swahili-lang/bin/interpreter/types/built-in-function.js

A new programming language with semantics borrowed from the Swahili language to help teach programming concepts to Swahili speaking students.

const util = require('util');
const colors = require('colors');

const SWBaseFunction = require('./base-function');
const RTResult = require('../runtimeResult');
const { functions } = require('../lib');

/** Built in function data type */
class SWBuiltInFunction extends SWBaseFunction {
  /**
   * instantiates a built in function
   * @param {String} name the name of the built in function
   */
  constructor(name) {
    super(name);

    // library injection
    const fn = functions.find((f) => f.method.name === name);
    if (fn) {
      const { method, args, types = null } = fn;
      this[name] = method;
      this.args = args;
      if (types) this.types = types;
    }
  }

  /**
   * Executes the function
   * @param {Token[]} args list of token value nodes to be used as function arguments
   */
  execute(args) {
    let res = new RTResult();
    let executionContext = this.generateNewContext();

    let method = this[this.name] || this.noExecuteMethod;
    let argNames = this.args;

    res.register(this.populateArgs(argNames, args, executionContext));
    if (res.shouldReturn()) return res;

    let returnValue = res.register(method(this, executionContext));
    if (res.shouldReturn()) return res;
    return res.success(returnValue);
  }

  /**
   * Occurs when no execution method is defined for the built in function
   * @param {Node} node the AST node to visit
   * @param {Context} context the calling context
   */
  noExecuteMethod = (node, context) => {
    throw new Error(`No ${node.constructor.name} method defined`);
  };

  /**
   * creates a new instance of the function
   * @returns {SWBuiltInFunction}
   */
  copy() {
    let copy = new SWBuiltInFunction(this.name);
    copy.args = this.args;
    copy.name = this.name;
    copy.types = this.types;
    copy[this.name] = this[this.name];
    copy.setPosition(this.posStart, this.posEnd);
    copy.setContext(this.context);
    return copy;
  }

  [util.inspect.custom](depth, options) {
    return this.toString();
  }

  /**
   * string representation of the function class
   * @param {Boolean} format whether to format the name or not
   * @returns {String}
   */
  toString(format = true) {
    return format
      ? colors.brightCyan(`<shughuli asili ${this.name}>`)
      : this.name;
  }
}

module.exports = SWBuiltInFunction;