LastIndexOfconst

LastIndexOfconst is a term used in discussions of string processing APIs to denote a variant of the conventional lastIndexOf operation that is restricted to constant expressions. It is not a standard built-in function in major languages, but rather a concept proposed to enable compile-time evaluation of string searches when both the source text and the pattern are constants. The goal is to allow static analysis, optimization, or code generation by resolving the result at compile time whenever possible.

Semantics and typical signature. A lastIndexOfconst function returns the zero-based index of the last occurrence of a pattern within a given string, or -1 if the pattern does not occur. The “const” aspect implies that the arguments should be constant expressions. In languages that support constexpr, consteval, or equivalent compile-time evaluation, lastIndexOfconst would be evaluable entirely at compile time if the inputs are literals. Some designs distinguish between substring searches and single-character searches and may include optional parameters such as a starting position.

Language considerations. In C++, lastIndexOfconst could be realized as a constexpr or consteval function operating on string literals or std::array<char, N> data, allowing compile-time constant results. In dynamically typed languages like JavaScript, a conceptual lastIndexOfconst would resemble a normal lastIndexOf but restricted by a compile-time evaluation policy implemented via language tooling rather than the language itself. Practical implementations would need to address encoding, multibyte characters, and end-of-string conditions.

See also. lastIndexOf, rfind, constexpr, static analysis.