-ref=k
is an ACT command-line option.A Guide to Using ACT Data Structures
Getting Started
Initialization
Act configuration files are read in and any ACT command-line options are parsed and removed from the argument list automatically when the library is initialized as:
Act::Init (&argc, &argv);
where argc
and argv
are the usual command-line options to main()
. This should be the first function call before any other ACT functions are used.
When this call is executed, any configuration files provided on the command-line and the default configuration files are read in and processed to create internal act data structures.
Typically, the next step is to create an Act
pointer to the data structure:
Act *a; a = new Act (argv[1]);
where argv[1]
is the top-level ACT file name. This parses the ACT input file, and creates data structures for all the instances, namespaces, processes, etc. specified in the ACT file.
Referencing a process
Once the Act
pointer has been created, a process (provided in the command-line arguments) within the file can be accessed and expanded (if necessary):
Process *p = a->findProcess (argv[2]); if (!p->isExpanded()) { p = p->Expand (ActNamespace::Global(), p->CurScope(), 0, NULL); }
In this example, the assumption is that argv[2]
holds a string that corresponds to the process name.
Referencing the languages body
The languages body can be accessed from the process pointer:
act_languages *lang; lang = p->getlang();
This provides access to all the sub-languages specified within the process.1)
Referencing a particular language body
A language body can be accessed from the languages pointer. For example, for the chp body:
act_chp *chp; chp = lang->getchp();
Note that the chp
pointer will be NULL if there is no CHP sub-language specified within the process definition.
Finally, to get a pointer to the actual object that stores the CHP data structure:
act_chp_lang_t *chp_lang; chp_lang = chp->c;
The CHP data structure
The act_chp_lang_t
object is an object of the act_chp_lang
structure (definition in lang.h
). It contains an integer type
, which says what type of ACT_CHP
token it is. Two other members label
and space
are typically NULL
. The final member u
is an object that contains the actual CHP statement. For example, any given u
can be a loop, doloop, assignment statement, communication action, etc. Each of these have their own structure and the object is a union
of these. One of the possibilities: a comma or semicolon separated list of statements is stored as a list_t
linked list semi_comma.cmd
.
The statement list data structure
The linked list list_t
contains elements of type listitem_t
. See list.h
or list.c
for details and available methods. In a CHP data structure, this is used to store lists of statements. To get the actual statement stored in the list of statements, call list_value
on the required listitem_t
of the list:
act_chp_lang_t *c; // contains the overall chp body act_chp_lang_t *stmt; list_t *stmt_list; listitem_t *li; // if c->type is ACT_CHP_SEMI or ACT_CHP_COMMA stmt_list = c->u.semi_comma.cmd; // returns the linked list for (li = list_first (stmt_list); li; li = list_next (li)) { stmt = (act_chp_lang_t *)(list_value(li)); // do something here }