(I suspect this is just another "generics" proposal masquerading as
something else - but I could find a discussion of this using search)
I was wondering about the possibility of passing concrete types to
functions as parameters - the onyl requirement being that the concrete type
satisfies the interface
And to minimize pain I only insist on using new, make, (and any interface
methods)
eg
package main
import (
"fmt"
)
type (
I interface {
ToString() string
}
B byte
F float32
)
func (b B) ToString() string { return fmt.Sprint(b) }
func (f F) ToString() string { return fmt.Sprint(f) }
func makeStringy(x %I) I { //lets use % here to indicate x "is type" not "of
type"
xarr = make([]x, 10) //nonsense example of using make
return x[3]
}
func main() {
var (
b1 B = 1
f1 F = 1.0
)
fmt.Println(b1.ToString(), f1.ToString())
b2 := makeStringy(B)
f2 := makeString(I)
fmt.Println(b2.ToString(), f2.ToString())
}
So my question is not really "is this a good idea" (I think its ok) - but
"how easy would this be to do? (and if implemented would it contain extra
run time overhead compared to that already used when implementing
interfaces ?
The key part of the example is f the function "makeStringy" - all is
required here is that x is a Type that satisifies the interface I
As I understand it data passed as an interface already contains a back
reference to the underlying type (or the other way round) .. so here when I
pass a type to the function (as an interface implementing variable) I need
a back reference to the type .. and the only way I can use the variable is
make and new - so the additional implementation details are minimal.
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