Formatting Output with Prolog
The nonterminal format_//2 lets us conveniently describe formatted strings and tables with Prolog. It is provided by library(format) in several modern Prolog systems such as Scryer, Tau and Trealla Prolog. The library is in the public domain, and you can freely include it in your Prolog systems and applications. It is best used together with library(pio) and its predicates for pure output, combining declarative descriptions with efficient writing of characters to streams.