Learn IO with Real Code Examples

count := 0
isDark := false

updateUI := method(
    write("Counter: " .. count .. "\n")
    write("Theme: " .. (if(isDark, "Dark", "Light")) .. "\n")
)

increment := method(
    count = count + 1
    updateUI()
)

decrement := method(
    count = count - 1
    updateUI()
)

reset := method(
    count = 0
    updateUI()
)

toggleTheme := method(
    isDark = !isDark
    updateUI()
)

# Simulate actions
updateUI()
increment()
increment()
toggleTheme()
decrement()
reset()

Demonstrates a simple counter with theme toggling using Io objects and message passing.

a := 0
b := 1
write(a .. "\n")
write(b .. "\n")
for(i, 1, 8, do(
    c := a + b
    write(c .. "\n")
    a := b
    b := c
))

Generates the first 10 Fibonacci numbers.

fact := method(n, if(n <= 0, 1, n * fact(n-1)))
write(fact(5) .. "\n")

Calculates factorial of a number recursively.

isPrime := method(n, do(
    if(n <= 1, return(false))
    for(i, 2, n-1, if(n % i == 0, return(false)))
    return(true)
))
write(if(isPrime(13), "Prime\n", "Not Prime\n"))

Checks if a number is prime.

lst := list(1,2,3,4,5)
sum := 0
foreach(x, lst, sum = sum + x)
write(sum .. "\n")

Calculates sum of a list of numbers.

s := "HELLO"
r := s reverse
write(r .. "\n")

Reverses a string.

n := 5
for(i, 1, 10, write(n .. " x " .. i .. " = " .. (n*i) .. "\n"))

Prints multiplication table of a number.

c := 25
f := (c * 9 / 5) + 32
write(f .. "\n")

Converts Celsius to Fahrenheit.

temp := 80
thresh := 75
write(if(temp > thresh, "Alarm: Temperature Too High!", "Temperature Normal") .. "\n")

Simulates an alarm if a threshold is exceeded.

steps := 10
pos := 0
for(i,1,steps, do(
    if(rand() < 0.5, pos = pos + 1, pos = pos - 1)
    write(pos .. "\n")
))

Simulates a 1D random walk.