|
package java_cup;
|
|
import java.util.Enumeration;
|
|
/** 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.
|
*
|
* @see java_cup.parse_action
|
* @see java_cup.parse_action_row
|
* @version last updated: 11/25/95
|
* @author Scott Hudson
|
*/
|
public class parse_action_table {
|
|
/*-----------------------------------------------------------*/
|
/*--- Constructor(s) ----------------------------------------*/
|
/*-----------------------------------------------------------*/
|
|
/** 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.
|
*/
|
public parse_action_table()
|
{
|
/* 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();
|
}
|
|
/*-----------------------------------------------------------*/
|
/*--- (Access to) Instance Variables ------------------------*/
|
/*-----------------------------------------------------------*/
|
|
/** How many rows/states are in the machine/table. */
|
protected int _num_states;
|
|
/** How many rows/states are in the machine/table. */
|
public int num_states() {return _num_states;}
|
|
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
|
|
/** Actual array of rows, one per state. */
|
public parse_action_row[] under_state;
|
|
/*-----------------------------------------------------------*/
|
/*--- General Methods ---------------------------------------*/
|
/*-----------------------------------------------------------*/
|
|
/** 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.
|
*/
|
public void check_reductions()
|
throws internal_error
|
{
|
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++;
|
}
|
}
|
}
|
}
|
|
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*
|
|
/** Convert to a string. */
|
public 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 += col + ":" + under_state[row].under_term[col] + " ";
|
|
/* end the line after the 3rd one */
|
cnt++;
|
if (cnt == 3)
|
{
|
result += "\n";
|
cnt = 0;
|
}
|
}
|
}
|
/* finish the line if we haven't just done that */
|
if (cnt != 0) result += "\n";
|
}
|
result += "------------------------------";
|
|
return result;
|
}
|
|
/*-----------------------------------------------------------*/
|
|
};
|
