## Tuesday, January 29, 2008

### Stackless RPython - Recursive

Got input from pypy/rpython developers, and in order to get stackless rpython it was just to add parameter stackless=True and replace parameter gc='ref' with gc='generation' to Translation() method.
# The Computer Language Shootout
# http://shootout.alioth.debian.org/
# based on bearophile's psyco program
# slightly modified by Isaac Gouy
# And adapted to RPython by Amund

def Ack(x, y):
if x == 0: return y+1
if y == 0: return Ack(x-1, 1)
return Ack(x-1, Ack(x, y-1))

def Fib(n):
if n < 2: return 1
return Fib(n-2) + Fib(n-1)

def FibFP(n):
if n < 2.0: return 1.0
return FibFP(n-2.0) + FibFP(n-1.0)

def Tak(x, y, z):
if y < x:
return Tak(
Tak(x-1,y,z),
Tak(y-1,z,x),
Tak(z-1,x,y) )
return z

def TakFP(x, y, z):
if y < x:
return TakFP(
TakFP(x-1.0,y,z),
TakFP(y-1.0,z,x),
TakFP(z-1.0,x,y) )
return z

# RPython stuff starts here

from sys import argv #, setrecursionlimit
#setrecursionlimit(12345678901)

def main(argv):
n = int(argv[1]) - 1
print "Ack(3,%d):" % (n+1), Ack(3, n+1)
print "Fib(" + str(28.0+n) + "," + str(FibFP(28.0+n))
print "Tak(%d,%d,%d): %d" % (3*n, 2*n, n, Tak(3*n, 2*n, n))
print "Fib(3):", Fib(3)
print "Tak(3.0,2.0,1.0):", TakFP(3.0, 2.0, 1.0)
return 0

from pypy.translator.interactive import Translation
#t = Translation(main, standalone=True, gc='ref')
t = Translation(main, standalone=True,
stackless=True, gc='generation')
t.source(backend='c')
path = t.compile()
print path