String Differencing
From WinMerge Development Wiki
String Differencing is not a compare engine as is. It is more like a tool we use for getting differences inside two lines for editor. So editor can highlight these changes.
Contents |
[edit] Differences
String differencing understands the same compare options than other compare engines. It actually should match those engines as much as possible. Though it must do more job since other two engines only see there is some difference. But String difference must detect what the actual difference is.
[edit] Words and Characters
Most interesting changes happens in words and characters (visible changes). Whole word or just some characters in word change.
For example, if we have lines:
This is one example string.
and
This is second example string.
Differencing naturally highlights word one from first string and second from second string.
And in another example:
void funcFirstTest();
and
void funcSecondTest();
Differencing highlights First part from first word and Second part in second word. But it even works like this:
void firstTest();
and
void f1rstTest();
where i is changed to 1.
[edit] Whitespaces
Whitespaces are trickier. Remembering WinMerge allows to ignore whitespace differences.
Simplest example is adding a new word to line:
This is example string.
and
This is another example string.
As is easy to see, adding new word added new whitespace character, which must be highlighted.
[edit] Status
Currently it works pretty good in simple cases. But there are lots of problems with non-trivial cases. InLineDifferencingThoughts has some ideas for improving the feature.
[edit] Unit Tests
There are initial CppUnit unit-tests in source repository in Testing/CppUnit/StringDifferencing folder. Unit tests were recently extented and now they already have fine coverage. But of course there can be always more, as this is tricky area...
[edit] Future developments
- Should string differencing handle also regular expressions?
- Toolify - make it easily accessible from other code (whenever other code needs string differencing)
