mathjs/lib/function/construction/complex.js

module.exports = function (math) {
  var util = require('../../util/index'),

      BigNumber = math.type.BigNumber,
      Complex = require('../../type/Complex'),
      collection = require('../../type/collection'),

      isCollection = collection.isCollection,
      isNumber = util.number.isNumber,
      isString = util.string.isString,
      isComplex = Complex.isComplex;

  /**
   * Create a complex value or convert a value to a complex value.
   *
   * Syntax:
   *
   *     math.complex()                           // creates a complex value with zero
   *                                              // as real and imaginary part.
   *     math.complex(re : number, im : string)   // creates a complex value with provided
   *                                              // values for real and imaginary part.
   *     math.complex(re : number)                // creates a complex value with provided
   *                                              // real value and zero imaginary part.
   *     math.complex(complex : Complex)          // clones the provided complex value.
   *     math.complex(arg : string)               // parses a string into a complex value.
   *     math.complex(array : Array)              // converts the elements of the array
   *                                              // or matrix element wise into a
   *                                              // complex value.
   *     math.complex({re: number, im: number})   // creates a complex value with provided
   *                                              // values for real an imaginary part.
   *     math.complex({r: number, phi: number})   // creates a complex value with provided
   *                                              // polar coordinates
   *
   * Examples:
   *
   *    var a = math.complex(3, -4);     // a = Complex 3 - 4i
   *    a.re = 5;                        // a = Complex 5 - 4i
   *    var i = a.im;                    // Number -4;
   *    var b = math.complex('2 + 6i');  // Complex 2 + 6i
   *    var c = math.complex();          // Complex 0 + 0i
   *    var d = math.add(a, b);          // Complex 5 + 2i
   *
   * See also:
   *
   *    bignumber, boolean, index, matrix, number, string, unit
   *
   * @param {* | Array | Matrix} [args]
   *            Arguments specifying the real and imaginary part of the complex number
   * @return {Complex | Array | Matrix} Returns a complex value
   */
  math.complex = function complex(args) {
    switch (arguments.length) {
      case 0:
        // no parameters. Set re and im zero
        return new Complex(0, 0);

      case 1:
        // parse string into a complex number
        var arg = arguments[0];

        if (isNumber(arg)) {
          return new Complex(arg, 0);
        }

        if (arg instanceof BigNumber) {
          // convert to Number
          return new Complex(arg.toNumber(), 0);
        }

        if (isComplex(arg)) {
          // create a clone
          return arg.clone();
        }

        if (isString(arg)) {
          var c = Complex.parse(arg);
          if (c) {
            return c;
          }
          else {
            throw new SyntaxError('String "' + arg + '" is no valid complex number');
          }
        }

        if (isCollection(arg)) {
          return collection.deepMap(arg, complex);
        }

        if (typeof arg === 'object') {
          if('re' in arg && 'im' in arg) {
            return new Complex(arg.re, arg.im);
          } else if ('r' in arg && 'phi' in arg) {
            return Complex.fromPolar(arg.r, arg.phi);
          }
        } 

        throw new TypeError('Two numbers, single string or an fitting object expected in function complex');

      case 2:
        // re and im provided
        var re = arguments[0],
            im = arguments[1];

        // convert re to number
        if (re instanceof BigNumber) {
          re = re.toNumber();
        }

        // convert im to number
        if (im instanceof BigNumber) {
          im = im.toNumber();
        }

        if (isNumber(re) && isNumber(im)) {
          return new Complex(re, im);
        }
        else {
          throw new TypeError('Two numbers or a single string expected in function complex');
        }

      default:
        throw new math.error.ArgumentsError('complex', arguments.length, 0, 2);
    }
  };
};