MrEd accepts a number of command-line flags.
Under Mac OS Classic, a user can specify command-line flags by holding down the Command key while starting MrEd, which provides a dialog for entering the command line. Dragging files onto the MrEd icon in Mac OS Classic is equivalent to providing each file's name on the command line preceded by -f, so each file is loaded after MrEd starts. When files are dragged onto MrEd with the Command key pressed, the command line specified in the dialog is appended to the implicit command-line for loading the files.
Under Mac OS X, a leading flag of the form -psn_ is treated specially. It indicates that Finder started the application, so the current input, output, and error output are redirected to a GUI window.
MrEd accepts the following flags (in addition to the X-specific flags described in X Window System Flags):
Startup file and expression flags:
file or --script
file : Use this flag for MrEd-based scripts. It mutes the
startup banner printout, suppresses the graphical
file after MrEd starts. No argument after
treated as a flag. The -r or --script flag is a
shorthand for -fmv-.
file or --script-cd
file : Same as -r
file or --script
file, except that the current directory is changed to
file's directory before it is loaded. The -i or
--script-cd flag is a shorthand for -dmv-.
-z or --stdio : Calls
graphical-read-eval-print-loop, and also prints
version information to stdout.
-Z or --nogui : Skips the
( on startup. Also skips
lib "mred.ss" "mred")
m : Loads code embedded in
the executable from file position
m after MrEd
starts. This flag is useful for creating a stand-alone binary by
appending code to the normal MrEd executable. See PLT mzc: MzScheme Compiler Manual
for more details.
-C or --main : Like -r,
then calls the function bound to
main in the top-level
environment. The argument to
main is a list of immutable
strings; the first string is the path of the file that was loaded,
and the rest of the list contains leftover command-line arguments
(the ones installed in
main function is called only if no previous evaluations or
loads resulted in an uncaught exception.
Language setting flags:
-V or --no-yield : Suppresses the
file or --restore
file : Restores a saved image (see
Images, section 14.8 in PLT MzScheme: Language Manual). Extra
file are returned as a vector of strings to
the continuation of the
write-image-to-file call that
created the image.
Extra arguments following the last flag are available from the
current-command-line-arguments parameter (see
Images, section 220.127.116.11 in PLT MzScheme: Language Manual)
as an immutable vector of immutable strings. The name used to start
MrEd is available from the
(see Images, section 11.3.1 in PLT MzScheme: Language Manual)
'exec-file. In addition, unless -A is specified,
the argument vector is put into the global variable
and the name used to start MrEd is put into the global variable
program as an immutable string.
Multiple single-letter flags (the ones preceded by a single dash) can be collapsed into a single flag by concatenating the letters, as long as the the first flag is not --. The arguments for each flag are placed after the collapsed flags (in the order of the flags). For example,
file -m -e
are equivalent. If a collapsed -- appears before other collapsed flags, it is implicitly moved to the end of the collapsed set.
If the MrEd executable is given a name of the form
dialect, then the command line is effectively
-qAeC '(require (lib "init.ss" "script-lang" "
The first actual command-line argument thus serves as a file to
load. The file is loaded into a namespace that is initialized by the
dialect-specific init.ss library. The loaded file should
main, which is called with command-line
arguments -- starting with the loaded file name -- as a list of
current-library-collection-paths parameter is
initialized (as described in
Library Collections and
MzLib, section 16 in PLT MzScheme: Language Manual) before any expression or file is evaluated or
loaded, unless the -x or --no-lib-path flag is specified.
Unless the -q or --no-init-file flag is specified, a user
initialization file is loaded after
current-library-collection-paths parameter is initialized and
before any other expression or file is evaluated or loaded. The path
to the user initialization file is obtained from MzScheme's
find-system-path procedure using
Expressions and files are evaluated and loaded in order that they are provided on the command line, including calls to main implied by --main, embeddings loaded by -k, and so on. If an uncaught exception occurs, the remaining expressions and files are skipped. The thread that loads the files and evaluates the expressions is the main thread. When the main thread terminates (or is killed), the MrEd process exits. The main thread is also the handler thread of the initial eventspace.
After the command-line files and expressions are loaded and evaluated,
the main thread calls
graphical-read-eval-print-loop, unless the -v,
--version, -r, --script, -i, or
--script-cd flag is specified. The -z or
--stdio flag also suppresses the call to
graphical-read-eval-print-loop, but it
read-eval-print-loop, instead. (The other flags, such as -v, have
no effect on this call to
Finally, after the command-line files and expressions are loaded and
evaluated, and after
read-eval-print-loop is called, the main
(yield 'wait). The -V or --no-yield
flag suppresses this call to
The exit status for the MrEd process indicates an error if an error
occurs evaluating or loading a command-line expression or file and
graphical-read-eval-print-loop is not called afterwards, or if the default exit handler
is called with an exact integer between 1 and 255.
Evaluating command-line expressions with -f or -v is
different from evaluating the same expressions within the window
graphical-read-eval-print-loop window creates a new
eventspace (and thus a new thread) for evaluating expressions entered
into the window. One consequence of this convention is that
terminating the evaluation thread (e.g., with
(current-thread))) does not cause MrEd to exit, because the
evaluation thread is not MrEd's main thread.18
In contrast, MzScheme's
read-eval-print-loop always evaluates expressions
within the thread that calls
read-eval-print-loop. Using the -z or
--stdio flag calls
read-eval-print-loop in the main thread, so
(kill-thread (current-thread)) in that case does exit MrEd.
Furthermore, the main thread is the handler thread for the initial
eventspace; thus, windows created in
read-eval-print-loop without changing the
eventspace never receive events unless
(yield) is called
MrEd creates an initial eventspace, and the handler thread for the eventspace is MrEd's main thread; if the thread is killed, then the MrEd process exits.
Under Unix/X, the following standard X Window System flags are recognized (but not necessarily implemented): -display (1 argument), -geometry (1 argument), -bg (1 argument), -background (1 argument), -fg (1 argument), -foreground (1 argument), -fn (1 argument), -font (1 argument), -iconic (0 arguments), -name (1 argument), -rv (0 argument), -reverse (0 arguments), +rv (0 arguments), -selectionTimeout (1 argument), -synchronous (0 arguments), -title (1 argument), -xnllanguage (1 argument), and -xrm (1 argument).
All X flags must precede all other flags and arguments.
18 However, the
exit handler is not changed, so evaluating
(exit) does exit
MrEd unless the exit handler is changed before calling