tom-weatherhead/thaw-grammar

// tom-weatherhead/thaw-grammar/src/common/domain-object-model/function-definition.ts

import { Name } from 'thaw-interpreter-core';

import { IEnvironmentFrame } from './environment-frame';
import { IExpression } from './iexpression';
import { IGlobalInfo } from './iglobal-info';
import { IVariable } from './variable';

const typenameFunctionDefinition = 'FunctionDefinition';

export function isFunctionDefinition<T>(obj: unknown): obj is FunctionDefinition<T> {
    const str = obj as FunctionDefinition<T>;

    return typeof str !== 'undefined' && str.typename === typenameFunctionDefinition;
}

export interface IFunctionDefinition<T> extends IExpression<T> {
    readonly functionName: Name;
    readonly argList: IVariable<T>[];
    readonly body: IExpression<T>;
}

export class FunctionDefinition<T> implements IFunctionDefinition<T> {
    public readonly typename: string = typenameFunctionDefinition;

    constructor(
        public readonly functionName: Name,
        public readonly argList: IVariable<T>[],
        public readonly body: IExpression<T>
    ) {}

    public toString(): string {
        return `(define ${this.functionName} ${this.argList} ${this.body})`;
    }

    public evaluate(
        globalInfo: IGlobalInfo<T>,
        // eslint-disable-next-line @typescript-eslint/no-unused-vars
        localEnvironment?: IEnvironmentFrame<T>,
        // eslint-disable-next-line @typescript-eslint/no-unused-vars
        options?: unknown
    ): T {
        globalInfo.functionDefinitions.set(this.functionName.value, this);

        return globalInfo.trueValue;
    }
}