# CriticMarkup for Emacs #

`cm-mode` is a minor mode that provides support for [CriticMarkup](http://criticmarkup.com/) in Emacs.

CriticMarkup is a way for authors and editors to track changes to documents in plain text. It defines the following {~~patterns~>tags~~} for marking changes:

- Addition {++ ++}
- Deletion {-- --}
- Substitution {~~ ~> ~~}
- Comment {>> <<}
- Highlight {== ==}{>> <<}

Activating `cm-mode` provides key{--s--} {++bindings ++}to insert these {~~patterns~>markup tags~~} and thus mark one's changes to the text. The provided {==key bindings==}{>>@jk Should I mention that these are nicely mnemonic?<<} are:

- `C-c * a`: add text
- `C-c * d`: delete text
- `C-c * s`: substitute text
- `C-c * c`: insert a comment (possibly with highlight)

The commands to delete or substitute text operate on the region. The command to insert a comment can be used with an active region, in which case the text in the region will be highlighted. It can also be used inside an existing markup to add a comment to it. If it is used anywhere else, it just adds a lone comment. The commands for inserting and substituting text and for inserting a comment {++all ++}put {~~the cursor~>point~~}{>>cursor??!<<} at the correct position, so you can start typing right away.

Note: the [CriticMarkup spec](http://criticmarkup.com/spec.php) says you should avoid putting newlines in CriticMarkup tags and you should always wrap Markdown tags completely. These are wise precautions for `cm-mode` as well.


## Follow changes mode ##

`cm-mode` also provides a simple {~~*follow changes*~>'follow changes'~~} mode. When activated, changes you make to the buffer are automatically marked as insertions or deletions. Substitutions cannot be made automatically (that is, if you mark a word, delete it and then type a replacement, it will still be marked as a sequence of deletion+insertion, not as a substitution), but they can still be made manually with `C-c * s`. You can activate and deactivate follow changes mode with `C-c * F`. When it's active, the modeline indicator for `cm-mode` changes from {--`cm`--}{++`CM`++} to {~~`cm*`~>`CM*`~~}. 


## Keeping track of the author ##

Comments can be used to keep track of who made a particular change. If you want to do this automatically, you can set the variable `cm-author` to an identifier. When this variable is set, its value is automatically added as a comment to every change you make, preceded by `@`. If you explicitly make a comment with `C-c * c`, the value of `cm-author` is inserted at the beginning of the comment.

The variable `cm-author` can be set globally through Customize (or with `setq-default` in your init file). This sets the global value. You can override this global value in a particular buffer by setting a buffer-local value. There are two ways to do this: you can use `C-c * t`, which will only set the value for the current session, or you can use a file-local (or directory-local) variable, which makes sure the value is set every time the file is loaded. (Note: if you use [Pandoc](http://johnmacfarlane.net/pandoc/), you can specify file-local variables with html comments, since Pandoc ignores html comments for all output format.)


## Navigating changes ##

You can jump to the previous/next change with the commands `C-c * b` and `C-c * f`, respectively. If point is inside a change, you can jump out of it with `C-c * *`.


## Accepting or rejecting changes ##

You can interactively accept or reject a change by putting the cursor inside it and hitting `C-c * i`. For additions, deletions and substitutions, you get a choice between `a` to accept the change or `r` to reject it. There are two other choices, `s` to skip this change or `q` to quit. Both leave the change untouched and if you're just dealing with the change at point, they are essentially identical. {>>They have different functions when accepting or rejecting all changes interactively, though.<<}

For comments and highlights, the choices are different: `d` to delete the comment or highlight (whereby the latter of course retains the {~~commented~>highlighted~~} text, but the comment and the markup are removed), or `k` to keep the comment or highlight. Again `q` quits and is essentially identical to `k`. (Note that you can also use `s` instead of `k`, in case you get used to skipping changes that way.)

You can {++interactively ++}{>>@jk<<}accept or reject{-- interactively--}{>>@jk<<} all changes with `C-c * I` (that is a capital `i`). This will go through each change asking you whether you want to accept, reject or skip it, or delete or keep it. Typing `q` quits the accept/reject session.



## Font lock ##

`cm-mode` also adds the markup patterns defined by CriticMarkup to `font-lock-keywords` and provides customisable faces to highlight them. The customisation group is called `criticmarkup`.

You may notice that changes that span multiple lines are not highlighted. The reason for this is that multiline font lock in Emacs is not straightforward. There are ways to deal with this, but since `cm-mode` is a minor mode, it could interfere with the major mode's font locking mechanism if it did that.

To mitigate this problem, you can use soft wrap (with `visual-line-mode`). Since each paragraph is then essentially a single line, font lock works even across multiple (visual) lines.


## Disclaimer ##

`cm-mode` should be considered alpha software, so try at your own risk. If you run into problems, I would very much appreciate it if you open an issue on Github or send me an email.


## TODO ##

- Commands to accept or reject all changes in one go. {>>These won't be bound to keys, though.<<}
- Do not combine two adjacent additions/deletions if the auto-comment is different.
- Mouse support?


## Sceenshot ##

![Emacs CriticMarkup](Emacs_CriticMarkup.png)
