Loops

Loops in Fuse are really similar to the ones found in the Lua with a little bit syntax sugar inorder to make them more verstile. In this page we are going over different types of loops in the Fuse language.

For Loops

The only form of for loop in Fuse is what you may know as foreach in other languages, It means that even numeric for loops are done with foreach. We can acheive this with the help of ranges, For example this code would print Looping around 10 times.

for i in 1..10 do
  print("Looping around")
end

We can also use the same syntax for looping over any type implementing Iterator or IntoIterator traits.

for item in collection do
  print(item)
end

If we want to loop through items with their indeces we should use their enumerate iterator which will provide the current index as well as the element.

for (index, item) in collection.iter().enumerate() do
  print(index, item)
end

Note Current iteration is stored in an immutable variable so we are not allowed to reassign them. If we want to reassign it we can use mut keyword before binding the identifier.

for (index, mut item) in collection.iter().enumerate() do
  item += 1
  print(index, item)
end

While Loop

While loops can be used to create custom repeating blocks of code, A while loop will check a condition expression and if it is a truthy value it would run the do block of code and get backs to checking condition again.

while i > 0 do
  i -= 1
end

Repeat Loops

There are 2 variants of repeat loop, On it the repeat {body} until {condition} syntax which is similar to a while loop with one difference; It will first run the body and then checks the conditions so it would always run the body at least one time if the condition isn’t satisfied.

repeat
  x += 1
until x < 100

The other variant is a repeat {body} end expression which dosn’t have an exit condition and would run infinitly unless developer explicitly break out of the loop.

repeat
  let dt = delta_time()
  game.update(dt)
end

Break Statement

Break statement is used to terminate execution of a loop. For example given the last repeating loop we can break out of it if update method returns false.

repeat
  let dt = delta_time()
  if not game.update(dt) then
    break
  end
end

Note: A break statement will only break out of the most inner loop.

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