Creating Shell Scripts with Maple

I write shell scripts that call Maple to automate frequent tasks. Because I prefer writing Maple code to shell code, I've created a Maple package, Bark, that generates a shell script from Maple source code. It provides a compact notation for defining both optional and positional command-line parameters, and a mechanism to print a help page, from the command-line, for the script. The optional parameters can be both traditional single letter Unix options, or the more expressive GNU-style long options.

As an example, here is the Maple code, using Bark, for a hello-world script.

hello := module()
    Parser := Bark:-ArgParser(NULL
                              , 'prologue' = ( "Print `Hello, World!'" )
                              , 'opts' = ['help' :: 'help' &c "Print this help page"]
    ModuleApply := proc(cmdline :: string := "")
        Bark:-ArgParser:-Parse(Parser, cmdline);
        Bark:-printf("Hello, World!\n");
    end proc;
end module:

The following command creates and installs the shell script in the user's bin directory.

Bark:-CreateScript("hello", hello
                   , 'add_libname' = Bark:-SaveLib(hello, 'mla' = "hello.mla")

The hello script is executed from the command-line as

$ hello
Hello,  World!

Pass the -h (or --help) option to display the help.

$ hello -h
Usage: hello [-h|--help] [--]

Print `Hello, World!'

Optional parameters:
-h, --help Print this help page

CreateScript creates two files that are installed in the bin directory: the shell script and a Maple archive file that contains the Maple procedures. The shell script passes its argument in a call to the parser (a Maple procedure) saved in the archive file (.mla file). Here's the created shell script for the hello command:

#!/usr/bin/env sh
CMD_LINE=$(echo $0; for arg in "$@"; do printf '%s\n' "$arg"; done)
echo "hello(\"$CMD_LINE\");" | "$MAPLE" -q -w2 -B --historyfile=none -b '/home/joe/bin/hello.mla'

I've used Bark on Linux and Windows (with Cygwin tools). It should work on any unix-compatible OS with the Bash shell. If you use a different shell that does not work with it, let me know and I should be able to modify the CreateScript command to have options for specific shells.


Bark is available on the MapleCloud. To install it, open the MapleCloud palette in Maple, select packages in the drop-down menu and go to the New tab (or possibly the Popular tab). You will also need the TextTools package which is also on the MapleCloud. The intro page for Bark has a command that automatically installs TextTools. Alternatively, executing the following commands in Maple 2017 should install both TextTools and Bark.


The source for a few useful scripts are included in the examples directory of the installed Bark toolbox. Maple help pages are included with Bark, use "Bark" as the topic.

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