The LARA interpreter is a tool able to interpret an Aspect-IR and execute its aspects. larai, in its basis, can execute any arbitrary imperative code and execute tools and commands that are not part of larai. However, this interpreter cannot carry out weaving-related tasks, such as selecting points in the code and apply actions. In order to do so, larai can be connected to a [lara:docs:weavingengine|weaving engine] that is responsible of parsing the target source code, select join points and retrieve attribute information, apply actions, and generate the resulting code.

larai as a standalone has been used for different purposes:

• As scripting language
• Tools execution
• Coordination of a compilation flow (e.g. instrumentation→optimization→compilation→execution→profile).
• Design-space exploration (e.g. using previous objective)

NOTE: larai has a builtin larac, meaning that larac is not required as a separated tool for lara→Aspect-IR compilation and hence a .lara file may be given as input argument of larai.

This interpreter may be executed in two different ways: by command line for immediate execution of a lara file or by an IDE for developing and execute/test aspects.

larai is an executable jar file (download here) that always expects a .lara|.xml file as the first input argument and has a set of optional arguments. If a .lara file is given then larac is automatically executed, otherwise, if a .xml is given, the interpreter assumes that file as the Aspect-IR and attempts to execute. larai accepts the options defined in the following table. A special note must be given to the last option as this option is not actually an option of larai but to portray an additional option that a weaving engine may contain. These additional options always have a short option defined in uppercase to differ to *larai* options.

usage: <aspect.lara> [options] [-c <file>]  | -c <file>[-g]
 -c,--config <file>              configuration file with defined options
 -g,--gui                        open in GUI mode
 -h,--help                       print this message
 -v,--version                    print version information and exit
 -av,--argv <arguments>          arguments for the main aspect
 -m,--main <aspect>              select main aspect
 -d,--debug                      show all process information
 -o,--output <dir>               change output dir
 -p,--workspace <dir>            change the working directory
 -b,--verbose <level>            verbose level
 -t,--tools <tools.xml>          location of the tools description
 -r,--report <file_name.json>    Output file for the main aspect, in JSON
                                 format
 -i,--includes <dir>             includes folder (imports files with
                                 extensions: lara, jar, js, class)
 -j,--javascript                 show the javascript output in the same
                                 stream as the application's output
 -l,--log <fileName>             outputs to a log file
 -e,--metrics <file_name.json>   Output file for the weaving metrics
 -O, --other                     An option related to a specific weaving engine

The following table provides a further explanation of the larai options. Note that option -g (GUI mode) can only be used with -c (config file) option and without specifying a lara file.