Frederic Rentsch wrote:
> Following a call to dedent () it shouldn't be hard to translate leading
> groups of so many spaces back to tabs.
Sure, but the point is more that I don't think it's valid to change to
tabs in the first place.
E.g.:
input = ' ' + '\t' + 'hello\n' +
'\t' + 'world'
output = textwrap.dedent(input)
will yield all of the leading whitespace stripped, which IMHO is a
violation of its stated function. In this case, nothing should be
stripped, because the leading whitespace in these two lines does not
/actually/ match. Sure, it visually matches, but that's not the point
(although I can understand that that's a point of contention in the
interpreter anyway, I would have no problem with it not accepting "1 tab
= 8 spaces" for indentation... But that's another holy war.
> If I understand your problem, you want to restore the dedented line to
> its original composition if spaces and tabs are mixed and this doesn't
> work because the information doesn't survive dedent ().
Sure, although would there be a case to be made to simply not strip the
tabs in the first place?
Like this, keeping current functionality and everything... (although I
would think if someone wanted tabs expanded, they'd call expandtabs on
the input before calling the function!):
def dedent(text, expand_tabs=True):
"""dedent(text : string, expand_tabs : bool) -> string
Remove any whitespace than can be uniformly removed from the left
of every line in `text`, optionally expanding tabs before altering
the text.
This can be used e.g. to make triple-quoted strings line up with
the left edge of screen/whatever, while still presenting it in the
source code in indented form.
For example:
def test():
# end first line with \ to avoid the empty line!
s = '''\
hello
\t world
'''
print repr(s) # prints ' hello\n \t world\n '
print repr(dedent(s)) # prints ' hello\n\t world\n'
"""
if expand_tabs:
text = text.expandtabs()
lines = text.split('\n')
margin = None
for line in lines:
if margin is None:
content = line.lstrip()
if not content:
continue
indent = len(line) - len(content)
margin = line[:indent]
elif not line.startswith(margin):
if len(line) < len(margin):
content = line.lstrip()
if not content:
continue
while not line.startswith(margin):
margin = margin[:-1]
if margin is not None and len(margin) > 0:
margin = len(margin)
for i in range(len(lines)):
lines[i] = lines[i][margin:]
return '\n'.join(lines)
import unittest
class DedentTest(unittest.TestCase):
def testBasicWithSpaces(self):
input = "\n Hello\n World"
expected = "\nHello\n World"
self.failUnlessEqual(expected, dedent(input))
def testBasicWithTabLeadersSpacesInside(self):
input = "\n\tHello\n\t World"
expected = "\nHello\n World"
self.failUnlessEqual(expected, dedent(input, False))
def testAllTabs(self):
input = "\t\tHello\n\tWorld"
expected = "\tHello\nWorld"
self.failUnlessEqual(expected, dedent(input, False))
def testFirstLineNotIndented(self):
input = "Hello\n\tWorld"
expected = input
self.failUnlessEqual(expected, dedent(input, False))
def testMixedTabsAndSpaces(self):
input = " \t Hello\n \tWorld"
expected = "\t Hello\n \tWorld"
self.failUnlessEqual(expected, dedent(input, False))
if __name__ == '__main__':
unittest.main()
-tom!
--
--
http://mail.python.org/mailman/listinfo/python-list
