bpo-38096: Clean up the "struct sequence" / "named tuple" docs (GH-15895)

* bpo-38096: Clean up the "struct sequence" / "named tuple" docs

* Fix remaining occurrences of "struct sequence"

* Repair a user visible docstring

4 files changed, 31 insertions, 28 deletions

diff --git a/Doc/glossary.rst b/Doc/glossary.rst
index 0f2a3a1..84d0fca 100644
--- a/Doc/glossary.rst
+++ b/Doc/glossary.rst
@@ -739,17 +739,28 @@ Glossary
       also :term:`immutable`.
 
    named tuple
-      Any tuple-like class whose indexable elements are also accessible using
-      named attributes (for example, :func:`time.localtime` returns a
-      tuple-like object where the *year* is accessible either with an
-      index such as ``t[0]`` or with a named attribute like ``t.tm_year``).
-
-      A named tuple can be a built-in type such as :class:`time.struct_time`,
-      or it can be created with a regular class definition.  A full featured
-      named tuple can also be created with the factory function
-      :func:`collections.namedtuple`.  The latter approach automatically
-      provides extra features such as a self-documenting representation like
-      ``Employee(name='jones', title='programmer')``.
+      The term "named tuple" applies to any type or class that inherits from
+      tuple and whose indexable elements are also accessible using named
+      attributes.  The type or class may have other features as well.
+
+      Several built-in types are named tuples, including the values returned
+      by :func:`time.localtime` and :func:`os.stat`.  Another example is
+      :data:`sys.float_info`::
+
+           >>> sys.float_info[1]                   # indexed access
+           1024
+           >>> sys.float_info.max_exp              # named field access
+           1024
+           >>> isinstance(sys.float_info, tuple)   # kind of tuple
+           True
+
+      Some named tuples are built-in types (such as the above examples).
+      Alternatively, a named tuple can be created from a regular class
+      definition that inherits from :class:`tuple` and that defines named
+      fields.  Such as class can be written by hand or it can be created with
+      the factory function :func:`collections.namedtuple`.  The latter
+      technique also adds some extra methods that may not be found in
+      hand-written or built-in named tuples.
 
    namespace
       The place where a variable is stored.  Namespaces are implemented as
@@ -1032,14 +1043,6 @@ Glossary
       an :term:`expression` or one of several constructs with a keyword, such
       as :keyword:`if`, :keyword:`while` or :keyword:`for`.
 
-   struct sequence
-      A tuple with named elements. Struct sequences expose an interface similar
-      to :term:`named tuple` in that elements can be accessed either by
-      index or as an attribute. However, they do not have any of the named tuple
-      methods like :meth:`~collections.somenamedtuple._make` or
-      :meth:`~collections.somenamedtuple._asdict`. Examples of struct sequences
-      include :data:`sys.float_info` and the return value of :func:`os.stat`.
-
    text encoding
       A codec which encodes Unicode strings to bytes.
 
diff --git a/Doc/library/sys.rst b/Doc/library/sys.rst
index 01df026..a5528f7 100644
--- a/Doc/library/sys.rst
+++ b/Doc/library/sys.rst
@@ -408,7 +408,7 @@ always available.
 
 .. data:: flags
 
-   The :term:`struct sequence` *flags* exposes the status of command line
+   The :term:`named tuple` *flags* exposes the status of command line
    flags. The attributes are read only.
 
    ============================= =============================
@@ -450,7 +450,7 @@ always available.
 
 .. data:: float_info
 
-   A :term:`struct sequence` holding information about the float type. It
+   A :term:`named tuple` holding information about the float type. It
    contains low level information about the precision and internal
    representation.  The values correspond to the various floating-point
    constants defined in the standard header file :file:`float.h` for the 'C'
@@ -782,7 +782,7 @@ always available.
 
 .. data:: hash_info
 
-   A :term:`struct sequence` giving parameters of the numeric hash
+   A :term:`named tuple` giving parameters of the numeric hash
    implementation.  For more details about hashing of numeric types, see
    :ref:`numeric-hash`.
 
@@ -830,7 +830,7 @@ always available.
 
    This is called ``hexversion`` since it only really looks meaningful when viewed
    as the result of passing it to the built-in :func:`hex` function.  The
-   :term:`struct sequence`  :data:`sys.version_info` may be used for a more
+   :term:`named tuple`  :data:`sys.version_info` may be used for a more
    human-friendly encoding of the same information.
 
    More details of ``hexversion`` can be found at :ref:`apiabiversion`.
@@ -882,7 +882,7 @@ always available.
 
 .. data:: int_info
 
-   A :term:`struct sequence` that holds information about Python's internal
+   A :term:`named tuple` that holds information about Python's internal
    representation of integers.  The attributes are read only.
 
    .. tabularcolumns:: |l|L|
@@ -1457,7 +1457,7 @@ always available.
 
 .. data:: thread_info
 
-   A :term:`struct sequence` holding information about the thread
+   A :term:`named tuple` holding information about the thread
    implementation.
 
    .. tabularcolumns:: |l|p{0.7\linewidth}|
diff --git a/Doc/whatsnew/3.3.rst b/Doc/whatsnew/3.3.rst
index ea03684..f1a033c 100644
--- a/Doc/whatsnew/3.3.rst
+++ b/Doc/whatsnew/3.3.rst
@@ -2002,8 +2002,8 @@ platform-independent fashion.  (Contributed by Ross Lagerwall in
 sys
 ---
 
-The :mod:`sys` module has a new :data:`~sys.thread_info` :term:`struct
-sequence` holding information about the thread implementation
+The :mod:`sys` module has a new :data:`~sys.thread_info` :term:`named
+tuple` holding information about the thread implementation
 (:issue:`11223`).
 
 
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst
index 845e327..822ba81 100644
--- a/Doc/whatsnew/3.4.rst
+++ b/Doc/whatsnew/3.4.rst
@@ -1849,7 +1849,7 @@ Python's default implementation to a SipHash implementation on platforms that
 have a 64 bit data type.  Any performance differences in comparison with the
 older FNV algorithm are trivial.
 
-The PEP adds additional fields to the :attr:`sys.hash_info` struct sequence to
+The PEP adds additional fields to the :attr:`sys.hash_info` named tuple to
 describe the hash algorithm in use by the currently executing binary.  Otherwise,
 the PEP does not alter any existing CPython APIs.