New feature non-decimal integer literals (SQL:2023 T661) and underscores in numeric literals (SQL:2023 T662)

doc/sql.extensions/README.decimal_and_non_decimal_literals.txt

@@ -0,0 +1,131 @@
+=============================================
+Decimal integer literals
+Non-decimal integer literals (SQ:2023 T661)
+Underscores in numeric literals (SQ:2023 T662)
+==============================================
+
+Supports unsigned hexadecimal integers, unsigned octal integers, and unsigned binary integers.
+Also support for underscores in numeric and non-decimal literals
+
+Authors:
+    Alexey Chudaykin <[email protected]>
+
+Syntax rules:
+
+<plus sign> ::=
+    + !! U+002B
+
+<minus sign> ::=
+    - !! U+002D
+
+<period> ::=
+    . !! U+002E
+
+<underscore> ::=
+    _ !! U+005F
+
+<hexit> ::=
+    0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | A | B | C | D | E | F | a | b | c | d | e | f
+
+<octal digit> ::=
+    0 | 1 | 2 | 3 | 4 | 5 | 6 | 7
+
+<binary digit> ::=
+    0 | 1
+
+<signed numeric literal> ::=
+    [ <sign> ] <unsigned numeric literal>
+
+<unsigned numeric literal> ::=
+    <exact numeric literal> | <approximate numeric literal>
+
+<exact numeric literal> ::=
+    <unsigned integer> | <unsigned decimal integer> <period> [ <unsigned decimal integer> ] |
+        <period> <unsigned decimal integer>
+
+<sign> ::=
+    <plus sign> | <minus sign>
+
+<approximate numeric literal> ::=
+    <mantissa> E <exponent>
+
+<mantissa> ::=
+    <exact numeric literal>
+
+<exponent> ::=
+    <signed decimal integer>
+
+<signed integer> ::=
+    [ <sign> ] <unsigned integer>
+
+<signed decimal integer> ::=
+    [ <sign> ] <unsigned decimal integer>
+
+<unsigned integer> ::=
+    <unsigned decimal integer> | <unsigned hexadecimal integer> | <unsigned octal integer> |
+        <unsigned binary integer>
+
+<unsigned decimal integer> ::=
+    <digit> [ { [ <underscore> ] <digit> }... ]
+
+<unsigned hexadecimal integer> ::=
+    0X { [ <underscore> ] <hexit> }...
+
+<unsigned octal integer> ::=
+    0O { [ <underscore> ] <octal digit> }...
+
+<unsigned binary integer> ::=
+    0B { [ <underscore> ] <binary digit> }...
+
+Notes (non-decimal integer literals):
+    1. The standard allows non-decimal literals in the mantissa of an exponential number entry.
+       For example (0xAAAe10), but there may be a conflict (0xEEE10). Therefore, a restriction on
+       the use of non-decimal literals in the exponential number record is introduced.
+    2. The <unsigned hexadecimal integer> value is a numeric value defined by applying the usual
+       mathematical interpretation of positional hexadecimal notation to a string that is an
+       unsigned hexadecimal integer. Similarly for an unsigned octal integer and an
+       unsigned binary integer.
+    3. To represent negative values, place a minus sign in front of an unsigned hexadecimal literal.
+       Similarly for an unsigned octal integer and an unsigned binary integer. Similarly for an
+       unsigned octal integer and an unsigned binary integer.
+    4. Numbers with type SMALLINT cannot be written in hexadecimal, strictly speaking,
+       since even 0x1 evaluates to INTEGER. However, if you write a positive integer within
+       the 16-bit range 0x0000 (decimal zero) to 0x7FFF (decimal 32767), it will be converted to
+       SMALLINT transparently. Similarly for an unsigned octal integer and an
+       unsigned binary integer.
+
+Notes (underscores in numeric literals):
+    1. Limitations for non-decimal integer literals:
+        1.1. It is considered unacceptable for there to be two or more consecutive underscores;
+        1.2. Underscores are not allowed after the last character.
+    2. Limitations for decimal integer literals:
+        1.1. Underscores before the first character and after the last character are not allowed;
+        1.2. Underscores are not permitted before or after the <period> symbol;
+        1.3. Underscores are not allowed before or after the <E> character;
+        1.4. Underscores are not allowed after the last character.
+
+Examples (non-decimal integer literals):
+    1. Unsigned binary integer:
+        1.1. select  0b11010100, 0B11010100 from rdb$database;  --> 212;
+        1.2. select  0b0000000  from rdb$database;  --> 0;
+        1.3. select  -0b11010100, -0B11010100 from rdb$database; --> -212.
+    2. Unsigned octal intege:
+        2.1. select  0o12345670, 0O12345670 from rdb$database; --> 2739128;
+        2.2. select  0o00000000 from rdb$database; --> 0;
+        2.3. select  -0o12345670, -0O12345670 from rdb$database;   --> -2739128.
+    3. Unsigned hexadecimal integer:
+        3.1. select  0xABC123, 0XABC123 from rdb$database; --> 11256099;
+        3.2. select  0x00000000 from rdb$database; --> 0;
+        3.3. select  -0xABC123, -0XABC123 from rdb$database;   --> -11256099.
+        3.4. select 0x7FFFFFFFFF from rdb$database; -->  2147483647 type INTEGER
+        3.5. select 0x80000000 from rdb$database; -->  2147483648 type BIGINT
+        3.5. select 0x7FFFFFFFFFFFFFFF from rdb$database; -->  9223372036854775807 type BIGINT
+        3.6. select 0x8000000000000000 from rdb$database; -->  9223372036854775808 type INT128
+
+Examples (underscores in numeric literals):
+    1. For non-decimal integer literals:
+        1.1 Permitted: select 0x_FFFF, 0xFF_FF, 0x_FF_FF, 0x_FF_FF from rdb$database;
+        1.2 Forbidden: select 0x_FF__FF, 0xFFFFFF_, 0x_FF_FF_FF_ from rdb$database;
+    2. For decimal integer literals:
+        2.1 Permitted: select 10_10, 10_10.10_10, 10.10E-10_0 from rdb$database;
+        2.2 Forbidden: select _1010, 100_, 1010._1010, 1010_.1, 10.10E_-100_ from rdb$database;

doc/sql.extensions/README.hex_literals.txt

@@ -7,6 +7,7 @@ Support for hexadecimal numeric and binary string literals.
 Authors:
     Bill Oliver <[email protected]>
     Adriano dos Santos Fernandes <[email protected]>
+    Alexey Chudaykin <[email protected]>
 
 Syntax:
 
@@ -35,3 +36,8 @@ Notes (binary string literal):
 Example:
     select 0x10, cast('0x0F0000000' as bigint) from rdb$database;
     select x'deadbeef' from rdb$database;
+
+Notes by Alexey Chudaykin:
+    ISO/IEC 9075-2:2023(E) introduces rules for hexadecimal numbers, so this document should be
+    considered obsolete in the <numeric hex literal> part. Refer to the new document
+    README.decimal_and_non_decimal_literals.