/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Equality comparison.
/// </summary>
public virtual bool equals(lalr_item_set other)
{
if (other == null || other.size() != size())
{
return(false);
}
/* once we know they are the same size, then improper subset does test */
try
{
return(is_subset_of(other));
}
catch (internal_error e)
{
/* can't throw error from here (because superclass doesn't) so crash */
e.crash();
return(false);
}
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Equality comparison.
/// </summary>
public virtual bool equals(lalr_item_set other)
{
if (other == null || other.size() != size())
return false;
/* once we know they are the same size, then improper subset does test */
try
{
return is_subset_of(other);
}
catch (internal_error e)
{
/* can't throw error from here (because superclass doesn't) so crash */
e.crash();
return false;
}
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Compute the closure of the set using the LALR closure rules. Basically
/// for every item of the form: <pre>
/// [L ::= a *N alpha, l]
/// </pre>
/// (where N is a a non terminal and alpha is a string of symbols) make
/// sure there are also items of the form: <pre>
/// [N ::= *beta, first(alpha l)]
/// </pre>
/// corresponding to each production of N. Items with identical cores but
/// differing lookahead sets are merged by creating a new item with the same
/// core and the union of the lookahead sets (the LA in LALR stands for
/// "lookahead merged" and this is where the merger is). This routine
/// assumes that nullability and first sets have been computed for all
/// productions before it is called.
/// </summary>
public virtual void compute_closure()
{
lalr_item_set consider;
lalr_item itm, new_itm, add_itm;
non_terminal nt;
terminal_set new_lookaheads;
System.Collections.IEnumerator p;
production prod;
bool need_prop;
/* invalidate cached hashcode */
hashcode_cache = int.MinValue;
/* each current element needs to be considered */
consider = new lalr_item_set(this);
/* repeat this until there is nothing else to consider */
while (consider.size() > 0)
{
/* get one item to consider */
itm = consider.get_one();
/* do we have a dot before a non terminal */
nt = itm.dot_before_nt();
if (nt != null)
{
/* create the lookahead set based on first after dot */
new_lookaheads = itm.calc_lookahead(itm.lookahead());
/* are we going to need to propagate our lookahead to new item */
need_prop = itm.lookahead_visible();
/* create items for each production of that non term */
//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 (p = nt.productions(); p.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"'
prod = (production) p.Current;
/* create new item with dot at start and that lookahead */
new_itm = new lalr_item(prod, new terminal_set(new_lookaheads));
/* add/merge item into the set */
add_itm = add(new_itm);
/* if propagation is needed link to that item */
if (need_prop)
itm.add_propagate(add_itm);
/* was this was a new item*/
if (add_itm == new_itm)
{
/* that may need further closure, consider it also */
consider.add(new_itm);
}
}
}
}
}
/*. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .*/
/// <summary>Compute the closure of the set using the LALR closure rules. Basically
/// for every item of the form: <pre>
/// [L ::= a *N alpha, l]
/// </pre>
/// (where N is a a non terminal and alpha is a string of symbols) make
/// sure there are also items of the form: <pre>
/// [N ::= *beta, first(alpha l)]
/// </pre>
/// corresponding to each production of N. Items with identical cores but
/// differing lookahead sets are merged by creating a new item with the same
/// core and the union of the lookahead sets (the LA in LALR stands for
/// "lookahead merged" and this is where the merger is). This routine
/// assumes that nullability and first sets have been computed for all
/// productions before it is called.
/// </summary>
public virtual void compute_closure()
{
lalr_item_set consider;
lalr_item itm, new_itm, add_itm;
non_terminal nt;
terminal_set new_lookaheads;
System.Collections.IEnumerator p;
production prod;
bool need_prop;
/* invalidate cached hashcode */
hashcode_cache = int.MinValue;
/* each current element needs to be considered */
consider = new lalr_item_set(this);
/* repeat this until there is nothing else to consider */
while (consider.size() > 0)
{
/* get one item to consider */
itm = consider.get_one();
/* do we have a dot before a non terminal */
nt = itm.dot_before_nt();
if (nt != null)
{
/* create the lookahead set based on first after dot */
new_lookaheads = itm.calc_lookahead(itm.lookahead());
/* are we going to need to propagate our lookahead to new item */
need_prop = itm.lookahead_visible();
/* create items for each production of that non term */
//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 (p = nt.productions(); p.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"'
prod = (production)p.Current;
/* create new item with dot at start and that lookahead */
new_itm = new lalr_item(prod, new terminal_set(new_lookaheads));
/* add/merge item into the set */
add_itm = add(new_itm);
/* if propagation is needed link to that item */
if (need_prop)
{
itm.add_propagate(add_itm);
}
/* was this was a new item*/
if (add_itm == new_itm)
{
/* that may need further closure, consider it also */
consider.add(new_itm);
}
}
}
}
}