tom-weatherhead/thaw-grammar

// tom-weatherhead/thaw-grammar/src/languages/prolog/utilities.ts

import { createSet, IImmutableSet } from 'thaw-common-utilities.ts';

import { PrologFunctorExpression } from './domain-object-model/prolog-functor-expression';
import { PrologGoal } from './domain-object-model/prolog-goal';
import { createPrologVariable } from './domain-object-model/prolog-variable';

import { ISubstitution } from './domain-object-model/interfaces/isubstitution';
import { IPrologVariable } from './domain-object-model/interfaces/ivariable';

export function createGoalFromFunctorExpression(fe: PrologFunctorExpression): PrologGoal {
    return new PrologGoal(fe.gs, fe.Name, fe.ExpressionList);
}

export function createFunctorExpressionFromGoal(goal: PrologGoal): PrologFunctorExpression {
    return new PrologFunctorExpression(goal.gs, goal.Name, goal.ExpressionList);
}

// UUIDs: Use the npm module 'uuid' instead of the code below.

// From https://stackoverflow.com/questions/105034/how-to-create-a-guid-uuid :

// export function uuidv4(): string {
//     return ([1e7]+-1e3+-4e3+-8e3+-1e11).replace(/[018]/g, c =>
//         (c ^ crypto.getRandomValues(new Uint8Array(1))[0] & 15 >> c / 4).toString(16)
//     );
// }

// **** BEGIN Utilities for substitutions ****
// Placed here to avoid a circular reference between prolog-substitution.js and prolog-variable.js

// public ContainsOnlyVariables(): boolean {
//     return Array.from(this.SubstitutionList.values()).every(
//         (v: IPrologExpression) => isIVariable(v)
//     );
// }

export function findBindingVariablesInSubstitution(
    s: ISubstitution
): IImmutableSet<IPrologVariable> {
    const result = createSet<IPrologVariable>();

    for (const key of s.SubstitutionList.keys()) {
        result.add(createPrologVariable(key));

        const v = s.SubstitutionList.get(key);

        if (typeof v !== 'undefined') {
            result.unionInPlace(v.FindBindingVariables());
        }
    }

    return result;
}

// public get IsOneToOne(): boolean {
//     const values: PrologVariable[] = [];

//     for (const value of this.SubstitutionList.values()) {
//         const vv = value as PrologVariable;

//         if (typeof vv === 'undefined') {
//             return false;
//         }

//         values.push(vv);
//     }

//     return values.length === Array.from(this.SubstitutionList.keys()).length;
// }

// **** END Utilities for substitutions ****