Add untokenize() function to allow full round-trip tokenization.
Should significantly enhance the utility of the module by supporting
the creation of tools that modify the token stream and writeback the
modified result.
diff --git a/Lib/test/regrtest.py b/Lib/test/regrtest.py
index 6160b3d..85e784b 100755
--- a/Lib/test/regrtest.py
+++ b/Lib/test/regrtest.py
@@ -91,7 +91,9 @@
compiler - Test the compiler package by compiling all the source
in the standard library and test suite. This takes
- a long time.
+ a long time. Enabling this resource also allows
+ test_tokenize to verify round-trip lexing on every
+ file in the test library.
subprocess Run all tests for the subprocess module.
diff --git a/Lib/test/test_tokenize.py b/Lib/test/test_tokenize.py
index d217404..2ce435f 100644
--- a/Lib/test/test_tokenize.py
+++ b/Lib/test/test_tokenize.py
@@ -1,12 +1,82 @@
-from test.test_support import verbose, findfile
-import tokenize, os, sys
+from test.test_support import verbose, findfile, is_resource_enabled
+import os, glob, random
+from tokenize import (tokenize, generate_tokens, untokenize,
+ NUMBER, NAME, OP, STRING)
if verbose:
print 'starting...'
f = file(findfile('tokenize_tests' + os.extsep + 'txt'))
-tokenize.tokenize(f.readline)
+tokenize(f.readline)
f.close()
+
+
+###### Test roundtrip for untokenize ##########################
+
+def test_roundtrip(f):
+ ## print 'Testing:', f
+ f = file(f)
+ try:
+ fulltok = list(generate_tokens(f.readline))
+ finally:
+ f.close()
+
+ t1 = [tok[:2] for tok in fulltok]
+ newtext = untokenize(t1)
+ readline = iter(newtext.splitlines(1)).next
+ t2 = [tok[:2] for tok in generate_tokens(readline)]
+ assert t1 == t2
+
+
+f = findfile('tokenize_tests' + os.extsep + 'txt')
+test_roundtrip(f)
+
+testdir = os.path.dirname(f) or os.curdir
+testfiles = glob.glob(testdir + os.sep + 'test*.py')
+if not is_resource_enabled('compiler'):
+ testfiles = random.sample(testfiles, 10)
+
+for f in testfiles:
+ test_roundtrip(f)
+
+
+
+###### Test example in the docs ###############################
+
+from decimal import Decimal
+from cStringIO import StringIO
+
+def decistmt(s):
+ """Substitute Decimals for floats in a string of statements.
+
+ >>> from decimal import Decimal
+ >>> s = 'print +21.3e-5*-.1234/81.7'
+ >>> decistmt(s)
+ "print +Decimal ('21.3e-5')*-Decimal ('.1234')/Decimal ('81.7')"
+
+ >>> exec(s)
+ -3.21716034272e-007
+ >>> exec(decistmt(s))
+ -3.217160342717258261933904529E-7
+
+ """
+ result = []
+ g = generate_tokens(StringIO(s).readline) # tokenize the string
+ for toknum, tokval, _, _, _ in g:
+ if toknum == NUMBER and '.' in tokval: # replace NUMBER tokens
+ result.extend([
+ (NAME, 'Decimal'),
+ (OP, '('),
+ (STRING, repr(tokval)),
+ (OP, ')')
+ ])
+ else:
+ result.append((toknum, tokval))
+ return untokenize(result)
+
+import doctest
+doctest.testmod()
+
if verbose:
print 'finished'