Python difflibparser

difflibparser is a simple module that parses the output of difflib.ndiff. It takes two strings and exposes a getNextLine() method that returns a dictionary that represents the next line in the diff. The return type always has a 'code' key that contains one of the following values:

class DiffCode:
    SIMILAR = 0         # line hasn't changed between the files, its diff starts with '  '
    RIGHTONLY = 1       # line exists in the right file only, its diff starts with '+ '
    LEFTONLY = 2        # line exists in the left file only, its diff starts with '- '
    CHANGED = 3         # line has incremental changes on the left file, the diff is represented
                            as three of four lines in the order ('-', '+', '?'), ('-', '?', '+')
                            or ('-', '?', '+', '?')

If the returned code is DiffCode.CHANGED, the result will also contain 'rightchanges' and 'rightchanges' keys, each is a list of indices that have changed on the left and right side respectively. One of these two can be empty but not both.

Usage

diff = DifflibParser(leftText.splitlines(), rightText.splitlines())
for d in diff:
    print(d)

left file:

line1
lineTwo
lineThrees
line4
line6

right file:

line1
xlineTw0
lineThree
line4
line66

For the two files above, these are the returned results:

{'code': 0, 'line': 'line1'}
{'code': 3, 'line': 'lineTwo', 'newline': 'xlineTw0', 'rightchanges': [0, 7], 'leftchanges': [6]}
{'code': 3, 'line': 'lineThrees', 'newline': 'lineThree', 'rightchanges': [], 'leftchanges': [9]}
{'code': 0, 'line': 'line4'}
{'code': 3, 'line': 'line6', 'newline': 'line66', 'rightchanges': [5], 'leftchanges': []}

Which matches the output of difflib.ndiff:

line1
- lineTwo
?       ^
+ xlineTw0
? +      ^
- lineThrees
?          -
+ lineThree
  line4
- line6
+ line66
?      +