[clean-list] (no subject)

[Jigang Sun]

On page 16 of the book Functional programming in Clean at http://www.st.cs.ru.nl/papers/cleanbook/CleanBookI.pdf, operator + is defined as an overloaded function(class) on different type such as Int, Real etc, so each instance of the class is a different function. While an example of polymorphism using this operator was given 

double :: a -> a | + a  //defined on Int, Real etc
double n = n + n

the function double is defined  in terms of overloaded function.

my question is now that each operation + carries on a different type is a different function, so each operation the function double do on a separate type should be semantically different. Could anyone advice me the boundary between the two concepts polymorphism and overloading. From the example on the book and the Clean's permission to define a function in terms of overloaded function, the two concepts are mixing together. 

Thanks. 
Jigang








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