def getFuncExpr(exprTok, eqnVars, graphVars):
    """Allocates variables in equation to graph variables to give final function compatible for plotting

    Arguments:
        exprTok {list} -- expression tokens
        eqnVars {list} -- variables in equation
        graphVars {list} -- variables for plotting

    Returns:
        expr {numpy.array(2D)/function(3D)} -- expression converted to compatible data type for plotting
    """
    expr = 0
    coeff = 1
    for token in exprTok:
        if isinstance(token, Variable):
            varProduct = 1
            for value, power in zip(token.value, token.power):
                varProduct *= graphVars[eqnVars.index(value)]**power
            expr += coeff * token.coefficient * varProduct
        elif isinstance(token, Constant):
            expr += coeff * token.value
        elif isinstance(token, FuncOp):
            pass
        elif isinstance(token, Binary) and token.value == '-':
            coeff = -1
        elif isinstance(token, Binary) and token.value == '+':
            coeff = 1
    return expr


#######
# GUI #
#######