parse .mxl file with Clojure

Question

I would like to parse an .mxl file (MusicXML) with clojure

So far i've seen a lot of tools to work with .xml files but I can't find a way to work with .mxl, maybe i should convert mxl to xml first but i don't know how to do that neither.

Answer 1

From the Wikipedia page on MusicXML:

The textual representation listed above is verbose; MusicXML v2.0 addresses this by adding a compressed zip format with a .mxl suffix that can make files roughly one-twentieth the size of the uncompressed version.[16]

I'm guessing that your .mxl file is an XML file which has been compressed, and this is why you're getting parse errors. As far I can gather, the compression algorithm is a zip algorithm, so you should be able to use java's zip functionality to get at it.

EDIT

I just had a go at this with a sample .mxl file I found online. The .mxl file, once unzipped contained the xml file within it. I was then able to use following (inspired by this answer) to get the raw XML...

 (defn extract-mxl [path]
   (let [[_ filename] (re-matches #"(.*)\.mxl$" (.getName (java.io.File. path)))
         zipfile (java.util.zip.ZipFile. path)
         zipentry (.getEntry zipfile (str filename ".xml"))
         in (.getInputStream zipfile zipentry)] 
     (slurp in)))

Answer 2

MusicXML's zip structure for .mxl files is similar to that of the EPUB format. See http://www.musicxml.com/tutorial/compressed-mxl-files/zip-archive-structure/ in the MusicXML tutorial for more information about where to find the XML score data within the MXL archive.

Answer 3

if someone stumbles upon this, and can't figure out how to unzip the compressed mxl file:

on mac, I just renamed it to .zip and it worked out fine!