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Diffstat (limited to 'Doc/reference/introduction.rst')
| -rw-r--r-- | Doc/reference/introduction.rst | 21 |
1 files changed, 8 insertions, 13 deletions
diff --git a/Doc/reference/introduction.rst b/Doc/reference/introduction.rst index 0d53719..4da1606 100644 --- a/Doc/reference/introduction.rst +++ b/Doc/reference/introduction.rst @@ -22,11 +22,12 @@ language, maybe you could volunteer your time --- or invent a cloning machine It is dangerous to add too many implementation details to a language reference document --- the implementation may change, and other implementations of the -same language may work differently. On the other hand, there is currently only -one Python implementation in widespread use (although alternate implementations -exist), and its particular quirks are sometimes worth being mentioned, -especially where the implementation imposes additional limitations. Therefore, -you'll find short "implementation notes" sprinkled throughout the text. +same language may work differently. On the other hand, CPython is the one +Python implementation in widespread use (although alternate implementations +continue to gain support), and its particular quirks are sometimes worth being +mentioned, especially where the implementation imposes additional limitations. +Therefore, you'll find short "implementation notes" sprinkled throughout the +text. Every Python implementation comes with a number of built-in and standard modules. These are documented in :ref:`library-index`. A few built-in modules @@ -88,11 +89,7 @@ implementation you're using. Notation ======== -.. index:: - single: BNF - single: grammar - single: syntax - single: notation +.. index:: BNF, grammar, syntax, notation The descriptions of lexical analysis and syntax use a modified BNF grammar notation. This uses the following style of definition: @@ -118,9 +115,7 @@ meaningful to separate tokens. Rules are normally contained on a single line; rules with many alternatives may be formatted alternatively with each line after the first beginning with a vertical bar. -.. index:: - single: lexical definitions - single: ASCII@ASCII +.. index:: lexical definitions, ASCII In lexical definitions (as the example above), two more conventions are used: Two literal characters separated by three dots mean a choice of any single |