README.ensemble

An ensemble is a single command that can dispatch subcommands
to other commands.

For example [string] is a built-in ensemble.

The ensemble command allows an ensemble command to be created
that redirects to other commands.

Create an ensemble by having multiple commands that all share
the same prefix. For example:

proc {test open} {name} { ... }
proc {test close} {handle} { ... }
proc {test show} {handle} { ... }

Then simply:

ensemble test

Now a new command, test, is created that will invoke the other commands
based on the first argument. For example:

set h [test open file.txt]
test show $h
test close $h

By default ensemble expects the commands to be named "<name> ". If another
prefix is used, this can be specified with the -automap option. e.g.

ensemble test -automap test.

This could be used if the commands were named test.open, test.close, test.show

Note that ensembles are dynamic, not fixed at the point of creation.
This means, for example, that we can can create a new commands, "test reverse"
after the ensemble has been created and it can still be invoked as test reverse ...

It is easy to create an ensemble for commands in a namespace by simply using
-automap <ns>:: however for compatibility with Tcl, 'namespace ensemble create' is provided
that does with when invoked within a namespace. e.g.

namespace eval test {
	namespace ensemble create

	proc open {name} { ... }
	proc close {handle} { ... }
	proc show {handle} { ... }
}

test open file.txt