Go: A question about "methods on types"

[atul khot]

Dear Mark,

Here goes ;-) a code snippet from gotour,

package main

import (
	"fmt"
	"math"
)

type MyFloat float64

func (f MyFloat) Abs() float64 {
	if f < 0 {
		return float64(-f)
	}
	return float64(f)
}

func main() {
	f := MyFloat(-math.Sqrt2)
	fmt.Println(f.Abs())
}

What is happening on line 18?

The syntax
-math.Sqrt2
is this the same as
-math.Sqrt(2)

The lack of parenthesis stumped me...
I understand the rest...

--- thanks atul

[atul khot]

I guess math.Sqrt2 is some constant in the math package...

--- cheerio atul

[Mark Summerfield]

Hi Atul,

Yes you're right math.Sqrt2 is a predefined constant.