Marshell

Marshell is a shell that can be used to run marcel instructions, on the fly. It is a Read Eval Print Loop tool.

It is the equivalent of groovysh for Marcel.

This shell supports syntax highlighting and also highlights defined functions/variables.

Global variables

In marshell, you can't have class fields, but you can use global variables. To declare a global variable, just assign to a variable a value, without specifying its type

a = 1 // this will create a global variable a

We didn't declare the variable a. If we were in a regular class/source file this wouldn't compile, but in Marshell this is possible.

The type of the global variable is determined by the value provided, and it can't change type. Meaning that after having defining one, you can't assign to it a value that is of an incompatible type of the one you used when you first assigned it a value.

a = 1

doSomething(a)

a = "2" // Semantic Error: Expected expression of type int but gave String

To explicitly specify the type of the global variable, use the as keyword.

a = [1, 2] as Set<int>

How global variables works

Global variables are variables that are stored in the script's Binding. The means you could also retrieve them/set them using methods like Script.getVariable(name)/Script.setVariable(name, value)

Define functions

Define functions as you would in a Marcel script

Define classes

Define classes as you would in a Marcel script. All defined classes are top-level classes (they are not inner class as they would be in a Marcel script).

Run commands

Marshell has some specific commands make your experience even better.

Use the :help command to see all the commands (marshell-specific instructions) you can run

Import dependencies

You can import dependencies on the fly with the :pull command

marshell:000> :pull com.google.code.gson:gson:2.10.1
marshell:000> :import com.google.gson.Gson
marshell:000> gson = new Gson()

Initialisation script

If you want to always load some data everytime you run marshell, you can create a script in $MARCEL_HOME/marshell/init.mcl.

In this script you can't use commands. If you want to import a dependency/dumbbell, just do it like you would in a normal marcel script (import ... or dumbbell '...')

Marshell initialization scripts

Here are some useful initialization scripts that you can use for your shells. These scripts provide useful methods and utilities to enhance your marshell experience, given a context.

File explorer initializer

With the below script, transform Marshell into a file explorer, with shell-like methods such as cd, ls and a variable pwd to get the current directory.

pwd = System.getProperty("user.home") ? new File(System.getProperty("user.home"))
    // for Marshell android compatibility
    : getVariable<File>('ROOT_DIR')
if (pwd == null) {
  println("WARNING: Couldn't initialise properly pwd")
}
_hint = pwd


fun File cd(String path) {
  File f = pwd.child(path)
  if (!f.exists()) throw new IllegalArgumentException("Directory $f doesn't exists")
  if (!f.isDirectory()) throw new IllegalArgumentException("File $f isn't a directory")
  pwd = f
  _hint = pwd
  return f
}


fun File file(String path) -> pwd.child(path)

fun void ls() {
  File[] files = pwd.listFiles()
  if (files != null) {
    for (File f in files) println("- $f")
  }
}