/**
* The main driver for the system.
*
* @param argv an array of strings containing command line arguments.
*/
public static void main(String argv[])
throws internal_error, java.io.IOException, java.lang.Exception {
boolean did_output = false;
start_time = System.currentTimeMillis();
/* process user options and arguments */
parse_args(argv);
/* open output files */
if (print_progress) System.err.println("Opening files...");
open_files();
prelim_end = System.currentTimeMillis();
/* parse spec into internal data structures */
if (print_progress) System.err.println("Parsing specification from standard input...");
parse_grammar_spec();
parse_end = System.currentTimeMillis();
/* don't proceed unless we are error free */
if (lexer.error_count == 0) {
/* check for unused bits */
if (print_progress) System.err.println("Checking specification...");
check_unused();
check_end = System.currentTimeMillis();
/* build the state machine and parse tables */
if (print_progress) System.err.println("Building parse tables...");
build_parser();
build_end = System.currentTimeMillis();
/* output the generated code */
if (print_progress) System.err.println("Writing parser...");
emit_parser();
did_output = true;
emit_end = System.currentTimeMillis();
} else {
/* fix up the times to make the summary easier */
emit_end = parse_end;
}
/* do requested dumps */
if (opt_dump_grammar) dump_grammar();
if (opt_dump_states) dump_machine();
if (opt_dump_tables) dump_tables();
dump_end = System.currentTimeMillis();
/* close output files */
if (print_progress) System.err.println("Closing files...");
close_files();
/* produce a summary if desired */
if (!no_summary) emit_summary(did_output);
}
/**
* Build the (internal) parser from the previously parsed specification. This includes:
*
* <ul>
* <li>Computing nullability of non-terminals.
* <li>Computing first sets of non-terminals and productions.
* <li>Building the viable prefix recognizer machine.
* <li>Filling in the (internal) parse tables.
* <li>Checking for unreduced productions.
* </ul>
*/
protected static void build_parser() throws internal_error {
/* compute nullability of all non terminals */
if (opt_do_debug || print_progress)
System.err.println(" Computing non-terminal nullability...");
non_terminal.compute_nullability();
nullability_end = System.currentTimeMillis();
/* compute first sets of all non terminals */
if (opt_do_debug || print_progress) System.err.println(" Computing first sets...");
non_terminal.compute_first_sets();
first_end = System.currentTimeMillis();
/* build the LR viable prefix recognition machine */
if (opt_do_debug || print_progress) System.err.println(" Building state machine...");
start_state = lalr_state.build_machine(emit.start_production);
machine_end = System.currentTimeMillis();
/* build the LR parser action and reduce-goto tables */
if (opt_do_debug || print_progress) System.err.println(" Filling in tables...");
action_table = new parse_action_table();
reduce_table = new parse_reduce_table();
for (Enumeration st = lalr_state.all(); st.hasMoreElements(); ) {
((lalr_state) st.nextElement()).build_table_entries(action_table, reduce_table);
}
table_end = System.currentTimeMillis();
/* check and warn for non-reduced productions */
if (opt_do_debug || print_progress)
System.err.println(" Checking for non-reduced productions...");
action_table.check_reductions();
reduce_check_end = System.currentTimeMillis();
/* if we have more conflicts than we expected issue a message and die */
if (emit.num_conflicts > expect_conflicts) {
System.err.println(
"*** More conflicts encountered than expected " + "-- parser generation aborted");
lexer.error_count++;
build_end = System.currentTimeMillis();
/* do dumps and summary as needed */
if (opt_dump_grammar) dump_grammar();
if (opt_dump_states) dump_machine();
if (!no_summary) emit_summary(false);
System.exit(100);
}
}