@@ -1,6 +1,15 @@

 from __future__ import print_function

 import sys

 import inspect

+import contextlib

+

+@contextlib.contextmanager

+def redir_stdout(new):

+    old = sys.stdout

+    sys.stdout = new

+    yield

+    sys.stdout = old

+

 SPACE = None

 class _RUN: pass

@@ -139,7 +148,7 @@ class Reader(object):

         c = 80 // (mlen + 2)

         while words:

             head, words = words[:c], words[c:]

-            print(' '.join(x.center(mlen) for x in head))

+            print(' '.join(x.center(mlen) for x in head), file=self.out)

     def forget(self, stack, rstack=None):

         self.program_ctr += 1 # since the program counter doesn't update until after the yield

@@ -179,10 +188,10 @@ class Reader(object):

             self.program_ctr -= 1

         newfun.__name__ = '_forth_%s' % name

     def prog_print(self, stack, rstack=None):

-        print('<%d>' % len(self.program), end=' ')

+        print('<%d>' % len(self.program), end=' ', file=self.out)

         for n in self.program:

-            print(n, end=' ')

-        print()

+            print(n, end=' ', file=self.out)

+        print(file=self.out)

     def set_pctr(self, v):

         self.program_ctr = v

@@ -217,7 +226,7 @@ class Reader(object):

         dst = stack.pop()

         self.set_pctr(dst)

-    def __init__(self):

+    def __init__(self, out=sys.stdout):

         self.sym_words = SymbolDict()

         self.stack = []

         self.rstack = []

@@ -226,6 +235,7 @@ class Reader(object):

         self.pcs = []

         self.mode = 0; # 0 - Normal; 1 - string reading

         self.program_ctr = 0

+        self.out = out

         self.add_symbol('words')(self.words)

         self.add_symbol('.p')(self.prog_print)

         self.add_symbol(':')(self.colon)

@@ -260,13 +270,13 @@ class Reader(object):

     def read(self, inp, silent=False):

         self.inp = [inp]

         delim = SPACE

-        if not silent: print(self.program_ctr, end='? ')

+        if not silent: print(self.program_ctr, end='? ', file=self.out)

         for word in self.read_word():

             #print('<%s>' % word, end=' ')

             if word == _RUN:

                 if not silent:

-                    print(' ok')

-                    print(self.program_ctr, end='? ')

+                    print(' ok', file=self.out)

+                    print(self.program_ctr, end='? ', file=self.out)

                 continue

             elif word == '."':

                 out = []

@@ -274,7 +284,7 @@ class Reader(object):

                 while word != '"':

                     out.append(self.__getword)

                     word = self.__getword()

-                print(' '.join(out))

+                print(' '.join(out), file=self.out)

                 continue

             elif word == '': continue

             self.stack.append(word)

@@ -284,13 +294,15 @@ class Reader(object):

             sym = self.stack.pop()

         result = None

         if sym.lower() in self.symbols:

-            result = self.symbols[sym.lower()](self.stack, self.rstack)

+            with redir_stdout(self.out):

+                result = self.symbols[sym.lower()](self.stack, self.rstack)

         else:

             result = self.numberp(sym)

             if result is None: raise ValueError("Symbol %r not found" % sym)

             else:

                 self.stack.append(result)

         return result

+

     def numberp(self, sym):

         is_valid = -1 # -1 = undecided, 0 = False, 1 = True

         typ = int

@@ -470,8 +482,7 @@ def clear(stack, rstack):

     del stack[:]

     del rstack[:]

-if __name__ == '__main__':

-    import sys

+def init_reader():

     reader = Reader()

     reader.compile(*'0= 0 ='.split(None,1))

     reader.compile(*'0> 0 >'.split(None,1))

@@ -504,6 +515,11 @@ if __name__ == '__main__':

     reader.compile(*'loop r> 1+ r> 2dup >r >r < invert until rdrop rdrop'.split(None, 1))

     reader.compile('begin', 'markr')

     reader.compile('until', 'invert if jmpr else clrjmp then')

+    return reader

+

+if __name__ == '__main__':

+    import sys

+    reader = init_reader()

     import argparse

     parser = argparse.ArgumentParser()