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Issue #26331: Implement the parsing part of PEP 515.

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Thanks to Georg Brandl for the patch.
This commit is contained in:
Brett Cannon 2016-09-09 14:57:09 -07:00
parent ee73a65745
commit a721abac29
22 changed files with 743 additions and 205 deletions
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45
Doc/reference/lexical_analysis.rst
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@ -721,20 +721,24 @@ Integer literals
Integer literals are described by the following lexical definitions:
.. productionlist::
integer: `decimalinteger` | `octinteger` | `hexinteger` | `bininteger`
decimalinteger: `nonzerodigit` `digit`* | "0"+
integer: `decinteger` | `bininteger` | `octinteger` | `hexinteger`
decinteger: `nonzerodigit` (["_"] `digit`)* | "0"+ (["_"] "0")*
bininteger: "0" ("b" | "B") (["_"] `bindigit`)+
octinteger: "0" ("o" | "O") (["_"] `octdigit`)+
hexinteger: "0" ("x" | "X") (["_"] `hexdigit`)+
nonzerodigit: "1"..."9"
digit: "0"..."9"
octinteger: "0" ("o" | "O") `octdigit`+
hexinteger: "0" ("x" | "X") `hexdigit`+
bininteger: "0" ("b" | "B") `bindigit`+
bindigit: "0" | "1"
octdigit: "0"..."7"
hexdigit: `digit` | "a"..."f" | "A"..."F"
bindigit: "0" | "1"
There is no limit for the length of integer literals apart from what can be
stored in available memory.
Underscores are ignored for determining the numeric value of the literal. They
can be used to group digits for enhanced readability. One underscore can occur
between digits, and after base specifiers like ``0x``.
Note that leading zeros in a non-zero decimal number are not allowed. This is
for disambiguation with C-style octal literals, which Python used before version
3.0.
@ -743,6 +747,10 @@ Some examples of integer literals::
7 2147483647 0o177 0b100110111
3 79228162514264337593543950336 0o377 0xdeadbeef
100_000_000_000 0b_1110_0101
.. versionchanged:: 3.6
Underscores are now allowed for grouping purposes in literals.
.. _floating:
@ -754,23 +762,28 @@ Floating point literals are described by the following lexical definitions:
.. productionlist::
floatnumber: `pointfloat` | `exponentfloat`
pointfloat: [`intpart`] `fraction` | `intpart` "."
exponentfloat: (`intpart` | `pointfloat`) `exponent`
intpart: `digit`+
fraction: "." `digit`+
exponent: ("e" | "E") ["+" | "-"] `digit`+
pointfloat: [`digitpart`] `fraction` | `digitpart` "."
exponentfloat: (`digitpart` | `pointfloat`) `exponent`
digitpart: `digit` (["_"] `digit`)*
fraction: "." `digitpart`
exponent: ("e" | "E") ["+" | "-"] `digitpart`
Note that the integer and exponent parts are always interpreted using radix 10.
For example, ``077e010`` is legal, and denotes the same number as ``77e10``. The
allowed range of floating point literals is implementation-dependent. Some
examples of floating point literals::
allowed range of floating point literals is implementation-dependent. As in
integer literals, underscores are supported for digit grouping.
3.14 10. .001 1e100 3.14e-10 0e0
Some examples of floating point literals::
3.14 10. .001 1e100 3.14e-10 0e0 3.14_15_93
Note that numeric literals do not include a sign; a phrase like ``-1`` is
actually an expression composed of the unary operator ``-`` and the literal
``1``.
.. versionchanged:: 3.6
Underscores are now allowed for grouping purposes in literals.
.. _imaginary:
@ -780,7 +793,7 @@ Imaginary literals
Imaginary literals are described by the following lexical definitions:
.. productionlist::
imagnumber: (`floatnumber` | `intpart`) ("j" | "J")
imagnumber: (`floatnumber` | `digitpart`) ("j" | "J")
An imaginary literal yields a complex number with a real part of 0.0. Complex
numbers are represented as a pair of floating point numbers and have the same
@ -788,7 +801,7 @@ restrictions on their range. To create a complex number with a nonzero real
part, add a floating point number to it, e.g., ``(3+4j)``. Some examples of
imaginary literals::
3.14j 10.j 10j .001j 1e100j 3.14e-10j
3.14j 10.j 10j .001j 1e100j 3.14e-10j 3.14_15_93j
.. _operators: