InterpretProgram

Interpret.ts

function interpret(pgm: any): any {
  let isArray = Array.isArray(pgm);
  if (isArray) {
    let program = pgm as any[];
    switch (program[0]) {
      case 'if': {
        let condition: boolean = interpret(program[1]);
        let trueValue = interpret(program[2]);
        let falseValue = interpret(program[3]);
        return condition ? trueValue : falseValue;
      }
      case 'gt': {
        let a = interpret(program[1]) as number;
        let b = interpret(program[2]) as number;
        return a > b;
      }
      case 'lt': {
        let a = interpret(program[1]) as number;
        let b = interpret(program[2]) as number;
        return a < b;
      }
      case 'eq': {
        let a = interpret(program[1]) as number;
        let b = interpret(program[2]) as number;
        return a === b;
      }
      // operators
      default: {
        return handleOperators(program) as any;
      }
    }
  } else {
    return pgm;
  }
}

let handleOperators = (program: any[]): number => {
  let a = interpret(program[1]) as number;
  let b = interpret(program[2]) as number;
  let operator = program[0];
  switch (operator) {
    case 'add': {
      return a + b;
    }
    case 'sub': {
      return a - b;
    }
    case 'mul': {
      return a * b;
    }
    case 'div': {
      return a / b;
    }
    default: {
      return 0;
    }
  }
};