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Specifications
Literals are values given explicitly in the source code.
All integer numeric literals may have any number of underscore characters (_) in them to space out the digits. The only exception is that the underscore may not be the first character of the literal.[1]
Decimal integers are denoted as a sequence of one or more decimal digits (in the range 0-9) or the underscore character. The first character of the literal may not be an underscore. The first character of the literal may only be the digit 0 if the literal contains no more digits[2].
Hexadecimal integers start with 0x or 0X, followed by one or more hexadecimal digits (0-9 or a-f in either cases). The digits MAY have any number of underscores between them, but MAY NOT begin with an underscore or have an underscore between the leading 0 and the x.
All of the following are legal hexadecimal literals:
- 0x0
- 0x___12
- 0xA
- 0X12_
- 0x___ (no digits)
- _0x12 (a legal identifier)
- 0_x12 (underscore between 0 and x)
- 0xcovfefe ("o" and "v" are not hexadecimal digits).
Binary integers start with 0b or 0B, followed by one or more binary digits (0 or 1). The digits MAY have any number of underscores between them, but the literal MAY NOT begin with an underscore or have an underscore between the leading 0 and the b.
All of the following are legal binary literals:
- 0b0
- 0b_0010_1101__1011_1000
- 0b10_
- 0b___ (no digits)
- _0b11 (a legal identifier)
- 0_b11 (underscore between 0 and b)
- 0b12 (2 is not a binary digit)
Practical has no octal literal integers built into the language's syntax. A TBD library function will be used to specify octal literals.
TBD
TBD
This section was moved to the official language specs.
- ^ Otherwise it is not possible to know whether this is an integer literal or an identifier.
- ^ This is done to avoid confusion with C's octal literals.