JavaScript API

The npm package @tuprolog/arg2p exposes the engine through a single object, JsBridge. It takes the query, the theory and the flags as plain text, and returns the solutions together with the computed argumentation graph.

{
  "dependencies": {
    "@tuprolog/arg2p": "0.16.3"
  }
}

const arg2p = require('@tuprolog/arg2p').it.unibo.tuprolog.argumentation.bridge.JsBridge

The package @tuprolog/arg2p-causality-solver is published as well, but the causality predicates are already reachable through the bridge — see Causality.

`solve`

JsBridge.solve(query, theory, flags, outputConsumer)

Parameter	Meaning
`query`	The goal to run, e.g. `'arg2p::solve'` or `'arg2p::solve(d, Res)'`
`theory`	The theory, as Prolog text
`flags`	The flags, as Prolog facts
`outputConsumer`	A function receiving whatever the engine prints

Unlike the Kotlin API, the bridge does not fill in default flags: the flags string must declare every required one.

const result = arg2p.solve('arg2p::solve', `
    f1 :=> d.
    f2 :=> -d.`, `
    graphBuildMode(standard_af).
    statementLabellingMode(statement).
    argumentLabellingMode(grounded).
    orderingPrinciple(last).
    orderingComparator(elitist).
    graphExtension(standardPref).
    queryMode.`, out => console.log(out))

Reading the solutions

solve returns an object with an iterator i and the query that produced it. The iterator has hasNext() and next(), and next() throws once the solutions are exhausted:

const it = result.i

while (it.hasNext()) {
    const solution = it.next()
    console.log(solution.res)
}

Solution fields

Field	Content
`res`	`'yes'`, `'no'` or `'halt'`
`query`	The query this solution answers
`substitutions`	An array of `{ first, second }` pairs: variable name and its value
`exception`	The error message, when the engine raised one
`graph`	The argumentation graph computed for this solution

Graph fields

solution.graph has two arrays:

Field	Content
`arguments`	Objects with `id`, `descriptor` and `label` (`in`, `out`, `und`)
`attacks`	Objects with `from` and `to`, the ids of the two arguments

const graph = result.i.next().graph

graph.arguments.forEach(arg => console.log(`${arg.label} : ${arg.descriptor}`))
graph.attacks.forEach(att => console.log(`${att.from} attacks ${att.to}`))

Querying a single goal

const solution = arg2p.solve('arg2p::solve(d, Res)', theory, flags, _ => { }).i.next()

solution.substitutions.forEach(s => console.log(`${s.first} = ${s.second}`))

Full example

A complete browser application built on this bridge — the Web Playground — is available at tuprolog/arg2p-kt-web, and runs online here.