Learn ELVISH with Real Code Examples

count = 0
isDark = $false

fn updateUI {
    echo "Counter: $count"
    if $isDark {
        echo "Theme: Dark"
    } else {
        echo "Theme: Light"
    }
}

fn increment {
    count = (math $count + 1)
    updateUI
}

fn decrement {
    count = (math $count - 1)
    updateUI
}

fn reset {
    count = 0
    updateUI
}

fn toggleTheme {
    isDark = (not $isDark)
    updateUI
}

# Simulate actions
updateUI
increment
increment
toggleTheme
decrement
reset

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

a = 0
b = 1
echo $a
echo $b
for i (1 2 3 4 5 6 7 8) {
    c = (math $a + $b)
    echo $c
    a = $b
    b = $c
}

Generates the first 10 Fibonacci numbers.

fn fact [n]{
    if (math $n == 0) {
        return 1
    } else {
        return (math $n * (fact (math $n - 1)))
    }
}
echo (fact 5)

Calculates factorial of a number recursively.

fn isPrime [n]{
    if (math $n < 2) { return $false }
    for i (2..(math $n - 1)) {
        if (math $n % $i == 0) { return $false }
    }
    return $true
}
echo (if (isPrime 13) {"Prime"} else {"Not Prime"})

Checks if a number is prime.

lst = [1 2 3 4 5]
sum = 0
for x $lst {
    sum = (math $sum + $x)
}
echo $sum

Calculates sum of a list of numbers.

s = "HELLO"
r = (reverse $s)
echo $r

Reverses a string.

n = 5
for i (1..10) {
    echo (str $n " x " $i " = " (math $n * $i))
}

Prints multiplication table of a number.

c = 25
f = (math ($c * 9 / 5) + 32)
echo $f

Converts Celsius to Fahrenheit.

temp = 80
thresh = 75
echo (if ($temp > $thresh) {"Alarm: Temperature Too High!"} else {"Temperature Normal"})

Simulates an alarm if a threshold is exceeded.

steps = 10
pos = 0
for i (1..$steps) {
    if (random 1 < 0.5) {
        pos = (math $pos + 1)
    } else {
        pos = (math $pos - 1)
    }
    echo $pos
}

Simulates a 1D random walk.