boo 0.8.2

Version of implementation Boo of programming language Boo

A version of Boo language, released on May 19, 2008.

Examples:

Hello, World! - Boo (246):

print("Hello, World!")

Factorial - Boo (247):

This example uses recursive factorial definition. The function factorial is called recursively, so it needs an explicit declaration of its return type.

def factorial(n as long) as long:
    if n == 0:
        return 1
    else:    
        return n * factorial(n - 1)

for n in range(0, 17):
	print("${n}! = ${factorial(n)}")

This example uses iterative factorial definition. Variable fact needs an explicit type declaration, since otherwise it will be typed as int, and trying to calculate 13! will cause an overflow error.

fact as long = 1
for i in range(17):
    print("${i}! = ${fact}")
    fact = fact * (i+1)

Fibonacci numbers - Boo (249):

This example uses iterative definition of Fibonacci numbers. The array a is declared to have 16 elements right away, and the elements are calculated later.

a = array(int, 16)
a[0] = a[1] = 1
for i in range(2,16):
    a[i] = a[i-1] + a[i-2]
s=""
for i in range(16):
    s = s + a[i] + ", "
print(s + "...")

Fibonacci numbers - Boo (250):

This example shows the usage of generator fib: it initializes inner variables a and b, and after each call to generator it updates the variables and returns one of them. Function zip is a built-in which returns an IEnumerable that is a “mesh” of two IEnumerables — range and fib.

def fib():
    a, b = 0, 1
    while true:
        yield b
        a, b = b, a + b
 
s=""
for i, n in zip(range(16), fib()):
    s = s+n+", "
print(s+"...")

Quadratic equation - Boo (276):

A = int.Parse(prompt("A = "))
if A==0 :
    print "Not a quadratic equation."
    return
B = int.Parse(prompt("B = "))
C = int.Parse(prompt("C = "))
D = B*B-4*A*C
if D==0 :
    x = -0.5*B/A
    print "x = ${x}"
    return
if D>0 :
    x1 = 0.5*(-B-System.Math.Sqrt(D))/A
    x2 = 0.5*(-B+System.Math.Sqrt(D))/A
    print "x1 = ${x1}"
    print "x2 = ${x2}"
else :
    r = -0.5*B/A
    i = 0.5*System.Math.Sqrt(-D)/System.Math.Abs(A)
    print "x1 = (${r},${i})"
    print "x2 = (${r},-${i})"