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Comment by nailer | Hacker News Reader

This is awesome, but one request: can you please extend it into a real (ie, AST based) diffing tool? Current diffing tools all compare the text (which is basically an input format) rather than the AST, and hence end up focusing on formatting rather than actual changes.

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You could hack a diffing tool that reformats both the before and after and shows the diff of the generated text.

This would not catch changes like

    --val  x =  [1]
    ++var x = [
    ++  1,
    ++];

as expected, while it would give you a slightly more verbose diff if the change was

    --val x = [short(), short()];
    ++val x = [
    ++  a_really_long_name_that_pushes_the_line_length(),
    ++  a_really_long_name_that_pushes_the_line_length(),
    ++];

If you auto-format as a commit hook then all of the changes you see will be AST-based, and you can ignore the style.

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