The Omegahat Script

Any existing elements in the environment variable CLASSPATH are prepended to the value constructed in the script and passed to the JVM via the -classpath argument.

If the environment variable OMEGA_DEVELOPER is not set, and the file Jars/Omegahat/Environment.jar exists, then this is used as the source of the classes in the omegahat package. Other Jar files in the Jars/Omegahat/ directory will also be added to the classpath.

-i fully qualified class

a different Java application class (containing a static main) is invoked by specifying the toplevel class via the -i argument e.g.

          omegahat -i org.omegahat.environment.GUI.omega
      

The argument specifies the Java class to use as the one providing the entry point \JMethod{main}. This allows a variety of different applications and interfaces to be instantiated from this common \OMega{} script. The class must be fully specified as package and class name and must be resolvable from the classpath supploeed to the JVM. \\

-ix class name

A simplified version of the -i flag, allowing one to specify an partially qualified class name within the org.omegahat package. e.g.

      omegahat -ix omega

The -ix flag is the same as -i except it does not require a fully qualified classname, but instead will locate the class within the org.omegahat tree in the same way that classes are located within the language.

This flag will only work when we are running from non-Jar files for the environment. It uses the expandOmegaClass perl script.

-c file name

allows a different configuration file to be used for the evaluator (other than OmegaOptions).

-s script name

specifies the full name of a file containing Omegahat commands that are run a single time at the beginning of the session. The default is the script OmegaInit. The file is located using the FileLocator class parameterized by the searchPath property in the configuration file.

-v

The -verbose flag causes information from this script to be written to the terminal. This includes settings for the variables OMEGA_HOME, the classpath, the final command that is executed by the script and so on. This information is useful for debugging settings controlling the invocation of the Omegahat session. It should be added to bug reports

-verbose

The -verbose has the same effect as the -v flag and additionally is also passed to the JVM causing it to display a lot of information regarding the loading of classes and their origin, etc.

-verify

The -verify flag causes the Java virtual machine to "verify" all classes as they are loaded, including those usually trusted from disk. This checks that all classes are valid. This is useful for debugging dynamically compiled classes via the Jas package.

The -verbose and -verify arguments are simple boolean flags and do not take a second argument as a value.

-u

This avoids the default behavior of source'ing the users initialization script, $HOME/.omegahatrc. This takes no value.

+u filename

identifies a file (that is located using the file location mechanism of the default evaluator) that is treated as an Omegahat script that is source'd by the default initialization scripts (OmegaInit).

-e full class name

specifies the fully qualified name of a class to use when creating an evaluator. E.g.

         omegahat -e org.omegahat.Interfaces.CORBA.Parser.OrbacusEvaluator
      

(See also -CORBA

-ex

specifies a partially qualified class name to use when creating an evaluator. This is to -e as -ix is to -i.

-help

displays a brief description of these arguments.

-CORBA

(takes no argument.) Use a CORBA aware evaluator & parser which allows calls of the form

          x.foo(a,b)
      

to be interpreted as remote method calls on a server x made available as an Omegahat variable from the naming service. Appends the CORBA packages to the classpath.

-w

sets a property UseGUI in the System level properties. The initialization scripts check for the presence of this (currently not the actual value) and creates a splash screen accordingly. To run the GUI interface version of Omegahat, use

     omegahat -ix GUI.omega
    

-xp

Force all the Jar files in the the directory $OMEGA_HOME/Jars/Omegahat to be included in the classpath, ahead of the regular system classpath files. This allows one to put add-on packages there and have them automatically included. Note that this applies only to jar files, and not directories.

-Dname=value

passed directly to the JVM, specifying a system property named name with value value.

-X

pass the entire argument as a non-standard argument of the JVM. This is used for profiling, setting certain characteristics of the JVM, etc.

-Jarg

pass the entire argument directly to the JVM unaltered, i.e. with the -J prefix still present. These can be used to control initialization and run-time parameters of the VM such as maximum memory size, initial heap size, etc. See the documentation for the JVM.

--home

Instruction to print the value of the environment variable OMEGA_HOME and exit. This is used in autoconf and other configuration tools for computing the location of the distribution and hence where classes, help files, C/C++ libraries, etc. are located.

--

all arguments after this are not processed by this script but passed directly to the Java application being invoked. This effectively escapes arguments from this script and allows them to be interpreted by the application. This allows an application to have arguments that are also arguments to this script.

Properties