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I have to create a function about peano numbers defined as the following datatype:

datatype 'a peano = P of ('a -> 'a) * 'a -> 'a

I have to create a function about peano numbers defined as the following datatype:

datatype 'a peano = P of ('a -> 'a) * 'a -> 'a

val zero = P(fn (f, x) => x)

The function that i have to implement finds the succesive peano number of the peano parameter P(p).

This is what I have written:

fun suc (P(p)) = case P(p) of P(fn(f,x)=>x) => P(fn(f,x)=>f(x));

The problem is that i get these errors:

stdIn:4.33-4.36 Error: syntax error: deleting FN LPAREN

stdIn:4.43 Error: syntax error found at RPAREN

I don't know what Im doing wrong please help!!

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# Standard ML help datatype problem

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