Walter Bright:
1. Go determines the type of (e1 op e2) as the type of the
first operand.
http://golang.org/ref/spec#Arithmetic_operators
I consider this not only surprising (as we expect + to be
commutative) but can lead to unexpected truncation, as in (byte
= byte + int32).
I don't know much about Go, but I have read some Go programs, and
that comment looks suspicious. So I have created a little Go
program:
package main
import ("fmt")
func main() {
var x byte = 10;
var y int = 1000;
z := x + y
fmt.Println(z)
}
If you don't have a Go compiler you can try some code here:
http://play.golang.org/
The result:
http://play.golang.org/p/iP20v0r566
It gives:
prog.go:6: invalid operation: x + y (mismatched types byte and
int)
So despite what the docs say, it seems the two types need to be
the same for the sum to work?
While this program compiles:
package main
import ("fmt")
func main() {
var x byte = 10;
var y int = 1000;
z1 := int(x) + y
fmt.Println(z1)
z2 := x + byte(y)
fmt.Println(z2)
}
And prints:
1010
242
Bye,
bearophile
