"""
Really simple Poly (polynomial class)

Example usage:
>>> from simppoly import Poly
>>> p = Poly([1,2,0,0,3,-4])
>>> p
(1 * (x**0))+(2 * (x**1))+(3 * (x**4))+(-4 * (x**5))
>>> p(10)
-369979
"""

class Poly(object):
    
    def __init__(self, coeffs):
        """
        Coefficients in order of increasing degree, 0 where necessary
        """
        self.coeffs = coeffs
		
    def __call__(self, x):
        """
        Triggers evaluation of string representation for 'x' = x
        """
        return eval(repr(self), {'x':x})
	    
    def __repr__(self):
        """
        Build a string representation, low to high degree, skipping 0 coefficients
        """
        monomials = [ '(%s * (x**%s))' % (c,e)
		for c,e in zip(self.coeffs, range(len(self.coeffs))) if c<>0]
        return ' + '.join(monomials)