At heart the program is a text editor; it works just like any other text editor - it will open multiple files in separate windows, and let you copy and paste text Between them. It has all the usual editing commands, Cut, Copy, Paste, Clear and Undo plus Search/Replace and there's also a routine to recursively search through all the text files and folders in a directory. It can work with megabyte-sized files (if you have enough memory), and you can use it for pretty much anything you would normally do with a text editor. (I'm writing the HTML source for these pages using it - isn't that incestuous?)
If the text being edited contains abc tunes, however, a whole array of different options becomes available. The tunes can be embedded in ordinary text, as the program locates them by looking for the X: field. It considers the tune to end at the first blank line following the K: field, and ignores any text in between tunes. When opening files it counts the tunes present and displays the number at the top of the window. You select a tune by placing the text insertion point anywhere within it. You can then perform various operations on it, for example play it. Tunes play in the background, so you can go on editing the file while a tune is playing, and even edit the tune which is actually playing, although changes which you make will not be audible until the next time you play it.
Features: Now compatible with OS 10.5.2. Fixed a couple more bugs in Expand Guitar Chords. Fixed a bug which prevented intonations from working properly. Fixed a bug which caused the Recent Files menu to be cleared if the user saved a file without resources. Fixed a bug which caused files to fail to open if they contained bad symbol or macro definitions in the file header. Fixed a bug which sometimes caused the Transpose routine to put the key signature in lower-case. Fixed a bug which caused a crash when importing MusicXML under recent versions of OS X. Changed the menu short