Running MrEd for the First Time

When MrEd starts up, a console window containing a Scheme read-eval-print loop appears. To evaluate an expression, type it after the prompt and hit return. Re-evaluate old expressions by moving the caret to the end of the expression and hitting return (or by using Meta-P from the current prompt). Evaluate a subexpression by hiliting it and hitting return. To stop evaluation, hold down ctl-shift-c (X Windows and Windows) or cmd-. (MacOS).

To open a text-editing window from the console, use the File New or File Open... menu items.

MrEd's language contains MzScheme (except that it is defaultly case-sensitive); the libraries core.ss and cmdline.ss have been loaded from MzLib, and all of the wx: and mred: names in described in this manual are present.

When MrEd starts up, it looks for a user-specific startup file as described in Startup Sequence. If such a file exists, it is loaded (as a Scheme file) before the console is opened. Preferences about the appearance and behaviour of MrEd can be set using the File Preferences... menu item.

MrEd needs at least these three directories to startup: the system collection directory, the mred collection directory, and the mzlib collection directory. These directories are usually in a collects directory within the distribution plt directory. More generally, a collection directory is found in any directory specified by the current-library-collection-paths MzScheme parameter (see library collections).