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| -rw-r--r-- | Doc/library/functions.rst | 21 |
1 files changed, 12 insertions, 9 deletions
diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst index 817c1f8..2e98825 100644 --- a/Doc/library/functions.rst +++ b/Doc/library/functions.rst @@ -650,20 +650,23 @@ are always available. They are listed here in alphabetical order. sign may be ``'+'`` or ``'-'``; a ``'+'`` sign has no effect on the value produced. The argument may also be a string representing a NaN (not-a-number), or positive or negative infinity. More precisely, the - input must conform to the following grammar after leading and trailing - whitespace characters are removed: + input must conform to the ``floatvalue`` production rule in the following + grammar, after leading and trailing whitespace characters are removed: .. productionlist:: float sign: "+" | "-" infinity: "Infinity" | "inf" nan: "nan" - numeric_value: `floatnumber` | `infinity` | `nan` - numeric_string: [`sign`] `numeric_value` - - Here ``floatnumber`` is the form of a Python floating-point literal, - described in :ref:`floating`. Case is not significant, so, for example, - "inf", "Inf", "INFINITY", and "iNfINity" are all acceptable spellings for - positive infinity. + digitpart: `digit` (["_"] `digit`)* + number: [`digitpart`] "." `digitpart` | `digitpart` ["."] + exponent: ("e" | "E") ["+" | "-"] `digitpart` + floatnumber: number [`exponent`] + floatvalue: [`sign`] (`floatnumber` | `infinity` | `nan`) + + Here ``digit`` is a Unicode decimal digit (character in the Unicode general + category ``Nd``). Case is not significant, so, for example, "inf", "Inf", + "INFINITY", and "iNfINity" are all acceptable spellings for positive + infinity. Otherwise, if the argument is an integer or a floating point number, a floating point number with the same value (within Python's floating point |