13.33.1 New Features

• The Unicode 15 standard is now used to classify which characters can occur in single-quoted atoms and double quoted lists.

  This means that certain characters, like emoticons, can occur as themselves in quoted atoms without the need for \x...\-style quoting. This change does not affect the characters that can occur in unquoted contexts, like unquoted atoms, variables and numbers.

• The JSON-RPC server for communicating with other programming languages has been promoted to a supported library. An early version was present as example code in some earlier releases.

  The library comes with simple examples that use JSON data for communicating between clients, written in several different programming languages, and SICStus. Example clients are provided in Python, Java, C#, C, Go, and Prolog.

  It also comes with a more interesting example where the client, which can be written in any programming language, uses the Prolog server to maintain a collection of constrained (using library(clpfd)) variables. This example showcases an easy way to expose SICStus’ award-winning constraint engine to clients written in other languages.

  See JSON mediated process communication in the SICStus Prolog Manual and Simpler use of JSON mediated process communication in the SICStus Prolog Manual, for details and examples.

  The new code, library('jsonrpc/jsonrpc_server') and library('jsonrpc/simple_jsonrpc_server'), is similar to, but not directly compatible with, the example code in earlier releases.

• CLPFD:
  • - Expression if_then_else/3 and constraint if_then_else/4 are new.
  • - Performance improvements of the propagation mechanism and of several frequently used constraints.