/* AW: this replaces the method int Alternatives (Node p) */
static bool UseSwitch (Node p) {
if (p.typ != Node.alt) return false;
int nAlts = 0;
while (p != null) {
++nAlts;
// must not optimize with switch-statement, if alt uses a resolver expression
if (p.sub.typ == Node.rslv) return false;
p = p.down;
}
return nAlts > 5;
}
// use a switch if more than 5 alternatives and none starts with a resolver
bool UseSwitch (Node p) {
BitArray s1, s2;
if (p.typ != Node.alt) return false;
int nAlts = 0;
s1 = new BitArray(tab.terminals.Count);
while (p != null) {
s2 = tab.Expected0(p.sub, curSy);
// must not optimize with switch statement, if there are ll1 warnings
if (Overlaps(s1, s2)) { return false; }
s1.Or(s2);
++nAlts;
// must not optimize with switch-statement, if alt uses a resolver expression
if (p.sub.typ == Node.rslv) return false;
p = p.down;
}
return nAlts > 5;
}
void GenCode(Node p, int indent, BitArray isChecked)
{
Node p2;
BitArray s1, s2;
while (p != null) {
switch (p.typ) {
case Node.nt: {
Indent(indent);
gen.Write(p.sym.name + "(");
CopySourcePart(p.pos, 0);
gen.WriteLine(");");
break;
}
case Node.t: {
Indent(indent);
// assert: if isChecked[p.sym.n] is true, then isChecked contains only p.sym.n
if (isChecked[p.sym.n]) gen.WriteLine("Get();");
else gen.WriteLine("Expect({0});", p.sym.n);
break;
}
case Node.wt: {
Indent(indent);
s1 = tab.Expected(p.next, curSy);
s1.Or(tab.allSyncSets);
gen.WriteLine("ExpectWeak({0}, {1});", p.sym.n, NewCondSet(s1));
break;
}
case Node.any: {
Indent(indent);
int acc = Sets.Elements(p.set);
if (tab.terminals.Count == (acc + 1) || (acc > 0 && Sets.Equals(p.set, isChecked))) {
// either this ANY accepts any terminal (the + 1 = end of file), or exactly what's allowed here
gen.WriteLine("Get();");
} else {
GenErrorMsg(altErr, curSy);
if (acc > 0) {
gen.Write("if ("); GenCond(p.set, p); gen.WriteLine(") Get(); else SynErr({0});", errorNr);
} else gen.WriteLine("SynErr({0}); // ANY node that matches no symbol", errorNr);
}
break;
}
case Node.eps: break; // nothing
case Node.rslv: break; // nothing
case Node.sem: {
CopySourcePart(p.pos, indent);
break;
}
case Node.sync: {
Indent(indent);
GenErrorMsg(syncErr, curSy);
s1 = (BitArray)p.set.Clone();
gen.Write("while (!("); GenCond(s1, p); gen.Write(")) {");
gen.Write("SynErr({0}); Get();", errorNr); gen.WriteLine("}");
break;
}
case Node.alt: {
s1 = tab.First(p);
bool equal = Sets.Equals(s1, isChecked);
bool useSwitch = UseSwitch(p);
if (useSwitch) { Indent(indent); gen.WriteLine("switch (la.kind) {"); }
p2 = p;
while (p2 != null) {
s1 = tab.Expected(p2.sub, curSy);
Indent(indent);
if (useSwitch) {
PutCaseLabels(s1); gen.WriteLine("{");
} else if (p2 == p) {
gen.Write("if ("); GenCond(s1, p2.sub); gen.WriteLine(") {");
} else if (p2.down == null && equal) { gen.WriteLine("} else {");
} else {
gen.Write("} else if ("); GenCond(s1, p2.sub); gen.WriteLine(") {");
}
GenCode(p2.sub, indent + 1, s1);
if (useSwitch) {
Indent(indent); gen.WriteLine("\tbreak;");
Indent(indent); gen.WriteLine("}");
}
p2 = p2.down;
}
Indent(indent);
if (equal) {
gen.WriteLine("}");
} else {
GenErrorMsg(altErr, curSy);
if (useSwitch) {
gen.WriteLine("default: SynErr({0}); break;", errorNr);
Indent(indent); gen.WriteLine("}");
} else {
gen.Write("} "); gen.WriteLine("else SynErr({0});", errorNr);
}
}
break;
}
case Node.iter: {
Indent(indent);
p2 = p.sub;
gen.Write("while (");
if (p2.typ == Node.wt) {
s1 = tab.Expected(p2.next, curSy);
s2 = tab.Expected(p.next, curSy);
gen.Write("WeakSeparator({0},{1},{2}) ", p2.sym.n, NewCondSet(s1), NewCondSet(s2));
s1 = new BitArray(tab.terminals.Count); // for inner structure
if (p2.up || p2.next == null) p2 = null; else p2 = p2.next;
} else {
s1 = tab.First(p2);
GenCond(s1, p2);
}
gen.WriteLine(") {");
GenCode(p2, indent + 1, s1);
Indent(indent); gen.WriteLine("}");
break;
}
case Node.opt:
s1 = tab.First(p.sub);
Indent(indent);
gen.Write("if ("); GenCond(s1, p.sub); gen.WriteLine(") {");
GenCode(p.sub, indent + 1, s1);
Indent(indent); gen.WriteLine("}");
break;
}
if (p.typ != Node.eps && p.typ != Node.sem && p.typ != Node.sync)
isChecked.SetAll(false); // = new BitArray(tab.terminals.Count);
if (p.up) break;
p = p.next;
}
}
State TheState(Node p)
{
State state;
if (p == null) {state = NewState(); state.endOf = curSy; return state;}
else return p.state;
}
// Assigns a state n.state to every node n. There will be a transition from
// n.state to n.next.state triggered by n.val. All nodes in an alternative
// chain are represented by the same state.
// Numbering scheme:
// - any node after a chr, clas, opt, or alt, must get a new number
// - if a nested structure starts with an iteration the iter node must get a new number
// - if an iteration follows an iteration, it must get a new number
void NumberNodes(Node p, State state, bool renumIter)
{
if (p == null) return;
if (p.state != null) return; // already visited;
if (state == null || (p.typ == Node.iter && renumIter)) state = NewState();
p.state = state;
if (Tab.DelGraph(p)) state.endOf = curSy;
switch (p.typ) {
case Node.clas: case Node.chr: {
NumberNodes(p.next, null, false);
break;
}
case Node.opt: {
NumberNodes(p.next, null, false);
NumberNodes(p.sub, state, true);
break;
}
case Node.iter: {
NumberNodes(p.next, state, true);
NumberNodes(p.sub, state, true);
break;
}
case Node.alt: {
NumberNodes(p.next, null, false);
NumberNodes(p.sub, state, true);
NumberNodes(p.down, state, renumIter);
break;
}
}
}
string CommentStr(Node p)
{
StringBuilder s = new StringBuilder();
while (p != null) {
if (p.typ == Node.chr) {
s.Append((char)p.val);
} else if (p.typ == Node.clas) {
CharSet set = tab.CharClassSet(p.val);
if (set.Elements() != 1) parser.SemErr("character set contains more than 1 character");
s.Append((char)set.First());
} else parser.SemErr("comment delimiters may not be structured");
p = p.next;
}
if (s.Length == 0 || s.Length > 2) {
parser.SemErr("comment delimiters must be 1 or 2 characters long");
s = new StringBuilder("?");
}
return s.ToString();
}
public void ConvertToStates(Node p, Symbol sym)
{
curSy = sym;
if (Tab.DelGraph(p)) {
parser.SemErr("token might be empty");
return;
}
NumberNodes(p, firstState, true);
FindTrans(p, true, new BitArray(tab.nodes.Count));
if (p.typ == Node.iter) {
Step(firstState, p, new BitArray(tab.nodes.Count));
}
}
void GetSingles(Node p, ArrayList singles) {
if (p == null) return; // end of graph
if (p.typ == Node.nt) {
if (p.up || DelGraph(p.next)) singles.Add(p.sym);
} else if (p.typ == Node.alt || p.typ == Node.iter || p.typ == Node.opt) {
if (p.up || DelGraph(p.next)) {
GetSingles(p.sub, singles);
if (p.typ == Node.alt) GetSingles(p.down, singles);
}
}
if (!p.up && DelNode(p)) GetSingles(p.next, singles);
}
public static bool DelNode(Node p) {
if (p.typ == Node.nt) return p.sym.deletable;
else if (p.typ == Node.alt) return DelSubGraph(p.sub) || p.down != null && DelSubGraph(p.down);
else return p.typ == Node.iter || p.typ == Node.opt || p.typ == Node.sem
|| p.typ == Node.eps || p.typ == Node.rslv || p.typ == Node.sync;
}
public static bool DelSubGraph(Node p) {
return p == null || DelNode(p) && (p.up || DelSubGraph(p.next));
}
//------------ graph deletability check -----------------
public static bool DelGraph(Node p) {
return p == null || DelNode(p) && DelGraph(p.next);
}
public void SetContextTrans(Node p) { // set transition code in the graph rooted at p
while (p != null) {
if (p.typ == Node.chr || p.typ == Node.clas) {
p.code = Node.contextTrans;
} else if (p.typ == Node.opt || p.typ == Node.iter) {
SetContextTrans(p.sub);
} else if (p.typ == Node.alt) {
SetContextTrans(p.sub); SetContextTrans(p.down);
}
if (p.up) break;
p = p.next;
}
}
public void DeleteNodes() {
nodes = new ArrayList();
dummyNode = NewNode(Node.eps, null, 0);
}
public Node NewNode(int typ, Node sub) {
Node node = NewNode(typ, null, 0);
node.sub = sub;
return node;
}
public Node NewNode(int typ, Symbol sym, int line) {
Node node = new Node(typ, sym, line);
node.n = nodes.Count;
nodes.Add(node);
return node;
}
// does not look behind resolvers; only called during LL(1) test and in CheckRes
public BitArray Expected0(Node p, Symbol curSy) {
if (p.typ == Node.rslv) return new BitArray(terminals.Count);
else return Expected(p, curSy);
}
void CompSync(Node p) {
while (p != null && !visited[p.n]) {
visited[p.n] = true;
if (p.typ == Node.sync) {
BitArray s = Expected(p.next, curSy);
s[eofSy.n] = true;
allSyncSets.Or(s);
p.set = s;
} else if (p.typ == Node.alt) {
CompSync(p.sub); CompSync(p.down);
} else if (p.typ == Node.opt || p.typ == Node.iter)
CompSync(p.sub);
p = p.next;
}
}
//----------------- graph printing ----------------------
string Ptr(Node p, bool up) {
string ptr = (p == null) ? "0" : p.n.ToString();
return (up) ? ("-" + ptr) : ptr;
}
void CheckAlts(Node p) {
BitArray s1, s2;
while (p != null) {
if (p.typ == Node.alt) {
Node q = p;
s1 = new BitArray(terminals.Count);
while (q != null) { // for all alternatives
s2 = Expected0(q.sub, curSy);
CheckOverlap(s1, s2, 1);
s1.Or(s2);
CheckAlts(q.sub);
q = q.down;
}
} else if (p.typ == Node.opt || p.typ == Node.iter) {
if (DelSubGraph(p.sub)) LL1Error(4, null); // e.g. [[...]]
else {
s1 = Expected0(p.sub, curSy);
s2 = Expected(p.next, curSy);
CheckOverlap(s1, s2, 2);
}
CheckAlts(p.sub);
} else if (p.typ == Node.any) {
if (Sets.Elements(p.set) == 0) LL1Error(3, null);
// e.g. {ANY} ANY or [ANY] ANY or ( ANY | ANY )
}
if (p.up) break;
p = p.next;
}
}
//---------------------------------------------------------------------
// Symbol set computations
//---------------------------------------------------------------------
/* Computes the first set for the graph rooted at p */
BitArray First0(Node p, BitArray mark) {
BitArray fs = new BitArray(terminals.Count);
while (p != null && !mark[p.n]) {
mark[p.n] = true;
switch (p.typ) {
case Node.nt: {
if (p.sym.firstReady) fs.Or(p.sym.first);
else fs.Or(First0(p.sym.graph, mark));
break;
}
case Node.t: case Node.wt: {
fs[p.sym.n] = true; break;
}
case Node.any: {
fs.Or(p.set); break;
}
case Node.alt: {
fs.Or(First0(p.sub, mark));
fs.Or(First0(p.down, mark));
break;
}
case Node.iter: case Node.opt: {
fs.Or(First0(p.sub, mark));
break;
}
}
if (!DelNode(p)) break;
p = p.next;
}
return fs;
}
public void NewComment(Node from, Node to, bool nested)
{
Comment c = new Comment(CommentStr(from), CommentStr(to), nested);
c.next = firstComment; firstComment = c;
}
public BitArray First(Node p) {
BitArray fs = First0(p, new BitArray(nodes.Count));
if (ddt[3]) {
trace.WriteLine();
if (p != null) trace.WriteLine("First: node = {0}", p.n);
else trace.WriteLine("First: node = null");
PrintSet(fs, 0);
}
return fs;
}
void FindTrans(Node p, bool start, BitArray marked)
{
if (p == null || marked[p.n]) return;
marked[p.n] = true;
if (start) Step(p.state, p, new BitArray(tab.nodes.Count)); // start of group of equally numbered nodes
switch (p.typ) {
case Node.clas: case Node.chr: {
FindTrans(p.next, true, marked);
break;
}
case Node.opt: {
FindTrans(p.next, true, marked); FindTrans(p.sub, false, marked);
break;
}
case Node.iter: {
FindTrans(p.next, false, marked); FindTrans(p.sub, false, marked);
break;
}
case Node.alt: {
FindTrans(p.sub, false, marked); FindTrans(p.down, false, marked);
break;
}
}
}
void CompFollow(Node p) {
while (p != null && !visited[p.n]) {
visited[p.n] = true;
if (p.typ == Node.nt) {
BitArray s = First(p.next);
p.sym.follow.Or(s);
if (DelGraph(p.next))
p.sym.nts[curSy.n] = true;
} else if (p.typ == Node.opt || p.typ == Node.iter) {
CompFollow(p.sub);
} else if (p.typ == Node.alt) {
CompFollow(p.sub); CompFollow(p.down);
}
p = p.next;
}
}
void Step(State from, Node p, BitArray stepped)
{
if (p == null) return;
stepped[p.n] = true;
switch (p.typ) {
case Node.clas: case Node.chr: {
NewTransition(from, TheState(p.next), p.typ, p.val, p.code);
break;
}
case Node.alt: {
Step(from, p.sub, stepped); Step(from, p.down, stepped);
break;
}
case Node.iter: {
if (Tab.DelSubGraph(p.sub)) {
parser.SemErr("contents of {...} must not be deletable");
return;
}
if (p.next != null && !stepped[p.next.n]) Step(from, p.next, stepped);
Step(from, p.sub, stepped);
if (p.state != from) {
Step(p.state, p, new BitArray(tab.nodes.Count));
}
break;
}
case Node.opt: {
if (p.next != null && !stepped[p.next.n]) Step(from, p.next, stepped);
Step(from, p.sub, stepped);
break;
}
}
}
Node LeadingAny(Node p) {
if (p == null) return null;
Node a = null;
if (p.typ == Node.any) a = p;
else if (p.typ == Node.alt) {
a = LeadingAny(p.sub);
if (a == null) a = LeadingAny(p.down);
}
else if (p.typ == Node.opt || p.typ == Node.iter) a = LeadingAny(p.sub);
if (a == null && DelNode(p) && !p.up) a = LeadingAny(p.next);
return a;
}
void Attribs(Node p)
{
if (la.kind == 30) {
Get();
int beg = la.pos; int col = la.col; int line = la.line;
while (StartOf(11)) {
if (StartOf(12)) {
Get();
} else {
Get();
SemErr("bad string in attributes");
}
}
Expect(31);
if (t.pos > beg) p.pos = new Position(beg, t.pos, col, line);
} else if (la.kind == 32) {
Get();
int beg = la.pos; int col = la.col; int line = la.line;
while (StartOf(13)) {
if (StartOf(14)) {
Get();
} else {
Get();
SemErr("bad string in attributes");
}
}
Expect(33);
if (t.pos > beg) p.pos = new Position(beg, t.pos, col, line);
} else SynErr(60);
}
void FindAS(Node p) { // find ANY sets
Node a;
while (p != null) {
if (p.typ == Node.opt || p.typ == Node.iter) {
FindAS(p.sub);
a = LeadingAny(p.sub);
if (a != null) Sets.Subtract(a.set, First(p.next));
} else if (p.typ == Node.alt) {
BitArray s1 = new BitArray(terminals.Count);
Node q = p;
while (q != null) {
FindAS(q.sub);
a = LeadingAny(q.sub);
if (a != null)
Sets.Subtract(a.set, First(q.down).Or(s1));
else
s1.Or(First(q.sub));
q = q.down;
}
}
// Remove alternative terminals before ANY, in the following
// examples a and b must be removed from the ANY set:
// [a] ANY, or {a|b} ANY, or [a][b] ANY, or (a|) ANY, or
// A = [a]. A ANY
if (DelNode(p)) {
a = LeadingAny(p.next);
if (a != null) {
Node q = (p.typ == Node.nt) ? p.sym.graph : p.sub;
Sets.Subtract(a.set, First(q));
}
}
if (p.up) break;
p = p.next;
}
}
void GenCond(BitArray s, Node p)
{
if (p.typ == Node.rslv) CopySourcePart(p.pos, 0);
else {
int n = Sets.Elements(s);
if (n == 0) gen.Write("false"); // happens if an ANY set matches no symbol
else if (n <= maxTerm)
foreach (Symbol sym in tab.terminals) {
if (s[sym.n]) {
gen.Write("la.kind == {0}", sym.n);
--n;
if (n > 0) gen.Write(" || ");
}
}
else
gen.Write("StartOf({0})", NewCondSet(s));
}
}
public BitArray Expected(Node p, Symbol curSy) {
BitArray s = First(p);
if (DelGraph(p)) s.Or(curSy.follow);
return s;
}
