/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Add a transition out of this state to another.
/// </summary>
/// <param name="on_sym">the symbol the transition is under.
/// </param>
/// <param name="to_st"> the state the transition goes to.
///
/// </param>
public virtual void add_transition(symbol on_sym, lalr_state to_st)
{
lalr_transition trans;
/* create a new transition object and put it in our list */
trans = new lalr_transition(on_sym, to_st, _transitions);
_transitions = trans;
}
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Simple constructor.
/// </summary>
/// <param name="shft_to">the state that this action shifts to.
///
/// </param>
public shift_action(lalr_state shft_to)
{
/* sanity check */
if (shft_to == null)
throw new internal_error("Attempt to create a shift_action to a null state");
_shift_to = shft_to;
}
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Simple constructor.
/// </summary>
/// <param name="shft_to">the state that this action shifts to.
///
/// </param>
public shift_action(lalr_state shft_to)
{
/* sanity check */
if (shft_to == null)
{
throw new internal_error("Attempt to create a shift_action to a null state");
}
_shift_to = shft_to;
}
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Simple constructor. Note: this should not be used until the number
/// of terminals in the grammar has been established.
/// </summary>
public parse_reduce_row()
{
/* make sure the size is set */
if (_size <= 0)
{
_size = non_terminal.number();
}
/* allocate the array */
under_non_term = new lalr_state[size()];
}
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Full constructor.
/// </summary>
/// <param name="on_sym"> symbol we are transitioning on.
/// </param>
/// <param name="to_st"> state we transition to.
/// </param>
/// <param name="nxt"> next transition in linked list.
///
/// </param>
public lalr_transition(symbol on_sym, lalr_state to_st, lalr_transition nxt)
{
/* sanity checks */
if (on_sym == null)
throw new internal_error("Attempt to create transition on null symbol");
if (to_st == null)
throw new internal_error("Attempt to create transition to null state");
/* initialize */
_on_symbol = on_sym;
_to_state = to_st;
_next = nxt;
}
/*-----------------------------------------------------------*/
/*--- Static Methods ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Helper routine for debugging -- produces a dump of the given state
/// onto System.out.
/// </summary>
protected internal static void dump_state(lalr_state st)
{
lalr_item_set itms;
lalr_item itm;
production_part part;
if (st == null)
{
System.Console.Out.WriteLine("NULL lalr_state");
return;
}
System.Console.Out.WriteLine("lalr_state [" + st.index() + "] {");
itms = st.items();
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (System.Collections.IEnumerator e = itms.all(); e.MoveNext();)
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
itm = (lalr_item)e.Current;
System.Console.Out.Write(" [");
System.Console.Out.Write(itm.the_production().lhs().the_symbol().name_Renamed_Method());
System.Console.Out.Write(" ::= ");
for (int i = 0; i < itm.the_production().rhs_length(); i++)
{
if (i == itm.dot_pos())
{
System.Console.Out.Write("(*) ");
}
part = itm.the_production().rhs(i);
if (part.is_action())
{
System.Console.Out.Write("{action} ");
}
else
{
System.Console.Out.Write(((symbol_part)part).the_symbol().name_Renamed_Method() + " ");
}
}
if (itm.dot_at_end())
{
System.Console.Out.Write("(*) ");
}
System.Console.Out.WriteLine("]");
}
System.Console.Out.WriteLine("}");
}
/*-----------------------------------------------------------*/
/*--- Constructor(s) ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Full constructor.
/// </summary>
/// <param name="on_sym"> symbol we are transitioning on.
/// </param>
/// <param name="to_st"> state we transition to.
/// </param>
/// <param name="nxt"> next transition in linked list.
///
/// </param>
public lalr_transition(symbol on_sym, lalr_state to_st, lalr_transition nxt)
{
/* sanity checks */
if (on_sym == null)
{
throw new internal_error("Attempt to create transition on null symbol");
}
if (to_st == null)
{
throw new internal_error("Attempt to create transition to null state");
}
/* initialize */
_on_symbol = on_sym;
_to_state = to_st;
_next = nxt;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Produce a (semi-) human readable dump of the complete viable prefix
/// recognition state machine.
/// </summary>
public static void dump_machine()
{
lalr_state[] ordered = new lalr_state[lalr_state.number()];
/* put the states in sorted order for a nicer display */
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (System.Collections.IEnumerator s = lalr_state.all(); s.MoveNext();)
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
lalr_state st = (lalr_state)s.Current;
ordered[st.index()] = st;
}
System.Console.Error.WriteLine("===== Viable Prefix Recognizer =====");
for (int i = 0; i < lalr_state.number(); i++)
{
if (ordered[i] == start_state)
{
System.Console.Error.Write("START ");
}
System.Console.Error.WriteLine(ordered[i]);
System.Console.Error.WriteLine("-------------------");
}
}
/*-----------------------------------------------------------*/
/*--- Static Methods ----------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Helper routine for debugging -- produces a dump of the given state
/// onto System.out.
/// </summary>
protected internal static void dump_state(lalr_state st)
{
lalr_item_set itms;
lalr_item itm;
production_part part;
if (st == null)
{
System.Console.Out.WriteLine("NULL lalr_state");
return ;
}
System.Console.Out.WriteLine("lalr_state [" + st.index() + "] {");
itms = st.items();
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (System.Collections.IEnumerator e = itms.all(); e.MoveNext(); )
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
itm = (lalr_item) e.Current;
System.Console.Out.Write(" [");
System.Console.Out.Write(itm.the_production().lhs().the_symbol().name_Renamed_Method());
System.Console.Out.Write(" ::= ");
for (int i = 0; i < itm.the_production().rhs_length(); i++)
{
if (i == itm.dot_pos())
System.Console.Out.Write("(*) ");
part = itm.the_production().rhs(i);
if (part.is_action())
System.Console.Out.Write("{action} ");
else
System.Console.Out.Write(((symbol_part) part).the_symbol().name_Renamed_Method() + " ");
}
if (itm.dot_at_end())
System.Console.Out.Write("(*) ");
System.Console.Out.WriteLine("]");
}
System.Console.Out.WriteLine("}");
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Equality comparison.
/// </summary>
public virtual bool equals(lalr_state other)
{
/* we are equal if our item sets are equal */
return other != null && items().equals(other.items());
}
/*-----------------------------------------------------------*/
/*--- General Methods ---------------------------------------*/
/*-----------------------------------------------------------*/
/// <summary>Add a transition out of this state to another.
/// </summary>
/// <param name="on_sym">the symbol the transition is under.
/// </param>
/// <param name="to_st"> the state the transition goes to.
///
/// </param>
public virtual void add_transition(symbol on_sym, lalr_state to_st)
{
lalr_transition trans;
/* create a new transition object and put it in our list */
trans = new lalr_transition(on_sym, to_st, _transitions);
_transitions = trans;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Build an LALR viable prefix recognition machine given a start
/// production. This method operates by first building a start state
/// from the start production (based on a single item with the dot at
/// the beginning and EOF as expected lookahead). Then for each state
/// it attempts to extend the machine by creating transitions out of
/// the state to new or existing states. When considering extension
/// from a state we make a transition on each symbol that appears before
/// the dot in some item. For example, if we have the items: <pre>
/// [A ::= a b * X c, {d,e}]
/// [B ::= a b * X d, {a,b}]
/// </pre>
/// in some state, then we would be making a transition under X to a new
/// state. This new state would be formed by a "kernel" of items
/// corresponding to moving the dot past the X. In this case: <pre>
/// [A ::= a b X * c, {d,e}]
/// [B ::= a b X * Y, {a,b}]
/// </pre>
/// The full state would then be formed by "closing" this kernel set of
/// items so that it included items that represented productions of things
/// the parser was now looking for. In this case we would items
/// corresponding to productions of Y, since various forms of Y are expected
/// next when in this state (see lalr_item_set.compute_closure() for details
/// on closure). <p>
/// *
/// The process of building the viable prefix recognizer terminates when no
/// new states can be added. However, in order to build a smaller number of
/// states (i.e., corresponding to LALR rather than canonical LR) the state
/// building process does not maintain full loookaheads in all items.
/// Consequently, after the machine is built, we go back and propagate
/// lookaheads through the constructed machine using a call to
/// propagate_all_lookaheads(). This makes use of propagation links
/// constructed during the closure and transition process.
/// *
/// </summary>
/// <param name="start_prod">the start production of the grammar
/// </param>
/// <seealso cref=" CUP.lalr_item_set#compute_closure
/// "/>
/// <seealso cref=" CUP.lalr_state#propagate_all_lookaheads
///
/// "/>
public static lalr_state build_machine(production start_prod)
{
lalr_state start_state;
lalr_item_set start_items;
lalr_item_set new_items;
lalr_item_set linked_items;
lalr_item_set kernel;
CUP.runtime.SymbolStack work_stack = new CUP.runtime.SymbolStack();
lalr_state st, new_st;
symbol_set outgoing;
lalr_item itm, new_itm, existing, fix_itm;
symbol sym, sym2;
System.Collections.IEnumerator i, s, fix;
/* sanity check */
if (start_prod == null)
throw new internal_error("Attempt to build viable prefix recognizer using a null production");
/* build item with dot at front of start production and EOF lookahead */
start_items = new lalr_item_set();
itm = new lalr_item(start_prod);
itm.lookahead().add(terminal.EOF);
start_items.add(itm);
/* create copy the item set to form the kernel */
kernel = new lalr_item_set(start_items);
/* create the closure from that item set */
start_items.compute_closure();
/* build a state out of that item set and put it in our work set */
start_state = new lalr_state(start_items);
System.Object temp_object;
temp_object = start_state;
System.Object generatedAux = temp_object;
work_stack.Push(temp_object);
/* enter the state using the kernel as the key */
SupportClass.PutElement(_all_kernels, kernel, start_state);
/* continue looking at new states until we have no more work to do */
while (!(work_stack.Count == 0))
{
/* remove a state from the work set */
st = (lalr_state) work_stack.Pop();
/* gather up all the symbols that appear before dots */
outgoing = new symbol_set();
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (i = st.items().all(); i.MoveNext(); )
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
itm = (lalr_item) i.Current;
/* add the symbol before the dot (if any) to our collection */
sym = itm.symbol_after_dot();
if (sym != null)
outgoing.add(sym);
}
/* now create a transition out for each individual symbol */
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (s = outgoing.all(); s.MoveNext(); )
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
sym = (symbol) s.Current;
/* will be keeping the set of items with propagate links */
linked_items = new lalr_item_set();
/* gather up shifted versions of all the items that have this
symbol before the dot */
new_items = new lalr_item_set();
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (i = st.items().all(); i.MoveNext(); )
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
itm = (lalr_item) i.Current;
/* if this is the symbol we are working on now, add to set */
sym2 = itm.symbol_after_dot();
if (sym.Equals(sym2))
{
/* add to the kernel of the new state */
new_items.add(itm.shift());
/* remember that itm has propagate link to it */
linked_items.add(itm);
}
}
/* use new items as state kernel */
kernel = new lalr_item_set(new_items);
/* have we seen this one already? */
new_st = (lalr_state) _all_kernels[kernel];
/* if we haven't, build a new state out of the item set */
if (new_st == null)
{
/* compute closure of the kernel for the full item set */
new_items.compute_closure();
/* build the new state */
new_st = new lalr_state(new_items);
/* add the new state to our work set */
System.Object temp_object2;
temp_object2 = new_st;
System.Object generatedAux2 = temp_object2;
work_stack.Push(temp_object2);
/* put it in our kernel table */
SupportClass.PutElement(_all_kernels, kernel, new_st);
}
else
{
/* walk through the items that have links to the new state */
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (fix = linked_items.all(); fix.MoveNext(); )
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
fix_itm = (lalr_item) fix.Current;
/* look at each propagate link out of that item */
for (int l = 0; l < fix_itm.propagate_items().Count; l++)
{
/* pull out item linked to in the new state */
new_itm = (lalr_item) (fix_itm.propagate_items().Peek(fix_itm.propagate_items().Count - (l + 1)));
/* find corresponding item in the existing state */
existing = new_st.items().find(new_itm);
/* fix up the item so it points to the existing set */
if (existing != null)
fix_itm.propagate_items()[l] = existing;
}
}
}
/* add a transition from current state to that state */
st.add_transition(sym, new_st);
}
}
/* all done building states */
/* propagate complete lookahead sets throughout the states */
propagate_all_lookaheads();
return start_state;
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>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>
/// </summary>
protected internal static void build_parser()
{
/* compute nullability of all non terminals */
if (opt_do_debug || print_progress)
System.Console.Error.WriteLine(" Computing non-terminal nullability...");
non_terminal.compute_nullability();
nullability_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* compute first sets of all non terminals */
if (opt_do_debug || print_progress)
System.Console.Error.WriteLine(" Computing first sets...");
non_terminal.compute_first_sets();
first_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* build the LR viable prefix recognition machine */
if (opt_do_debug || print_progress)
System.Console.Error.WriteLine(" Building state machine...");
start_state = lalr_state.build_machine(emit.start_production);
machine_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* build the LR parser action and reduce-goto tables */
if (opt_do_debug || print_progress)
System.Console.Error.WriteLine(" Filling in tables...");
action_table = new parse_action_table();
reduce_table = new parse_reduce_table();
for (System.Collections.IEnumerator st = lalr_state.all(); st.MoveNext(); )
{
lalr_state lst = (lalr_state) st.Current;
lst.build_table_entries(action_table, reduce_table);
}
table_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* check and warn for non-reduced productions */
if (opt_do_debug || print_progress)
System.Console.Error.WriteLine(" Checking for non-reduced productions...");
action_table.check_reductions();
reduce_check_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* if we have more conflicts than we expected issue a message and die */
if (emit.num_conflicts > expect_conflicts)
{
System.Console.Error.WriteLine("*** More conflicts encountered than expected " + "-- parser generation aborted");
lexer.error_count++; // indicate the problem.
// we'll die on return, after clean up.
}
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Produce a (semi-) human readable dump of the complete viable prefix
/// recognition state machine.
/// </summary>
public static void dump_machine()
{
lalr_state[] ordered = new lalr_state[lalr_state.number()];
/* put the states in sorted order for a nicer display */
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (System.Collections.IEnumerator s = lalr_state.all(); s.MoveNext(); )
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
lalr_state st = (lalr_state) s.Current;
ordered[st.index()] = st;
}
System.Console.Error.WriteLine("===== Viable Prefix Recognizer =====");
for (int i = 0; i < lalr_state.number(); i++)
{
if (ordered[i] == start_state)
System.Console.Error.Write("START ");
System.Console.Error.WriteLine(ordered[i]);
System.Console.Error.WriteLine("-------------------");
}
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Constructor with null next.
/// </summary>
/// <param name="on_sym"> symbol we are transitioning on.
/// </param>
/// <param name="to_st"> state we transition to.
///
/// </param>
public lalr_transition(symbol on_sym, lalr_state to_st)
: this(on_sym, to_st, null)
{
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>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>
/// </summary>
protected internal static void build_parser()
{
/* compute nullability of all non terminals */
if (opt_do_debug || print_progress)
{
System.Console.Error.WriteLine(" Computing non-terminal nullability...");
}
non_terminal.compute_nullability();
nullability_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* compute first sets of all non terminals */
if (opt_do_debug || print_progress)
{
System.Console.Error.WriteLine(" Computing first sets...");
}
non_terminal.compute_first_sets();
first_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* build the LR viable prefix recognition machine */
if (opt_do_debug || print_progress)
{
System.Console.Error.WriteLine(" Building state machine...");
}
start_state = lalr_state.build_machine(emit.start_production);
machine_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* build the LR parser action and reduce-goto tables */
if (opt_do_debug || print_progress)
{
System.Console.Error.WriteLine(" Filling in tables...");
}
action_table = new parse_action_table();
reduce_table = new parse_reduce_table();
for (System.Collections.IEnumerator st = lalr_state.all(); st.MoveNext();)
{
lalr_state lst = (lalr_state)st.Current;
lst.build_table_entries(action_table, reduce_table);
}
table_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* check and warn for non-reduced productions */
if (opt_do_debug || print_progress)
{
System.Console.Error.WriteLine(" Checking for non-reduced productions...");
}
action_table.check_reductions();
reduce_check_end = (System.DateTime.Now.Ticks - 621355968000000000) / 10000;
/* if we have more conflicts than we expected issue a message and die */
if (emit.num_conflicts > expect_conflicts)
{
System.Console.Error.WriteLine("*** More conflicts encountered than expected " + "-- parser generation aborted");
lexer.error_count++; // indicate the problem.
// we'll die on return, after clean up.
}
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Equality comparison.
/// </summary>
public virtual bool equals(lalr_state other)
{
/* we are equal if our item sets are equal */
return(other != null && items().equals(other.items()));
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Build an LALR viable prefix recognition machine given a start
/// production. This method operates by first building a start state
/// from the start production (based on a single item with the dot at
/// the beginning and EOF as expected lookahead). Then for each state
/// it attempts to extend the machine by creating transitions out of
/// the state to new or existing states. When considering extension
/// from a state we make a transition on each symbol that appears before
/// the dot in some item. For example, if we have the items: <pre>
/// [A ::= a b * X c, {d,e}]
/// [B ::= a b * X d, {a,b}]
/// </pre>
/// in some state, then we would be making a transition under X to a new
/// state. This new state would be formed by a "kernel" of items
/// corresponding to moving the dot past the X. In this case: <pre>
/// [A ::= a b X * c, {d,e}]
/// [B ::= a b X * Y, {a,b}]
/// </pre>
/// The full state would then be formed by "closing" this kernel set of
/// items so that it included items that represented productions of things
/// the parser was now looking for. In this case we would items
/// corresponding to productions of Y, since various forms of Y are expected
/// next when in this state (see lalr_item_set.compute_closure() for details
/// on closure). <p>
/// *
/// The process of building the viable prefix recognizer terminates when no
/// new states can be added. However, in order to build a smaller number of
/// states (i.e., corresponding to LALR rather than canonical LR) the state
/// building process does not maintain full loookaheads in all items.
/// Consequently, after the machine is built, we go back and propagate
/// lookaheads through the constructed machine using a call to
/// propagate_all_lookaheads(). This makes use of propagation links
/// constructed during the closure and transition process.
/// *
/// </summary>
/// <param name="start_prod">the start production of the grammar
/// </param>
/// <seealso cref=" CUP.lalr_item_set#compute_closure
/// "/>
/// <seealso cref=" CUP.lalr_state#propagate_all_lookaheads
///
/// "/>
public static lalr_state build_machine(production start_prod)
{
lalr_state start_state;
lalr_item_set start_items;
lalr_item_set new_items;
lalr_item_set linked_items;
lalr_item_set kernel;
CUP.runtime.SymbolStack work_stack = new CUP.runtime.SymbolStack();
lalr_state st, new_st;
symbol_set outgoing;
lalr_item itm, new_itm, existing, fix_itm;
symbol sym, sym2;
System.Collections.IEnumerator i, s, fix;
/* sanity check */
if (start_prod == null)
{
throw new internal_error("Attempt to build viable prefix recognizer using a null production");
}
/* build item with dot at front of start production and EOF lookahead */
start_items = new lalr_item_set();
itm = new lalr_item(start_prod);
itm.lookahead().add(terminal.EOF);
start_items.add(itm);
/* create copy the item set to form the kernel */
kernel = new lalr_item_set(start_items);
/* create the closure from that item set */
start_items.compute_closure();
/* build a state out of that item set and put it in our work set */
start_state = new lalr_state(start_items);
System.Object temp_object;
temp_object = start_state;
System.Object generatedAux = temp_object;
work_stack.Push(temp_object);
/* enter the state using the kernel as the key */
SupportClass.PutElement(_all_kernels, kernel, start_state);
/* continue looking at new states until we have no more work to do */
while (!(work_stack.Count == 0))
{
/* remove a state from the work set */
st = (lalr_state)work_stack.Pop();
/* gather up all the symbols that appear before dots */
outgoing = new symbol_set();
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (i = st.items().all(); i.MoveNext();)
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
itm = (lalr_item)i.Current;
/* add the symbol before the dot (if any) to our collection */
sym = itm.symbol_after_dot();
if (sym != null)
{
outgoing.add(sym);
}
}
/* now create a transition out for each individual symbol */
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (s = outgoing.all(); s.MoveNext();)
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
sym = (symbol)s.Current;
/* will be keeping the set of items with propagate links */
linked_items = new lalr_item_set();
/* gather up shifted versions of all the items that have this
* symbol before the dot */
new_items = new lalr_item_set();
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (i = st.items().all(); i.MoveNext();)
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
itm = (lalr_item)i.Current;
/* if this is the symbol we are working on now, add to set */
sym2 = itm.symbol_after_dot();
if (sym.Equals(sym2))
{
/* add to the kernel of the new state */
new_items.add(itm.shift());
/* remember that itm has propagate link to it */
linked_items.add(itm);
}
}
/* use new items as state kernel */
kernel = new lalr_item_set(new_items);
/* have we seen this one already? */
new_st = (lalr_state)_all_kernels[kernel];
/* if we haven't, build a new state out of the item set */
if (new_st == null)
{
/* compute closure of the kernel for the full item set */
new_items.compute_closure();
/* build the new state */
new_st = new lalr_state(new_items);
/* add the new state to our work set */
System.Object temp_object2;
temp_object2 = new_st;
System.Object generatedAux2 = temp_object2;
work_stack.Push(temp_object2);
/* put it in our kernel table */
SupportClass.PutElement(_all_kernels, kernel, new_st);
}
else
{
/* walk through the items that have links to the new state */
//UPGRADE_TODO: method 'java.util.Enumeration.hasMoreElements' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationhasMoreElements"'
for (fix = linked_items.all(); fix.MoveNext();)
{
//UPGRADE_TODO: method 'java.util.Enumeration.nextElement' was converted to ' ' which has a different behavior. 'ms-help://MS.VSCC/commoner/redir/redirect.htm?keyword="jlca1073_javautilEnumerationnextElement"'
fix_itm = (lalr_item)fix.Current;
/* look at each propagate link out of that item */
for (int l = 0; l < fix_itm.propagate_items().Count; l++)
{
/* pull out item linked to in the new state */
new_itm = (lalr_item)(fix_itm.propagate_items().Peek(fix_itm.propagate_items().Count - (l + 1)));
/* find corresponding item in the existing state */
existing = new_st.items().find(new_itm);
/* fix up the item so it points to the existing set */
if (existing != null)
{
fix_itm.propagate_items()[l] = existing;
}
}
}
}
/* add a transition from current state to that state */
st.add_transition(sym, new_st);
}
}
/* all done building states */
/* propagate complete lookahead sets throughout the states */
propagate_all_lookaheads();
return(start_state);
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Constructor with null next.
/// </summary>
/// <param name="on_sym"> symbol we are transitioning on.
/// </param>
/// <param name="to_st"> state we transition to.
///
/// </param>
public lalr_transition(symbol on_sym, lalr_state to_st) : this(on_sym, to_st, null)
{
}
