database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-28 23:42:10 +03:00
Code Activity

Allow underscores in integer and numeric constants.

Browse Source 
This allows underscores to be used in integer and numeric literals,
and their corresponding type input functions, for visual grouping.
For example:

    1_500_000_000
    3.14159_26535_89793
    0xffff_ffff
    0b_1001_0001

A single underscore is allowed between any 2 digits, or immediately
after the base prefix indicator of non-decimal integers, per SQL:202x
draft.

Peter Eisentraut and Dean Rasheed

Discussion: https://postgr.es/m/84aae844-dc55-a4be-86d9-4f0fa405cc97%40enterprisedb.com
This commit is contained in:
Dean Rasheed
2023-02-04 09:48:51 +00:00
parent 1b6f632a35
commit faff8f8e47
22 changed files with 712 additions and 172 deletions
Download Patch File Download Diff File Expand all files Collapse all files

36
doc/src/sgml/syntax.sgml
View File

@ -677,7 +677,8 @@ $function$
decimal point, if one is used. At least one digit must follow the
exponent marker (<literal>e</literal>), if one is present.
There cannot be any spaces or other characters embedded in the
constant. Note that any leading plus or minus sign is not actually
constant, except for underscores, which can be used for visual grouping as
described below. Note that any leading plus or minus sign is not actually
considered part of the constant; it is an operator applied to the
constant.
</para>
@ -695,23 +696,24 @@ $function$
</para>
<para>
Additionally, non-decimal integer constants can be used in these forms:
Additionally, non-decimal integer constants are accepted in these forms:
<synopsis>
0x<replaceable>hexdigits</replaceable>
0o<replaceable>octdigits</replaceable>
0b<replaceable>bindigits</replaceable>
</synopsis>
<replaceable>hexdigits</replaceable> is one or more hexadecimal digits
where <replaceable>hexdigits</replaceable> is one or more hexadecimal digits
(0-9, A-F), <replaceable>octdigits</replaceable> is one or more octal
digits (0-7), <replaceable>bindigits</replaceable> is one or more binary
digits (0-7), and <replaceable>bindigits</replaceable> is one or more binary
digits (0 or 1). Hexadecimal digits and the radix prefixes can be in
upper or lower case. Note that only integers can have non-decimal forms,
not numbers with fractional parts.
</para>
<para>
These are some examples of this:
<literallayout>0b100101
These are some examples of valid non-decimal integer constants:
<literallayout>
0b100101
0B10011001
0o273
0O755
@ -720,13 +722,21 @@ $function$
</literallayout>
</para>
<note>
<para>
Non-decimal integer constants are currently only supported in the range
of the <type>bigint</type> type (see <xref
linkend="datatype-numeric-table"/>).
</para>
</note>
<para>
For visual grouping, underscores can be inserted between digits. These
have no further effect on the value of the constant. For example:
<literallayout>
1_500_000_000
0b10001000_00000000
0o_1_755
0xFFFF_FFFF
1.618_034
</literallayout>
Underscores are not allowed at the start or end of a numeric constant or
a group of digits (that is, immediately before or after the decimal point
or the exponent marker), and more than one underscore in a row is not
allowed.
</para>
<para>
<indexterm><primary>integer</primary></indexterm>