Figure out how to provide programmatic usage from JavaScript

[rla]

Current Prolog WebAssembly examples use the SWI-Prolog Foreign Language Interface through the Emscripten cwrap function.

This has been separatedly done in each project. For example, in the prolog-vdom project:
https://github.com/rla/prolog-vdom/blob/23f85a6dbccefd189f4cff179106180e2f12234a/js/prolog.js

This code should probably be distributed together with the SWI WebAssembly version and with the source code. The list of functions used by this JavaScript bridge depend on the list of exported functions, specified during build process of the SWI WebAssembly version. Reference:
https://github.com/SWI-Prolog/swipl-devel/blob/7002bca038b5f20bbb42bb58ffccf4872060cb37/src/wasm/exports.json

There should be a small layer between cwrap'd C functions and actual SWI JavaScript API as some of the functions require C-style memory allocation through Emscripten before use. This layer is present in the prolog-vdom project.

[rla]

Related:

• Term representation (lazy JavaScript objects?).
• String encoding (wchar_t does not seem to be UTF32).
• Calling JavaScript from Prolog.

[rla]

The new term representation should also be ported to https://github.com/rla/node-swipl. That interface also has string encoding issues.