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
*/
@SuppressWarnings (
{ "all" } )
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 < parse_action_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 )
{
ErrorManager.getManager ().emit_warning (
"*** Production \"" + prod.to_simple_string ()
+ "\" never reduced" );
}
}
}
}
/*****************************************************************************
* . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . /** 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 < parse_action_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;
}
/*-----------------------------------------------------------*/
}