# amachine.py
# a tiny stack machine for our new language A, nothing special.
import math, os, re, operator, sys
end=[]
def run(l):
stack=[[]]
for i in l:
if i is end:
f=stack.pop()
i=f[0](*f[1:])
if callable(i):
stack.append([i])
else:
stack[-1].append(i)
# end of amachine.py
# atest.py (written in our new language A)
# encoding: acodec
sys.stdout.write "Hello!\n";
sys.stdout.write "4 * sin(pi/4) + 3 = ";
sys.stdout.write str
operator.add operator.mul 4 math.sin math.pi/4;; 3;;;
sys.stdout.write "\n";
# End of atest.py
# Looks like atest.py can be executed by our tiny stack machine.
# After all, it is written in Language A.
# But certainly it can not be executed by the python interpreter directly.
# Obviously, atest.py is not written in Python.
# Or is it?
# After load the following module, it is Python enough for the python interpreter.
# acodec.py
import encodings, codecs, re, sys
# a mini tokenizer
_qs=r"'(?:[^'\\\n]|\\.|\\\n)*?'(?!')|'''(?:[^\\]|\\.)*?'''"
String = r"[uU]?[rR]?(?:%s|%s)"%(_qs, _qs.replace("'",'"'))
Comment=r'\#.*'
Name= r"[^#\"'\s\n;]+"
tok_re=re.compile(r"%s|%s|%s|(?P<e>[;\.])"%(Name, String , Comment))
# Our StreamReader
class aStreamReader(codecs.StreamReader):
def readline(self, size=None, keepends=True):
def repl(m):
r=m.group()
return "end," if m.group("e") else r+","
if getattr(self, "pysrc", None)==None:
r=self.stream.read().decode("utf8")
r="from amachine import *;run([%s])" % tok_re.sub(repl,r)
self.pysrc=r.splitlines()
return u'%s\n'%self.pysrc.pop(0) if self.pysrc else u''
def search_function(s):
if s!="acodec":
return None
u8=encodings.search_function("utf8")
return codecs.CodecInfo( name='acodec',
encode=u8.encode, decode=u8.decode,
incrementalencoder=u8.incrementalencoder,
incrementaldecoder=u8.incrementaldecoder,
streamreader=aStreamReader, # acodec StreamReader
streamwriter=u8.streamwriter)
codecs.register(search_function) # register our new codec search function
# End of acodec.py
# to test
# import acodec
# execfile("atest.py") # Executed like python
# import atest.py # Imported like python
# You can also use site.py or .pth file to load acodec.py automaticly.
# then you can simply:
# python atest.py
