1.gop

import (
  "strconv"
)

func add(x, y string) (int, error) {
  return strconv.atoi(x)? + strconv.atoi(y)?, nil
}

func addSafe(x, y string) int {
  return strconv.atoi(x)?:0 + strconv.atoi(y)?:0
}

// Error handling
// We reinvent the error handling specification in Go+. We call them ErrWrap expressions:

// expr! // panic if err
// expr? // return if err
// expr?:defval // use defval if err

println `add("100", "23"):`, add("100", "23")!

sum, err := add("10", "abc")
println `add("10", "abc"):`, sum, err

println `addSafe("10", "abc"):`, addSafe("10", "abc")


a := [x*x for x <- [1, 3, 5, 7, 11]]
println a
b := [x*x for x <- [1, 3, 5, 7, 11], x > 3]
println b
c := [i+v for i, v <- [1, 3, 5, 7, 11], i%2 == 1]
println c
d := [k+","+s for k, s <- {"Hello": "xsw", "Hi": "Go+"}]
println d

arr := [1, 2, 3, 4, 5, 6]
e := [[a, b] for a <- arr, a < b for b <- arr, b > 2]
println e

x := {x: i for i, x <- [1, 3, 5, 7, 11]}
println x
y := {x: i for i, x <- [1, 3, 5, 7, 11], i%2 == 1}
println y
z := {v: k for k, v <- {1: "Hello", 3: "Hi", 5: "xsw", 7: "Go+"}, k > 3}
println z