Print a result or stop the program
Silex provides three direct effects for observing or stopping a program:
print, assert, and panic.
Print values
func main() {
let x = 10
let y = 5
print("x=", x, ", y=", y)
}
print evaluates its arguments from left to right, inserts no separator, and
adds one final line break. It accepts strings, numbers, and booleans. The
program above prints:
x=10, y=5
String interpolation can prepare the same text before the call when the result must be reused.
Check a condition
assert(count > 0, "count must be positive")
If the condition is false, assert writes a source-located diagnostic to
standard error, then exits the program with status 1. A true condition
produces nothing and lets execution continue.
Stop with a message
panic("impossible state")
panic always writes a source-located diagnostic to standard error and exits
with status 1. Prefer a Result when the caller must
be able to recover from the failure.