitute for malloc() and free(),
+``malloc()`` and ``free()`` with versions provided by the GC library, an application
+embedding Python may want to have its *own* substitute for ``malloc()`` and ``free()``,
and may not want Python's. Right now, CPython works with anything that
-implements malloc() and free() properly.
+implements ``malloc()`` and ``free()`` properly.
Why isn't all memory freed when CPython exits?
@@ -401,14 +402,15 @@ Why are there separate tuple and list data types?
Lists and tuples, while similar in many respects, are generally used in
fundamentally different ways. Tuples can be thought of as being similar to
-Pascal records or C structs; they're small collections of related data which may
+Pascal ``records`` or C ``structs``; they're small collections of related data which may
be of different types which are operated on as a group. For example, a
Cartesian coordinate is appropriately represented as a tuple of two or three
numbers.
Lists, on the other hand, are more like arrays in other languages. They tend to
hold a varying number of objects all of which have the same type and which are
-operated on one-by-one. For example, ``os.listdir('.')`` returns a list of
+operated on one-by-one. For example, :func:`os.listdir('.') <os.listdir>`
+returns a list of
strings representing the files in the current directory. Functions which
operate on this output would generally not break if you added another file or
two to the directory.
@@ -444,9 +446,9 @@ far) under most circumstances, and the implementation is simpler.
Dictionaries work by computing a hash code for each key stored in the dictionary
using the :func:`hash` built-in function. The hash code varies widely depending
-on the key and a per-process seed; for example, "Python" could hash to
--539294296 while "python", a string that differs by a single bit, could hash
-to 1142331976. The hash code is then used to calculate a location in an
+on the key and a per-process seed; for example, ``'Python'`` could hash to
+``-539294296`` while ``'python'``, a string that differs by a single bit, could hash
+to ``1142331976``. The hash code is then used to calculate a location in an
internal array where the value will be stored. Assuming that you're storing
keys that all have different hash values, this means that dictionaries take
constant time -- O(1), in Big-O notation -- to retrieve a key.
@@ -497,7 +499,8 @@ Some unacceptable solutions that have been proposed:
There is a trick to get around this if you need to, but use it at your own risk:
You can wrap a mutable structure inside a class instance which has both a
-:meth:`__eq__` and a :meth:`__hash__` method. You must then make sure that the
+:meth:`~object.__eq__` and a :meth:`~object.__hash__` method.
+You must then make sure that the
hash value for all such wrapper objects that reside in a dictionary (or other
hash based structure), remain fixed while the object is in the dictionary (or
other structure). ::
@@ -528,7 +531,7 @@ is True``) then ``hash(o1) == hash(o2)`` (ie, ``o1.__hash__() == o2.__hash__()``
regardless of whether the object is in a dictionary or not. If you fail to meet
these restrictions dictionaries and other hash based structures will misbehave.
-In the case of ListWrapper, whenever the wrapper object is in a dictionary the
+In the case of :class:`!ListWrapper`, whenever the wrapper object is in a dictionary the
wrapped list must not change to avoid anomalies. Don't do this unless you are
prepared to think hard about the requirements and the consequences of not
meeting them correctly. Consider yourself warned.
@@ -581,9 +584,9 @@ exhaustive test suites that exercise every line of code in a module.
An appropriate testing discipline can help build large complex applications in
Python as well as having interface specifications would. In fact, it can be
better because an interface specification cannot test certain properties of a
-program. For example, the :meth:`append` method is expected to add new elements
+program. For example, the :meth:`list.append` method is expected to add new elements
to the end of some internal list; an interface specification cannot test that
-your :meth:`append` implementation will actually do this correctly, but it's
+your :meth:`list.append` implementation will actually do this correctly, but it's
trivial to check this property in a test suite.
Writing test suites is very helpful, and you might want to design your code to
@@ -599,14 +602,14 @@ Why is there no goto?
In the 1970s people realized that unrestricted goto could lead
to messy "spaghetti" code that was hard to understand and revise.
In a high-level language, it is also unneeded as long as there
-are ways to branch (in Python, with ``if`` statements and ``or``,
-``and``, and ``if-else`` expressions) and loop (with ``while``
-and ``for`` statements, possibly containing ``continue`` and ``break``).
+are ways to branch (in Python, with :keyword:`if` statements and :keyword:`or`,
+:keyword:`and`, and :keyword:`if`/:keyword:`else` expressions) and loop (with :keyword:`while`
+and :keyword:`for` statements, possibly containing :keyword:`continue` and :keyword:`break`).
One can also use exceptions to provide a "structured goto"
that works even across
function calls. Many feel that exceptions can conveniently emulate all
-reasonable uses of the "go" or "goto" constructs of C, Fortran, and other
+reasonable uses of the ``go`` or ``goto`` constructs of C, Fortran, and other
languages. For example::
class label(Exception): pass # declare a label
@@ -620,7 +623,7 @@ languages. For example::
...
This doesn't allow you to jump into the middle of a loop, but that's usually
-considered an abuse of goto anyway. Use sparingly.
+considered an abuse of ``goto`` anyway. Use sparingly.
Why can't raw strings (r-strings) end with a backslash?
@@ -652,7 +655,7 @@ If you're trying to build a pathname for a DOS command, try e.g. one of ::
Why doesn't Python have a "with" statement for attribute assignments?
---------------------------------------------------------------------
-Python has a 'with' statement that wraps the execution of a block, calling code
+Python has a :keyword:`with` statement that wraps the execution of a block, calling code
on the entrance and exit from the block. Some languages have a construct that
looks like this::
@@ -679,13 +682,13 @@ For instance, take the following incomplete snippet::
with a:
print(x)
-The snippet assumes that "a" must have a member attribute called "x". However,
+The snippet assumes that ``a`` must have a member attribute called ``x``. However,
there is nothing in Python that tells the interpreter this. What should happen
-if "a" is, let us say, an integer? If there is a global variable named "x",
-will it be used inside the with block? As you see, the dynamic nature of Python
+if ``a`` is, let us say, an integer? If there is a global variable named ``x``,
+will it be used inside the :keyword:`with` block? As you see, the dynamic nature of Python
makes such choices much harder.
-The primary benefit of "with" and similar language features (reduction of code
+The primary benefit of :keyword:`with` and similar language features (reduction of code
volume) can, however, easily be achieved in Python by assignment. Instead of::
function(args).mydict[index][index].a = 21
@@ -714,7 +717,8 @@ Why don't generators support the with statement?
For technical reasons, a generator used directly as a context manager
would not work correctly. When, as is most common, a generator is used as
an iterator run to completion, no closing is needed. When it is, wrap
-it as "contextlib.closing(generator)" in the 'with' statement.
+it as :func:`contextlib.closing(generator) <contextlib.closing>`
+in the :keyword:`with` statement.
Why are colons required for the if/while/def/class statements?