function <function_name> with <param1>, <param2>, ...:
    <function_body>
    return <value>

function greet with name:
    set message to f"Hello, {name}!"
    return message

set greeting to call greet with "Alice"
print greeting  # Prints: Hello, Alice!

function <name> with <required_param>, <optional_param> = <default_value>:
    <function_body>

function greet with name, greeting = "Hello":
    return f"{greeting}, {name}!"

print call greet with "Alice"           # Prints: Hello, Alice!
print call greet with "Bob", "Hi"       # Prints: Hi, Bob!

function create_user with username, role = "user", active = true:
    return f"{username} ({role}) - Active: {active}"

print call create_user with "alice"                    # alice (user) - Active: true
print call create_user with "bob", "admin"             # bob (admin) - Active: true
print call create_user with "charlie", "mod", false    # charlie (mod) - Active: false

function <name> with ...<param_name>:
    # param_name is a list of all provided arguments

function sum with ...numbers:
    let total to 0
    for n in numbers:
        let total to total plus n
    return total

print call sum with 1, 2, 3        # Prints: 6
print call sum with 10, 20, 30, 40 # Prints: 100
print call sum                      # Prints: 0 (empty list)

function log_message with level, ...messages:
    for msg in messages:
        print f"[{level}] {msg}"

call log_message with "INFO", "Starting", "Loading", "Ready"
# Prints:
# [INFO] Starting
# [INFO] Loading
# [INFO] Ready

call <function> with <param_name>: <value>, <param_name>: <value>

function create_point with x, y, z:
    return f"Point({x}, {y}, {z})"

# Using named arguments in any order
print call create_point with z: 3, x: 1, y: 2
# Prints: Point(1, 2, 3)

function greet with name, greeting = "Hello", punctuation = "!":
    return f"{greeting}, {name}{punctuation}"

# Positional for first arg, named for specific optional arg
print call greet with "Alice", punctuation: "?"
# Prints: Hello, Alice?

# Skip middle parameter using named argument
print call greet with "Bob", punctuation: "..."
# Prints: Hello, Bob...

function add with a, b:
    return a plus b

set result to call add with 5, 3
print result  # Prints: 8

function divide_with_remainder with a, b:
    let quotient to a divided by b
    let quotient to call floor with quotient
    set remainder to a mod b
    return quotient, remainder

set q, r to call divide_with_remainder with 10, 3
print q  # Prints: 3
print r  # Prints: 1

function get_point:
    return 10, 20

set x, y to call get_point
print x  # Prints: 10
print y  # Prints: 20

let x to 10
let y to 20
let x, y to y, x  # Swap values
print x  # Prints: 20
print y  # Prints: 10

function get_min_max with nums:
    let min_val to nums at 0
    let max_val to nums at 0
    for n in nums:
        if n is less than min_val:
            let min_val to n
        if n is greater than max_val:
            let max_val to n
    return min_val, max_val

set numbers to list 5, 2, 8, 1, 9, 3
set lo, hi to call get_min_max with numbers
print lo  # Prints: 1
print hi  # Prints: 9

set double to function with x: return x times 2
set result to call double with 5
print result  # Prints: 10

set triple to function with x: x times 3
print call triple with 4  # Prints: 12

set calculate to function with a, b:
    set sum to a plus b
    print f"Sum: {sum}"
    return sum

set result to call calculate with 3, 4
print result  # Prints: 7

set add to function with a, b: a plus b
set multiply to function with x, y: x times y

print call add with 2, 3       # Prints: 5
print call multiply with 4, 5  # Prints: 20

# Absolute value function
set abs_value to function with n:
    if n is less than 0:
        return n times -1
    return n

print call abs_value with -5  # Prints: 5
print call abs_value with 5   # Prints: 5

function calculate_total with price, quantity, tax_rate:
    set subtotal to price times quantity
    set tax to subtotal times tax_rate
    return subtotal plus tax

set total to call calculate_total with 10.0, 3, 0.08
print total

set global_var to "global"

function test_scope:
    set local_var to "local"
    print global_var  # Can access global variables
    print local_var   # Can access local variables

call test_scope
print global_var  # OK: global variable
print local_var   # Error: local_var is not defined

function fibonacci with n:
    if n is less than 2:
        return n
    
    set a to 0
    set b to 1
    
    for i in range 2 to n:
        set temp to b
        let b to a plus b
        let a to temp
    
    return b

print call fibonacci with 10  # Prints: 55

function factorial with n:
    if n is less than or equal 1:
        return 1
    
    let result to 1
    for i in range 2 to n:
        let result to result times i
    
    return result

print call factorial with 5  # Prints: 120

function get_grade with score:
    if score is greater than 90:
        return "A"
    else if score is greater than 80:
        return "B"
    else if score is greater than 70:
        return "C"
    else:
        return "F"

print call get_grade with 85  # Prints: B