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
= lines[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!
