+-----------------------------------------------------------------+
|                                                                 |
|  This file delineates how to use the Command Line Environment.  |
|                                                                 |
+-----------------------------------------------------------------+

After compilation (see Build.README), the Command Line Environment can
be started with the command 'cle'. Note that your PATH environment
variable must include the 'bin' directory of the AspOEv framework, or
'%ASPOEV_HOME%\bin'.

+-------------------------+
| Running Vejal programs: |
+-------------------------+
Vejal programs can be run from the command line environment with the
'run' command. If the Vejal program has already been loaded, simply
specify the name of the type whose 'main' method should be
executed. If the Vejal program is not already loaded, specify the name
of the file containing the program omitting the '.vj' extension
(Currently the file must be in the base Vejal directory,
i.e. '%ASPOEV_HOME%\vejal') - the run command attempts to parse and
execute the contents, starting with the 'main' method.

e.g.

AspOEv> run Foo;

-or-

AspOEv> run Foo<x.x>;

The run command creates a separate execution environment in the Vejal
interpreter (via a new Java Thread). However, currenly, the spawned
execution environment and program outputs to the command line from
which it was created.

+--------------------+
| Supplied commands: |
+--------------------+
The command line environent needs few specially defined commands, as
it accepts and executes any valid Vejal statement. Supplied commands
do not require semi colon termination, unlike Vejal
statements. Supplied commands are:

vars - display all visible variables in the environment
types - display all types loaded into the interpreter
bye / exit - quit the command line environment
help - print help message
help -edit - print help message about primitive declarations

+-------------------+
| Vejal Statements: |
+-------------------+
The command line environment parses and executes all valid Vejal
syntax, and subsequently echos the value of the statement. If the
value of the statement is a Vejal MetaObject or a POJO, the toString
method is executed on the object and printed.

e.g.

AspOEv> vars

Visible variables:

     double foo;
     JavaObject SchemaManager;
     JavaObject InstanceAdapter;
     JavaObject Runtime;
     . . .

AspOEv> foo;          // Vejal statement
6.0                   // value of 'foo'
AspOEv> SchemaManager;
ContextVersioningManager {        // toString for 'SchemaManager'
   Context { InsuranceCompany }
   Context { Physician, Nurse }
}
AspOEv>

Valid Vejal statements include everything from assignment to 'while'
loops, however, multiple line command do have some special
requirements for parsing.

+-------------------------+
| Multiple line commands: |
+-------------------------+
Multiple line vejal statements can also be executed on the command
line, however, these statements must be wihin a Vejal block. Also, the
commands must end in '};' (the end of the vejal block, and a semi
colon to indicate the end of the command).

e.g.

AspOEv> if (false) {            // multiple line command
	  print("true!");
        }
        else {
          print("false!");
        };
false!                          // output
AspOEv>

Note that without the trailing semi colon, there would be a conflict
in parsing the above statement at the terminal '}' to the 'if'
block. (The command line environment would not know when you were done
inputing the command, and would have simply executed the 'if'
statement)

+--------------------------------+
| Changing evolution strategies: |
+--------------------------------+
Evolution strategies (Schema management and instance adaptation) are
introduced as global variables ('SchemaManager' and 'InstanceAdapter'
respectively) in the AspOEv interpreter. This means that they are
accessible from all execution environments, and can be changed via a
simple assignment statement.

e.g.

AspOEv> SchemaManager = new aspoev.manager.schema.SchemaModificationManager();

-or-

AspOEv> InstanceAdapter = new aspoev.manager.adapter.UpdateBackdateAdapter();

Transition between schema managers can be achieved by storing the
Schema Extent of the previous strategy and calling the
'transitionFrom' method on the new schema manager. A schema manager's
schema extent is stored in the global variable SchemaExtent'.

e.g.

AspOEv> SchemaExtent oldSchema = SchemaExtent;

AspOEv> SchemaManager = new SomeSchemaManagementStrategy();

AspOEv> SchemaManager.transitionFrom(oldSchema);