> The fact that git works on lines of text [...] we could be looking at the alterations to the abstract syntax tree. Fundamentally git does not operate on text

> The fact that git works on lines of text [...] we could be looking at the alterations to the abstract syntax tree. Fundamentally git does not operate on text, it operates on files (content addressed SCM not a ledger of text diffs); diffs are generated upon request between arbitrary merkel trees. So there is no need to implicate git in such a tool, it can be independent: GIT_EXTERNAL_DIFF When the environment variable GIT_EXTERNAL_DIFF is set, the program named by it is called to generate diffs, and Git does not use its builtin diff machinery. For a path that is added, removed, or modified, GIT_EXTERNAL_DIFF is called with 7 parameters: path old-file old-hex old-mode new-file new-hex new-mode