ExpressionParser

Parametrized expression parser written for being used as a module in a larger applications for studying purposes.

1. It processes a string like cos(x) * 3+2 * sin(y)/5 or max(a * a,b * b,c * c) - 12 * a * b * c into an Expression class object, which can calculate value of the expression for any parameters x and y;
2. It finds errors in an input and throws an exception which often contains exact coordinates of the error;
3. It is parametrized with 4 developer defined sets of mathematical actions: functions and infix, prefix and postfix operations;
4. It is almost completely covered with JUnit tests.

User instructions:

1. Use InfixOperation, PrefixOperation, PostfixOperation and Function abstract classes for implementation of your own actions:

   1.1. zero argument functions are allowed;
   1.2. priority of any infix operation must be lower than 1000;
   1.3. order of execution: functions first, then prefix operations, then postfix ones, then infix ones;

2. Create four maps: <String, InfixOperation>, <String, PostfixOperation>, <String, PrefixOperation>, <String, Function> where values are your newly created actions and keys are their string mappings (designations, names):

   2.1. be careful with naming any operation with symbols used to name functions and variables, parser will parse operation designations first;
   2.2. never use digits in operation designations (not to use digits in designations is a good advise);
   2.3. point, comma and parentesis are reserved symbols.

3. Use the maps to initialize ExpressionParser instance, then use its method parse. ExampleExpressionParserFactory (part of test fixture) may be used as a template.