Aliases of the command (without the leading colon), every alias must be unique (this is checked at runtime)
Argument parser function which handles the input given after the repl command
A human-readable description of what the command does
Function to execute when the command is invoked, it must not write to the command line but instead use the output handler. Furthermore, it has to obey the formatter defined in the ReplOutput.
Does the command invoke another script? this is mainly used to automatically generate two separate lists when asking for help
Example of how to use the command, for example :slicer --help
Repl command that uses the FlowrAnalyzer