Manages the Clingo dependency and wraps it with a useful API with TypeScript support.

Currently in the very early prototyping stage.

• Make the usage of this package as simple as adding and importing import {runClingo} from "clingo-wrapper";. We shouldn't need to add polyfill dependencies and put so much into the webpack.config.js file.
• Create a build script that will transpile this package's TypeScript source to Javascript and other necessary files.
• Ideally, find out how to compile Clingo to files that don't require modification or hacky fixes to work work Webpack.
• Create a Clingo compile script that will automatically clone and appropriately compile Clingo from source and insert it into this package's source.
• Figure out how to make this package work outside of the very narrow use-case of being imported into web application code with Webpack and using TypeScript.

This package is currently only set up to work as an import for web application code bundled using Webpack, requiring TypeScript to be set up. It could very well work in other contexts, but it's currently untested.

To use it, begin by importing clingo-wrapper and using it in your web application code:

import {runClingo} from "clingo-wrapper";

const query = `
base(colour, blue).
base(colour, red).
base(colour, green).

base(vertex, v1).
base(vertex, v2).
base(vertex, v3).
base(vertex, v4).

instance(edge(v1, v2)).
instance(edge(v2, v3)).
instance(edge(v3, v4)).
instance(edge(v4, v1)).
instance(edge(v1, v3)).

{ solution(color(V,C)) } :- base(vertex, V), base(colour, C).
coloured(V) :- solution(color(V,C)).
:- base(vertex, V), not coloured(V).
:- solution(color(V,C1)), solution(color(V,C2)), C1 != C2.
:- instance(edge(V1, V2)), solution(color(V1, C)), solution(color(V2, C)).
#show.
#show X : solution(X).
`;

const result = await runClingo(query);
console.log(result);

Next, you'll need to add polyfill dependencies:

$ yarn add buffer crypto-browserify events path-browserify stream-browserify string_decoder

And modify webpack.config.js by adding the equivalent of the following:

module.exports = {
    resolve: {
        fallback: {
            "buffer": require.resolve("buffer/"),
            "crypto": require.resolve("crypto-browserify"),
            "events": require.resolve("events/"),
            "path": require.resolve("path-browserify"),
            "stream": require.resolve("stream-browserify"),
            "string_decoder": require.resolve("string_decoder/"),
        },
    },
    module: {
        rules: [
            {test: /\.wasm$/i, type: "asset/resource"},
        ],
    },
};

To compile Clingo, download the latest release from GitHub and extract the archive.

We will then follow the instructions from clingo's INSTALL.md, except we must also add -s MODULARIZE=1 to DCMAKE_CXX_FLAGS. The exact commands that worked for me were:

$ cd clingo-5.5.1
$ emcmake cmake -H. -Bbuild \
    -DCLINGO_BUILD_WEB=On \
    -DCLINGO_BUILD_WITH_PYTHON=Off \
    -DCLINGO_BUILD_WITH_LUA=Off \
    -DCLINGO_BUILD_SHARED=Off \
    -DCLASP_BUILD_WITH_THREADS=Off \
    -DCMAKE_VERBOSE_MAKEFILE=On \
    -DCMAKE_BUILD_TYPE=release \
    -DCMAKE_CXX_FLAGS="-std=c++11 -Wall -s DISABLE_EXCEPTION_CATCHING=0 -s MODULARIZE=1" \
    -DCMAKE_CXX_FLAGS_RELEASE="-Os -DNDEBUG" \
    -DCMAKE_EXE_LINKER_FLAGS="" \
    -DCMAKE_EXE_LINKER_FLAGS_RELEASE=""
$ cmake --build build --target web

The compiled files clingo.js and clingo.wasm should now be present in ./build/bin. Copy both files to ./src/compiled-files (replacing the existing files).

After copying, you'll need to make some minor modifications to clingo.js. This is because by default, Emscripten will attempt to access /clingo.wasm. First, we need to add the following lines to the top of the script (comment's optional, but helpful):

const __clingoWASM_importByHand_full = require("./clingo.wasm");
// Extract pathname and remove leading slash
const __clingoWASM_importByHand_modified = (new URL(__clingoWASM_importByHand_full)).pathname.substring(1);

Then, search for the string "clingo.wasm" in the file and replace it with __clingoWASM_importByHand_modified.

This package is licensed under the MIT License (MIT).

This repository contains a compiled copy of Clingo. Clingo is licensed under the MIT license. A copy of the license can be found in clingo-wrapper/LICENSE.clingo.md.

Additional software packages are used and managed through the yarn package manager.