Printconst

Printconst is a term used in programming literature to refer to a mechanism that outputs the textual representation of a constant value. Depending on the language, printconst may be implemented as a function, a macro, or a compile-time directive designed to reveal the value and form of a constant without evaluating non-constant expressions.

Common goals include debugging, diagnostics, and educational demonstrations of constant expressions. When implemented as a compile-time facility, printconst can embed the literal form of a constant into generated code or logs, sometimes preserving type qualifiers, suffixes, or base representations (such as decimal, hex, or binary). As a runtime function, it may receive a constant value and return a string that represents the value in a stable format.

Different languages implement printconst in different ways. In macro-rich languages, a printconst-like macro might stringify its argument, printing the source code the constant was written as. In languages with rich type systems, a dedicated intrinsic or standard library function might print the value while maintaining type information for subsequent formatting.

Limitations include the fact that not all constants can be fully represented as strings, potential loss of precision for large numbers, and portability concerns across locales and platforms. Careful use is advised to avoid confusing outputs, and to ensure that printing constants does not introduce side effects if the constant is part of a larger expression. See also constants, stringification, and compile-time evaluation.