(self, env, actual_params)
return SubsClass(env).substitute(self.function_body, subs)
Given a set of actual parameter, returns the 'value' of the
        function by substitutiong formal parameters with their actual
        values.
Given a set of actual parameter, returns the 'value' of the
        function by substitutiong formal parameters with their actual
        values.
Given a set of actual parameter returns the value of the function by substitutiong formal parameters with their actual values .
def interpret(self, env, actual_params):
        """Given a set of actual parameter, returns the 'value' of the
        function by substitutiong formal parameters with their actual
        values.
        """
        if len(actual_params) !=  len(self.formal_params):
            raise ValueError('The numbe of actual parameters does not match '
                             'with the number of formal parameters')
        subs = dict(zip(self.formal_params, actual_params))
        SubsClass = type(env.substituter)
        return SubsClass(env).substitute(self.function_body, subs)
def interpret ( self , env , actual_params ) : if len ( actual_params ) != len ( self . formal_params ) : raise ValueError ( 'The numbe of actual parameters does not match ' 'with the number of formal parameters' ) subs = dict ( zip ( self . formal_params , actual_params ) ) SubsClass = type ( env . substituter ) return SubsClass ( env ) . substitute ( self . function_body , subs )