Sunday, July 1, 2007

SEEing LaTeX 3: From PDFView to SubEthaEdit

In my last post, I presented an AppleScript that took us from a LaTeX document in SubEthaEdit to an appropriate portion of the corresponding PDF document in PDFView. This useful action is possible thanks to the magic of pdfsync.

What's more, pdfsync can be used to work both ways. Let's take a look at how to go from a PDF document open in PDFView to the appropriate line in the LaTeX document. In PDFView, you can command-click in the PDF, which invokes a shell command to presumably take you to the right spot in your editor. This works very nicely in TextMate, for example.

PDFView has a "command" text field and an "arguments" text field in its preferences. I don't really see why it's broken into two fields, but that's how it is, so that's what we'll work with. The arguments can include "%file" and "%line" tokens to indicate the file and line number, respectively. PDFView substitutes those tokens appropriately, and runs the script.

SubEthaEdit has the see command line tool that lets us open a file. That will be our starting point. Shockingly, it doesn't have a switch to go to a particular line! We'll work around that with AppleScript. This will be needlessly ugly, I'm afraid.

The see tool opens a file, and makes it the front document. That is the behavior we want for the document, so we'll start there and build a shell script to extend the behavior. We won't try to expose all the options of see in our script, instead just opening a file and going to a given line. We'll call the script seeline, and take its first argument to be the filename.

The next step in the script is to set the selection in the front document to a line number given as the second script argument. This is easy enough with AppleScript, and is a fairly direct transcription of the English-language description. Unfortunately, that turns out not to be enough. The selection is set as desired, but the selection may not be visible! What's worse, there is nothing in SubEthaEdit's AppleScript dictionary that lets us scroll the view as needed.

SubEthaEdit does have a "Jump to Selection" item in its "Find" menu. We could just hit command-J after PDFView transfers us to the LaTeX document in SubEthaEdit, I guess, but it is inelegant, at best. Instead, let's try something else. AppleScript can be used to script the user interface. You may need to first open the AppleScript Utility (why isn't this a preference pane, anyway?) and check the "Enable GUI Scripting" box. We can then use System Events to directly work with the menus of SubEthaEdit, choosing the "Jump to Selection" item.

Taken all together, we get a script:
#!/bin/sh
#
# Brings document to front in SubEthaEdit, opening if necessary, and
# selects given line.
#

#$Id: seeline.sh,v 1.4 2007/07/01 18:28:31 mjb Exp $


/usr/bin/see "$1"
/usr/bin/osascript > /dev/null <<ASCPT

tell application "SubEthaEdit"
    tell front document to set selection to paragraph $2
end tell

tell application "System Events"
    tell process "SubEthaEdit"
        tell menu bar 1
            tell menu bar item "Find"
                tell menu 1
                    click menu item "Jump to Selection"
                end tell
            end tell
        end tell
    end tell
end tell
ASCPT

All the AppleScript is included as a here document, which prevents lots of trouble with how the shell processes quotes and other characters.

I'm not pleased with using UI scripting. It seems fragile and likely to break with updated version of SubEthaEdit. Clearly, this should be an option for the see command line tool, which pretty much means it needs to be handled by the developers.

Whatever my feelings on the aesthetics of UI scripting, the important question is something else: does it work? Yes, it does, and pretty well at that. I have saved the script as ~/Library/bin/seeline, and set the "Command" and "Arguments" in the PDFView preferences to '$HOME/Library/bin/seeline' and '"%file" %line', respectively. Command-clicking in the PDF takes me to the LaTeX file.

Edit: Fixed formatting of included script.

Update: As of version 3.0 of SubEthaEdit, the see command line tool has an option to go to a desired line.

3 comments:

dom said...

Hi!
Thank you for using SubEthaEdit so nicely ;) I see that the xhtml export uses a two line feed in your case. I think this might be a bug in the xhtml export. If you have a consistent way to reproduce it, I would be happy to fix it!
best,
dom

Michael said...

@dom

Thanks for making such a pleasant editor to use!

Your aggressive bug-handling is great to see, and I can consistently reproduce the behavior, but I'm not so sure it is a bug. If I Copy as XHTML and paste into, say, a RapidWeaver HTML page, the formatting is correct. I suspect that the problem comes from inserting the XHTML from SubEthaEdit directly into Blogger's "New Post" text form. There are thus two attempts at formatting the text nicely into paragraphs, which messes things up a bit. I was, I must admit, too lazy to be bothered about it while getting the posts ready.

I'll experiment a bit with trimming the newlines or the break tags from the XHTML and see what happens.

dom said...

ah great to hear that it doesn't seem to be a bug at our end. I recently hat a similar issue that I sadly can't reproduce while blogging via MarsEdit so I thought it may have been on our side. However, if SubEthaEdit ever adds two brs instead of one, please file a bug at https://www.codingmonkeys.de/bugs

Thanks for your support,
dom