Control Flow in Golo

Getting Started with Golo
🚧 This is a work in progess

Golo provides familiar control flow constructs: if/else for conditionals, C-style for loops, foreach for iterating over collections, while loops, and match expressions for pattern-based branching (similar to switch but with condition guards via when/then).

control-flow.golo:

module getting.started.ControlFlow

function main = |args| {

  # If-else
  let x = 8
  if x > 10 {
    println("big")
  } else if x > 5 {
    println("medium")
  } else {
    println("small")
  }

  let age = 20
  if age >= 18 {
    println("You are an adult")
  } else {
    println("You are a minor")
  }

  # For loop
  for (var i = 1, i <= 5, i = i + 1) {
    println("i =", i)
  }

  # Foreach
  foreach item in list["one", "two", "three"] {
    println(item)
  }

  # While
  var counter = 0
  while counter < 5 {
    println(counter)
    counter = counter + 1
  }

  # Match
  let classify = |n| {
    return match {
      when n < 0 then "negative"
      when n == 0 then "zero"
      when n > 0 then "positive"
      otherwise "unknown"
    }
  }
  println("Classify -5:", classify(-5))
  println("Classify 0:", classify(0))
  println("Classify 10:", classify(10))
}

run golo control-flow.golo

Output:

medium
You are an adult
i = 1
i = 2
i = 3
i = 4
i = 5
one
two
three
0
1
2
3
4
Classify -5: negative
Classify 0: zero
Classify 10: positive