Baseprefixed

Baseprefixed refers to a style of representing numeric literals in source code where a prefix indicates the number’s base or radix. In baseprefixed notation, the prefix is used to disambiguate the numeral’s base so that the value can be parsed unambiguously by a compiler or interpreter. The concept is common across many programming languages and data formats, though the exact prefixes and rules vary.

Common prefixes include 0x for hexadecimal, 0b for binary, and 0o for octal in languages such as JavaScript and Python. Decimal numbers typically require no prefix. For example, 0x2A represents the hexadecimal value 2A, 0b1010 represents binary ten, and 0o77 represents octal sixty-seven. Some languages also accept uppercase prefixes (0X, 0B, 0O) and have rules about digit case in the numeral itself.

Language-specific variations exist. Some environments historically treated numbers with leading zeros as octal, which could cause confusion or errors when porting code between languages. Others enforce strict syntax for octal or binary literals, or restrict certain bases to particular contexts. In modern languages, baseprefixed literals are often used in conjunction with integer types, bitwise operations, and low-level programming tasks where precise control over the numeric representation is important.

Limitations and pitfalls include portability concerns, readability for those unfamiliar with a language’s prefixes, and the need to remember the exact prefix set for a given language. Good practice typically involves using baseprefixed literals when they clearly convey meaning (e.g., hexadecimal color codes or bit masks) and avoiding ambiguity in mixed-base expressions. See also numeral systems, radix, and number literals.