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web/python-docs/_sources/library/token.rst.txt

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+:mod:`token` --- Constants used with Python parse trees
+=======================================================
+
+.. module:: token
+   :synopsis: Constants representing terminal nodes of the parse tree.
+
+.. sectionauthor:: Fred L. Drake, Jr. <fdrake@acm.org>
+
+**Source code:** :source:`Lib/token.py`
+
+--------------
+
+This module provides constants which represent the numeric values of leaf nodes
+of the parse tree (terminal tokens).  Refer to the file :file:`Grammar/Grammar`
+in the Python distribution for the definitions of the names in the context of
+the language grammar.  The specific numeric values which the names map to may
+change between Python versions.
+
+The module also provides a mapping from numeric codes to names and some
+functions.  The functions mirror definitions in the Python C header files.
+
+
+.. data:: tok_name
+
+   Dictionary mapping the numeric values of the constants defined in this module
+   back to name strings, allowing more human-readable representation of parse trees
+   to be generated.
+
+
+.. function:: ISTERMINAL(x)
+
+   Return ``True`` for terminal token values.
+
+
+.. function:: ISNONTERMINAL(x)
+
+   Return ``True`` for non-terminal token values.
+
+
+.. function:: ISEOF(x)
+
+   Return ``True`` if *x* is the marker indicating the end of input.
+
+
+The token constants are:
+
+.. include:: token-list.inc
+
+The following token type values aren't used by the C tokenizer but are needed for
+the :mod:`tokenize` module.
+
+.. data:: COMMENT
+
+   Token value used to indicate a comment.
+
+
+.. data:: NL
+
+   Token value used to indicate a non-terminating newline.  The
+   :data:`NEWLINE` token indicates the end of a logical line of Python code;
+   ``NL`` tokens are generated when a logical line of code is continued over
+   multiple physical lines.
+
+
+.. data:: ENCODING
+
+   Token value that indicates the encoding used to decode the source bytes
+   into text. The first token returned by :func:`tokenize.tokenize` will
+   always be an ``ENCODING`` token.
+
+
+.. data:: TYPE_COMMENT
+   :noindex:
+
+   Token value indicating that a type comment was recognized.  Such
+   tokens are only produced when :func:`ast.parse()` is invoked with
+   ``type_comments=True``.
+
+
+.. versionchanged:: 3.5
+   Added :data:`AWAIT` and :data:`ASYNC` tokens.
+
+.. versionchanged:: 3.7
+   Added :data:`COMMENT`, :data:`NL` and :data:`ENCODING` tokens.
+
+.. versionchanged:: 3.7
+   Removed :data:`AWAIT` and :data:`ASYNC` tokens. "async" and "await" are
+   now tokenized as :data:`NAME` tokens.
+
+.. versionchanged:: 3.8
+   Added :data:`TYPE_COMMENT`, :data:`TYPE_IGNORE`, :data:`COLONEQUAL`.
+   Added :data:`AWAIT` and :data:`ASYNC` tokens back (they're needed
+   to support parsing older Python versions for :func:`ast.parse` with
+   ``feature_version`` set to 6 or lower).