Execute HQ9+/Python

From Rosetta Code
Revision as of 13:19, 2 August 2009 by rosettacode>JimD (Replace if ... elif ... elif ... with dispatch table.)
Execute HQ9+/Python is part of RCHQ9+. You may find other members of RCHQ9+ at Category:RCHQ9+.
Execute HQ9+/Python is an implementation of HQ9+. Other implementations of HQ9+.

This example implements 'H', 'Q', '9' and '+'.

<lang python>import sys

def hello():

   print "Hello, world!"

def quine():

   print src

def bottles():

   for i in range(99,2,-1):       
       print "%d bottles of beer on the wall" % i
       print "%d bottles of beer" % i
       print "Take one down, pass it around"
       print "%d bottles of beer on the wall" % (i-1)
       print
   print "2 bottles of beer on the wall"
   print "2 bottles of beer"
   print "Take one down, pass it around"
   print "1 bottle of beer on the wall"
   print
   print "1 bottle of beer on the wall"
   print "1 bottle of beer"
   print "Take one down, pass it around"
   print "No more bottles of beer on the wall"
   print
   print "No more bottles of beer on the wall"
   print "No more bottles of beer on the wall"
   print "Go to the store and buy some more"
   print "99 bottles of beer on the wall."
   print 

def incr():

   acc +=1

if len(sys.argv) != 2:

   print "Usage: ./hq9p.py script.hq9"
   sys.exit(1)

else:

   f = sys.argv[1]

try:

   s = open(f,"r")

except IOError, e:

   print "Can't open file: " + str(e.args[1])
   sys.exit(1)

acc = 0 src = s.read()

  1. Implement interpreter using a dispatch table

dispatch = {

    'h': hello,
    'q': quine,
    '9': bottles,
    '+': incr
    }

for i in src.lower():

   if i in dispatch:
       dispatch[i]()