Learn REBOL with Real Code Examples

count: 0
isDark: false

updateUI: func [] [
    print join "Counter: " count
    print join "Theme: " (either isDark ["Dark"] ["Light"])
]

increment: func [] [
    count: count + 1
    updateUI
]

decrement: func [] [
    count: count - 1
    updateUI
]

reset: func [] [
    count: 0
    updateUI
]

toggleTheme: func [] [
    isDark: not isDark
    updateUI
]

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

Demonstrates a simple counter with theme toggling using Rebol variables and functions.

a: 0
b: 1
print a
print b
foreach i 1 2 3 4 5 6 7 8 [
    c: a + b
    print c
    a: b
    b: c
]

Generates first 10 Fibonacci numbers.

fact: func [n][
    either n = 0 [1] [n * fact n - 1]
]
print fact 5

Calculates factorial of a number.

is-prime?: func [n][
    if n < 2 [return false]
    foreach i 2 to n - 1 [
        if n // i = 0 [return false]
    ]
    true
]
print either is-prime? 13 ["Prime"] ["Not Prime"]

Checks if a number is prime.

lst: [1 2 3 4 5]
sum: 0
foreach n lst [sum: sum + n]
print sum

Calculates the sum of a block of numbers.

s: "HELLO"
r: reverse s
print r

Reverses a string.

n: 5
foreach i 1 2 3 4 5 6 7 8 9 10 [
    print rejoin [n " x " i " = " n * i]
]

Prints multiplication table of a number.

c: 25
f: (c * 9 / 5) + 32
print f

Converts Celsius to Fahrenheit.

temp: 80
thresh: 75
print either temp > thresh ["Alarm: Temperature Too High!"] ["Temperature Normal"]

Simulates an alarm when temperature exceeds a threshold.

steps: 10
pos: 0
foreach i 1 2 3 4 5 6 7 8 9 10 [
    if random 1 < 0.5 [pos: pos + 1] [pos: pos - 1]
    print pos
]

Simulates a 1D random walk.