parse_action_tablepublic class parse_action_table extends Object | This class represents the complete "action" table of the parser.
It has one row for each state in the parse machine, and a column for
each terminal symbol. Each entry in the table represents a shift,
reduce, or an error. |
| Fields Summary |
|---|
| protected int | _num_statesHow many rows/states are in the machine/table. | | public parse_action_row[] | under_stateActual array of rows, one per state. |
| Constructors Summary |
|---|
public parse_action_table()Simple constructor. All terminals, non-terminals, and productions must
already have been entered, and the viable prefix recognizer should
have been constructed before this is called.
/* determine how many states we are working with */
_num_states = lalr_state.number();
/* allocate the array and fill it in with empty rows */
under_state = new parse_action_row[_num_states];
for (int i=0; i<_num_states; i++)
under_state[i] = new parse_action_row();
|
| Methods Summary |
|---|
| public void | check_reductions()Check the table to ensure that all productions have been reduced.
Issue a warning message (to System.err) for each production that
is never reduced.
parse_action act;
production prod;
/* tabulate reductions -- look at every table entry */
for (int row = 0; row < num_states(); row++)
{
for (int col = 0; col < under_state[row].size(); col++)
{
/* look at the action entry to see if its a reduce */
act = under_state[row].under_term[col];
if (act != null && act.kind() == parse_action.REDUCE)
{
/* tell production that we used it */
((reduce_action)act).reduce_with().note_reduction_use();
}
}
}
/* now go across every production and make sure we hit it */
for (Enumeration p = production.all(); p.hasMoreElements(); )
{
prod = (production)p.nextElement();
/* if we didn't hit it give a warning */
if (prod.num_reductions() == 0)
{
/* count it *
emit.not_reduced++;
/* give a warning if they haven't been turned off */
if (!emit.nowarn)
{
System.err.println("*** Production \"" +
prod.to_simple_string() + "\" never reduced");
lexer.warning_count++;
}
}
}
| | public int | num_states()How many rows/states are in the machine/table.return _num_states;
| | public java.lang.String | toString()
String result;
int cnt;
result = "-------- ACTION_TABLE --------\n";
for (int row = 0; row < num_states(); row++)
{
result += "From state #" + row + "\n";
cnt = 0;
for (int col = 0; col < under_state[row].size(); col++)
{
/* if the action is not an error print it */
if (under_state[row].under_term[col].kind() != parse_action.ERROR)
{
result += " [term " + col + ":" + under_state[row].under_term[col] + "]";
/* end the line after the 2nd one */
cnt++;
if (cnt == 2)
{
result += "\n";
cnt = 0;
}
}
}
/* finish the line if we haven't just done that */
if (cnt != 0) result += "\n";
}
result += "------------------------------";
return result;
|
|
