XLLong

XLLong is a hypothetical data type and accompanying software library designed to illustrate how 64-bit integers could be integrated into spreadsheet environments that traditionally rely on floating-point numbers. The concept envisions an extension to the Excel add-in model (an XLL-style interface) that exposes a dedicated 64-bit signed integer type, along with functions for creation, conversion, arithmetic, and comparison. XLLong values would be stored in a way that preserves exact integer precision, avoiding the rounding behavior typical of 64-bit floating point numbers when representing large integers.

In typical design sketches, XLLong would include API bindings for C, C++, and .NET languages, enabling users to bring 64-bit integer data into worksheets, formulas, and scripts. It would also provide interoperability with external data sources, serialization formats, and potential integration with existing UDFs. Key considerations discussed in its theoretical treatment include overflow detection, range checks, endianness, and performance for bulk operations on large arrays of values. Licensing and governance of real-world implementations would vary, with possible permissive open-source licenses or educational licenses in early stages.

Critiques in the fictional discourse focus on the complexity of extending spreadsheet data models, potential compatibility issues with existing functions, and the risk of confusing users who expect standard floating-point behavior. See also 64-bit integers, Excel add-ins, and arbitrary-precision libraries.