parsing - How to implement command-line variables in Xtext -

i want domain specific language (dsl) accept command-line arguments variables in bash scripts. example: user might issue command runmydsl mydslfile.dsl -args 10 15 or runmydsl mydslfile.dsl -nvargs arg1=10 arg2=15. capture these values variables $1, $2 first command or $arg1, $arg2 second command. these variables can treated other read-only variables in dsl:

val somevariable = $1 

since new xtext/parser field, looking best practices people follow dealing situation. simplicity, let's assume, working on simplified dsl addition (based on expression language described in http://blog.efftinge.de/2010/08/parsing-expressions-with-xtext.html):

expression : variable '+' variable; variable: ('val' id '=' int) | commandlinevariable; commandlinevariable: ??; 

my first idea following:

1.) parse dsl file , access ast, store refence in locally definded variable of corresponding eclass.

2.) use 'mydslfactory' class create new 'variable' instance, set value, given command line , put somewhere ast.

to should define attribute names in 'variable' parser rule:

variable: 'val' name=id '=' value=int; 

'variable' creation (more or less):

variable newvar = mydslfactory.einstance.createvariable(); newvar.setname(args[2].split("=")[0]); newvar.setvalue(new integer(args[2].split("=")[1])); 

then put ast , modified ast either create temporary dsl file processed before or process ast directly.