Implemented construction function number

HISTORY.md

@@ -10,6 +10,8 @@ https://github.com/josdejong/mathjs
   `scope`, similar to `parse`. Example: `math.eval('x^a', {x:3, a:2});`.
 - Implemented function `subset`, to get or set a subset from a matrix, string,
   or other data types.
+- Implemented construction functions number and string (mainly useful inside
+  the parser).
 - Improved function `det`. Thanks Bryan Cuccioli (bcuccioli).
 - Moved the parse code from prototype math.expr.Parser to function math.parse,
   simplified Parser a little bit.

README.md

@@ -538,6 +538,17 @@ types (Number, Complex, Unit, String, and Array) where applicable.
 - math.arg(x)
 - math.conj(x)
 
+### Construction
+
+- math.complex(re, im)
+- math.matrix(x)
+- math.number(x)
+- math.parser()
+- math.range(start [, step] , end)
+- math.string(x)
+- math.unit(x)
+- math.workspace()
+
 ### Matrix
 
 - math.concat(a, b, c, ... [, dim])

math.js

@@ -737,7 +737,7 @@ function Complex(re, im) {
 
     if ((re != null && !isNumber(re)) || (im != null && !isNumber(im))) {
         throw new TypeError(
-            'Two numbers or a single string expected in Complex constructor');
+            'Two numbers expected in Complex constructor');
     }
 
     this.re = re || 0;
@@ -6480,6 +6480,29 @@ math.matrix = function matrix(data) {
     return new Matrix(data);
 };
 
+/**
+ * Create a number or convert a string to a number
+ * @param {String | Number | Boolean} [value]
+ * @return {Number} num
+ */
+math.number = function (value) {
+    switch (arguments.length) {
+        case 0:
+            return 0;
+        case 1:
+            var num = Number(value);
+            if (isNaN(num)) {
+                num = Number(value.valueOf());
+            }
+            if (isNaN(num)) {
+                throw new SyntaxError(value.toString() + ' is no valid number');
+            }
+            return num;
+        default:
+            throw newArgumentsError('number', arguments.length, 0, 1);
+    }
+};
+
 /**
  * Create a parser. The function creates a new math.expr.Parser object.
  *

src/function/construction/number.js

@@ -0,0 +1,22 @@
+/**
+ * Create a number or convert a string to a number
+ * @param {String | Number | Boolean} [value]
+ * @return {Number} num
+ */
+math.number = function (value) {
+    switch (arguments.length) {
+        case 0:
+            return 0;
+        case 1:
+            var num = Number(value);
+            if (isNaN(num)) {
+                num = Number(value.valueOf());
+            }
+            if (isNaN(num)) {
+                throw new SyntaxError(value.toString() + ' is no valid number');
+            }
+            return num;
+        default:
+            throw newArgumentsError('number', arguments.length, 0, 1);
+    }
+};

src/type/Complex.js

@@ -25,7 +25,7 @@ function Complex(re, im) {
 
     if ((re != null && !isNumber(re)) || (im != null && !isNumber(im))) {
         throw new TypeError(
-            'Two numbers or a single string expected in Complex constructor');
+            'Two numbers expected in Complex constructor');
     }
 
     this.re = re || 0;

test/function/construction/number.js

@@ -0,0 +1,39 @@
+// test number construction
+var assert = require('assert'),
+    math = require('../../../math.js'),
+    approx = require('../../../tools/approx.js'),
+    number = math.number;
+
+// 0 arguments
+approx.equal(number(), 0);
+
+// 1 argument
+
+// boolean input
+approx.equal(number(true), 1);
+approx.equal(number(false), 0);
+
+// number input
+approx.equal(number(3), 3);
+approx.equal(number(-3), -3);
+
+// string input
+approx.equal(number('2.1e3'), 2100);
+approx.equal(number(' 2.1e-3 '), 0.0021);
+approx.equal(number(''), 0);
+approx.equal(number(' '), 0);
+assert.throws(function () {number('2.3.4')}, SyntaxError);
+assert.throws(function () {number('23a')}, SyntaxError);
+
+// wrong number of arguments
+assert.throws(function () {number(1,2)}, SyntaxError);
+assert.throws(function () {number(1,2,3)}, SyntaxError);
+
+// wrong type of arguments
+assert.throws(function () {number(math.complex(2,3))}, SyntaxError);
+assert.throws(function () {number(math.unit('5cm'))}, SyntaxError);
+assert.throws(function () {number(math.range(1,3))}, SyntaxError);
+assert.throws(function () {number(math.matrix([1,3]))}, SyntaxError);
+assert.throws(function () {number([1,3])}, SyntaxError);
+
+