if/else

The if expression evaluates a condition and then chooses to run a block based on the condition.

For example, you can print "yes", based on a true condition:

if true {
  print yes
} else {
  print no
}

Alternately, you can print "no", based on a false condition:

if false {
  print yes
} else {
  print no
}

The else part of if is optional. If not provided, if a condition is false, the if expression returns null.

The code that follows the else is an expression rather than a block, allowing any number of follow-on if expressions as well as other types of expressions. For example, this expression returns 100: if false { 1 } else 100.