parse_action_table.rar_action

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; } /*-----------------------------------------------------------*/ };