registerOperator, registerConstant

README.md

@@ -1,6 +1,7 @@
 Equation
 ========
 Solve math expressions or create equations for repeated and complex Math tasks.
+
 To use in browser, download [`equation.min.js`](https://raw.githubusercontent.com/mdibaiee/Equation.js/master/equation.min.js).
 
 ```javascript
@@ -13,6 +14,26 @@ let sphereArea = Equation.equation('4 * PI * r^2');
 console.log(sphereArea(5)); // 314.1592653589793
 ```
 
+You can also register your own operators and constants.
+
+```javascript
+// these options are explained below
+Equation.registerOperator('$', {
+  fn: a => 1/a,
+  format: '10',
+  precedence: 2
+});
+
+Equation.solve('$2'); // 0.5
+Equation.solve('$5'); // 0.2
+
+Equation.registerConstant('N', () => {
+  return Math.random() * 10 + 10
+});
+
+Equation.solve('N'); // a number between 10 and 20
+```
+
 API
 ===
 ####solve(expression: String)
@@ -22,6 +43,24 @@ Takes a math expression and evaluates it, returning the result.
 Takes a math expression containing variables, returning a function which
 replaces the variables with given arguments, and solves the expression.
 
+###registerOperator(key: String, options: Object)
+Registers a new operator.
+
+Options:
+
+#####fn
+  The function which runs on arguments
+#####format
+  The format which specifies how arguments are placed relative to operator, this is a string in which 1 indicates operator and zeroes indicate arguments.
+
+  For example `+` has the format `010` and factorial has `01`.
+#####precedence
+  Specifies the precedence of operator. The less the value, the higher the precedence, resulting in soon execution.
+
+###registerConstant(key: String, value: Function/Number)
+Registers a new constant. value can be a function (takes no arguments), or a constant number.
+
+That's right, we have named these *constants* but they actually can change, that's why we can use functions to define them. An example is the `RAND` constant which calls `Math.random`.
 TODO
 ====
 * Equation solver

dist/index.js

@@ -93,6 +93,13 @@ var Equation = {
 
       return Equation.solve(expression);
     };
+  },
+
+  registerOperator: function registerOperator(key, options) {
+    _operators2['default'][key] = options;
+  },
+  registerConstant: function registerConstant(key, options) {
+    _constants2['default'][key] = options;
   }
 };
 

equation.js

@@ -270,6 +270,13 @@ var Equation = {
 
       return Equation.solve(expression);
     };
+  },
+
+  registerOperator: function registerOperator(key, options) {
+    _operators2['default'][key] = options;
+  },
+  registerConstant: function registerConstant(key, options) {
+    _constants2['default'][key] = options;
   }
 };
 

lib/README.md

@@ -1,28 +0,0 @@
-Equation
-========
-Solve math expressions or create equations for repeated and complex Math tasks.
-To use in browser, download [`equation.min.js`](https://raw.githubusercontent.com/mdibaiee/Equation.js/master/equation.min.js).
-
-```javascript
-// solve
-console.log(Equation.solve('4 * lg(4) ^ 3')); // 32
-
-// equation
-let sphereArea = Equation.equation('4 * PI * r^2');
-
-console.log(sphereArea(5)); // 314.1592653589793
-```
-
-API
-===
-####solve(expression: String)
-Takes a math expression and evaluates it, returning the result.
-
-###equation(expression: String)
-Takes a math expression containing variables, returning a function which
-replaces the variables with given arguments, and solves the expression.
-
-TODO
-====
-* Equation solver
-* More tests

lib/index.js

@@ -67,6 +67,13 @@ let Equation = {
 
       return Equation.solve(expression);
     };
+  },
+
+  registerOperator(key, options) {
+    operators[key] = options;
+  },
+  registerConstant(key, options) {
+    constants[key] = options;
   }
 };