JavaCommandrunner36

A small, retro-ish (runs on JDK 1.6) Java program for running commands to spawn processes and other suchlike in a more platform-agnostic way than $SHELL allows.

Command syntax:

jcr:docmd [<option> ...] [<var>=<value> ...] [--] <program> [<arg> ...]

When run on the command-line, jcr:docmd is implied.

Conceptual Model

In a command like jcr:print foo bar, jcr:print names a JCRProcedure, while the whole string represents a JCRCommand.

• A JCRProcedure can be thought of as a function of the remaining arguments which returns a JCRCommand
• A JCRCommand can be thought of as a function of the mapping of environment variable names to values which returns a JCRAction
• A JCRAction describes a procedure to be run, including information on how its IO streams should be configured based on the environment.
• A JCRProcess is the instantiation of a JCRAction. While running, a JCRProcess can read and write from its IO streams and otherwise interact with the environment. When it finishes, it returns an int32 exit code. Each JCRProcess runs exactly once.

In other words:

# Mapping command strings to commands can be throught of as a purely
# functional operation:
JCRProceduire = (argv : List<String>) -> JCRCommand
JCRCommand    = (environment : Map<String,String>) -> JCRAction

# Instantiating and running a process are not pure functions:
startProcess(action : JCRAction, io : List<IO>) -> JCRProcess
waitForProcess(process : JCRProcess) -> Int32

To keep things simple, the current implementation does not separate these steps (as of v36.1.24, everything from parsing the command to waiting for the process to complete is done at once by SimplerCommandRunner#doJcrDoCmd et al), but the conceptual model is documented here for the sake of alternative methods of constructing commands and actions.

For starters, it may be reasonable to allow some procedures to take more structured arguments, e.g. so that sub-commands can be unambiguously represented.

Commands / 'action constructors'

| Default | |

alias	Full name
jcr:docmd	http://ns.nuke24.net/JavaCommandRunner36/Action/DoCmd
jcr:exit	http://ns.nuke24.net/JavaCommandRunner36/Action/Exit
jcr:print	http://ns.nuke24.net/JavaCommandRunner36/Action/Print
jcr:runsys	http://ns.nuke24.net/JavaCommandRunner36/Action/RunSysProc