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| author | Pablo Galindo <Pablogsal@gmail.com> | 2020-07-27 18:20:36 (GMT) |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2020-07-27 18:20:36 (GMT) |
| commit | 72cabb2aa636272e608285f5a6ba83b62be9be4e (patch) | |
| tree | c43c2815b9aa9389413934136c7be9ac514c6081 /Doc/reference | |
| parent | 67987acd5dc9776f55f4e139e2b3d9e7a6434d9f (diff) | |
| download | cpython-72cabb2aa636272e608285f5a6ba83b62be9be4e.zip cpython-72cabb2aa636272e608285f5a6ba83b62be9be4e.tar.gz cpython-72cabb2aa636272e608285f5a6ba83b62be9be4e.tar.bz2 | |
bpo-40939: Use the new grammar for the grammar specification documentation (GH-19969)
(We censor the heck out of actions and some other stuff using a custom "highlighter".)
Co-authored-by: Guido van Rossum <guido@python.org>
Diffstat (limited to 'Doc/reference')
| -rw-r--r-- | Doc/reference/grammar.rst | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/Doc/reference/grammar.rst b/Doc/reference/grammar.rst index 83d0f85..acf8376 100644 --- a/Doc/reference/grammar.rst +++ b/Doc/reference/grammar.rst @@ -1,7 +1,19 @@ Full Grammar specification ========================== -This is the full Python grammar, as it is read by the parser generator and used -to parse Python source files: +This is the full Python grammar, derived directly from the grammar +used to generate the CPython parser (see :source:`Grammar/python.gram`). +The version here omits details related to code generation and +error recovery. -.. literalinclude:: ../../Grammar/Grammar +The notation is a mixture of `EBNF +<https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_form>`_ +and `PEG <https://en.wikipedia.org/wiki/Parsing_expression_grammar>`_. +In particular, ``&`` followed by a symbol, token or parenthesized +group indicates a positive lookahead (i.e., is required to match but +not consumed), while ``!`` indicates a negative lookahead (i.e., is +required _not_ to match). We use the ``|`` separator to mean PEG's +"ordered choice" (written as ``/`` in traditional PEG grammars). + +.. literalinclude:: ../../Grammar/python.gram + :language: peg |