Control Flow

Conditional branching statements.

let age = 18

# Simple if
if (age >= 18)
    print("Adult")
end

# If-else
let score = 75
if (score >= 60)
    print("Pass")
else
    print("Fail")
end

# Else-if chain
let grade = 85
let letter
if (grade >= 90)
    letter = "A"
elsif (grade >= 80)
    letter = "B"
elsif (grade >= 70)
    letter = "C"
elsif (grade >= 60)
    letter = "D"
else
    letter = "F"
end
print(letter);  # "B"

The then keyword is an optional separator between the condition and the body of an if or elsif statement. It improves readability, especially for single-line conditionals.

# Multi-line with then
if age >= 18 then
    print("Adult")
end

# Single-line with then
if user != null then print("Welcome, " + user.name) end

# Works with elsif too
let x = 42
if x > 100 then
    print("big")
elsif x > 10 then
    print("medium")
else
    print("small")
end

# Parentheses and then can be combined
if (score >= 90) then
    grade = "A"
end

# Without then (also valid)
if age >= 18
    print("Adult")
end

Note: then is purely syntactic sugar. Both if condition then ... end and if condition ... end are equivalent. Parentheses around the condition are also optional.

Repeats while a condition is true.

let i = 0
while (i < 5)
    print("Count: " + str(i))
    i = i + 1
end
# Output: Count: 0, 1, 2, 3, 4

Iterates over collections or ranges.

# Iterate over array
let fruits = ["apple", "banana", "cherry"]
for (fruit in fruits)
    print(fruit)
end

# Iterate with range
for (i in range(0, 5))
    print(i);  # 0, 1, 2, 3, 4
end

# Range with step
for (i in range(0, 10, 2))
    print(i);  # 0, 2, 4, 6, 8
end

# Nested loops
for (i in range(1, 4))
    for (j in range(1, 4))
        print(str(i) + " x " + str(j) + " = " + str(i * j))
end
end

Ruby-style postfix conditionals for concise one-liners.

let x = 10
print("big") if (x > 5)

let y = 3
print("small") unless (y > 5)

let status = "active"
print("Welcome!") if (status == "active")
print("Account locked") unless (status != "banned")

Inline conditional expression.

let x = 10
let size = x > 5 ? "large" : "small"
print(size);  # "large"

# Nested ternary
let grade = 85
let letter = grade >= 90 ? "A"
             : grade >= 80 ? "B"
             : grade >= 70 ? "C"
             : grade >= 60 ? "D"
             : "F"
print(letter);  # "B"

Exits the current loop immediately.

Skips to the next iteration of the loop.