I'm working through the PragProg Core Data book, and have encountered an issue passing contextInfo to NSOpenPanel.beginSheetForDirectory This issue was discussed on the list previously by Dr. Nic: http://www.mail-archive.com/macruby-devel@lists.macosforge.org/msg00330.html The problem is that there doesn't seem to be a way to cast an object pointer to a void pointer in Macruby, but when openPanel calls the callback assigned in didEndSelector it does cast the pointer passed in contextInfo to a void pointer, leading to a type error when the callback is called: {{{ 2010-01-08 23:44:49.580 GrokkingRecipesRuby[34059:10b] expected instance of Pointer of type `v', got `@' }}} I tried assigning my object to a Pointer.new('^v') and Pointer.new(:uchar) but this also caused type errors. is there any workaround for this? Cheerio, Michael Johnston lastobelus@mac.com