Hi,
this is a free math parser, that I started for some studies. This parser is case sensitive, so a is different from A. Which means, pi is diferent from PI.

All the constants MUST BE in lower case or it'll be a variable or invalid symbol.

The supported operations are:
-> + (Sum)
-> - (Subtraction)
-> * (Multiplication)
-> / (Division)
-> ^ (Potenciation)

Supported functions
-> log(a,b): Return logarithm where 'a' is the exponent and 'b' is the base
-> sin(a), cos(a), tan(a): Return sine, cosine and tangent, respectively, where 'a' is a value in radians
-> abs(a): Returns the absolute value of 'a'
-> max(a,b), min(a,b): Return max and min (respectively) between 'a' and 'b'

Supported constants:
-> pi = 3.141592653589793 (the same value of Math.PI)
-> e  = 2.718281828459045 (the same value of Math.E)

The variables MUST start with a LETTER(A-z) or UNDERLINE(_) and can have numbers from second character.

PUBLIC METHODS:
-> Constructor(exp) = expression that will be evaluated.
-> setVariable(variable, value) = Create (if not exists) or change a variable value.
-> changeExpression(exp) = changes expression that will be evaluated.
-> evaluate() = evaluate the expression with the variables values.

###### CHANGELOG ######
v1.1 
- Added functions support(log, sin, cos, tan, abs, max, min)
- Added constants (pi, e)
- Corrected subtraction bug

v1.2
- Corrected some bugs
- Granulated verifyFunction code