Running MrEd

MrEd accepts a number of command-line flags. Under MacOS, 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 MacOS 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.

MrEd accepts the following flags (in addition to the X-specific flags described in X Window System Flags):

• Startup file and expression flags:

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  -e expr : Evaluates expr after MrEd starts.

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  -f file : Loads file after MrEd starts.

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  -d file : Uses load/cd to load file after MrEd starts.

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  -F : Loads each remaining argument as a file after MrEd starts.

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  -D : Loads each remaining argument as a file using load/cd after MrEd starts.

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  -l file : Loads the MzLib library file after MrEd starts.

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  -L file collect : Loads the library file in the collection collect after MrEd starts.

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  -r file or --script file : Use this flag for MrEd-based scripts. It mutes the startup banner printout, suppresses the graphical read-eval-print loop, and loads file after MrEd starts. No argument after file is treated as a flag. The -r or --script flag is a shorthand for -fmv-.

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  -i 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-.

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  -z or --stdio : Calls read-eval-print loop (using the current input and output), and supresses the graphical read-eval-print loop. The -z or --stdio flag is shorthand for -ve "(read-eval-print-loop)".

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  -w or --awk : Loads the awk.ss library after MrEd starts.

• Initialization flags:

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  -x or --no-lib-path : Suppresses the initialization of current-library-collection-paths (as described in Library Collections and MzLib).

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  -q or --no-init-file : Suppresses loading the user's initialization file, as described below.

• Language setting flags:

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  -g or --case-sens : Creates an initial namespace where identifiers and symbols are case-sensitive.

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  -c or --esc-cont : Creates an initial namespace where call-with-current-continuation and call/cc capture escape continuations (like call/ec) instead of full continuations.

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  -s or --set-undef : Creates an initial namespace where set! will sucessfully mutate an undefined global variable (implicitly defining it).

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  -a or --no-auto-else : Creates an initial namespace where falling through all of the clauses in a cond or case expression raises the exn:else exception.

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  -n or --no-key : Creates an initial namespace where keywords are not enforced.

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  -y or --hash-percent-syntax : Creates an initial namespace that includes only the #% syntactic forms.

• Miscellaneous flags:

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  - : No argument following this flag is used as a flag.

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  -m or --mute-banner : Suppresses the startup banner text.

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  -v or --version : Suppresses the graphical read-eval-print loop.

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  -h or --help : Shows information about MrEd's command-line flags and then exits; ignoring other flags.

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  -p or --persistent : Catches the SIGDANGER (low page space) signal and ignores it (AIX only).

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  -Rfile or --restore file : Restores a saved image (see Images). Extra arguments after 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 put into the Scheme global variable argv as a vector of strings. The name used to start MrEd is put into the global variable program as a 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,

  -vfme file expr 

  -v -f file -m -e expr 

The current-library-collection-paths parameter is initialized (as described in Library Collections and MzLib) 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 'init-file.

Expressions and files are evaluated and loaded in order that they are provided on the command line. The thread that loads the files and evaluates the expression 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, --script-cd flag is specified. The -z or --stdio flag also suppresses the call to graphical-read-eval-print-loop, but it calls read-eval-print-loop, instead. (The other flags, such as -v, have no effect on this call to read-eval-print-loop.)

Evaluating command-line expressions with -f or -v is different from evaluating the same expressions within the window provided by graphical-read-eval-print-loop. The 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 (kill-thread (current-thread))) does not cause MrEd to exit, because the evalaution thread is not MrEd's main thread. 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 explicitly.

• X Window System Flags
• Initial Eventspace