Simplify handling of alternation metadata

lib/CLRBackend.cs

@@ -3246,8 +3246,6 @@ class NamProcessor {
                     } else {
                         Console.WriteLine("odd constant box {0}/{1}", typ, chchh);
                     }
-                } else if (chh == "label_table" || chh == "ladconstruct") {
-                    // probably not worth trying to coalesce
                 } else if (chh == "newcc") {
                     StringBuilder sb = new StringBuilder("C");
                     for (int i = 1; i < ch.Length; i++) {
@@ -3423,8 +3421,14 @@ class NamProcessor {
                 return CpsOp.MethodCall(Tokens.RxFrame_PushBacktrack,
                     CpsOp.GetField(Tokens.Frame_rx, CpsOp.CallFrame()),
                     CpsOp.LabelId(th.cpb.cx, JScalar.S(z[2]))); };
-            handlers["label_table"] = delegate(NamProcessor th, object[] z) {
-                return CpsOp.LabelTable(th.cpb.cx, JScalar.SA(1,z)); };
+            handlers["ltm_push_alts"] = delegate(NamProcessor th, object[] z) {
+                CpsOp ai = CpsOp.ConstructorCall(typeof(AltInfo).GetConstructor(new Type[] { typeof(LAD[]), typeof(string), typeof(int[]) }),
+                        th.ProcessLADArr(z[1]),
+                        CpsOp.StringLiteral(JScalar.S(z[2])),
+                        CpsOp.LabelTable(th.cpb.cx, JScalar.SA(0,z[3])));
+                return CpsOp.MethodCall(Tokens.RxFrame.GetMethod("LTMPushAlts"),
+                    CpsOp.GetField(Tokens.Frame_rx, CpsOp.CallFrame()),
+                    CpsOp.CallFrame(), th.Constant(ai)); };
             thandlers["popcut"] = RxCall(null, "PopCutGroup");
             thandlers["rxend"] = RxCall(Tokens.Void, "End");
             thandlers["rxfinalend"] = RxCall(Tokens.Void, "FinalEnd");
@@ -3439,10 +3443,7 @@ class NamProcessor {
             thandlers["rxsetcapsfrom"] = RxCall(null, "SetCapturesFrom");
             thandlers["rxgetpos"] = RxCall(null, "GetPos");
             thandlers["rxcommitgroup"] = RxCall(null, "CommitGroup");
-            thandlers["get_lexer"] = Methody(null, typeof(Lexer).GetMethod("GetLexer"));
             thandlers["run_dispatch"] = Methody(null, typeof(Lexer).GetMethod("RunDispatch"));
-            handlers["ladconstruct"] = delegate(NamProcessor th, object[] z) {
-                return th.ProcessLADArr(z[1]); };
             handlers["rawcall"] = delegate(NamProcessor th, object[] z) {
                 string name = JScalar.S(z[1]);
                 CpsOp[] rst = JScalar.A<CpsOp>(2, z, th.Scan);

lib/Cursor.cs

@@ -119,6 +119,19 @@ public sealed class Choice {
     }
 }
 
+public class AltInfo {
+    public readonly int[] labels;
+    public readonly LAD[] prefixes;
+    public readonly string dba;
+    //public readonly STable in_class;
+
+    public AltInfo(LAD[] prefixes, string dba, int[] labels) {
+        this.labels = labels;
+        this.prefixes = prefixes;
+        this.dba = dba;
+    }
+}
+
 // extends Frame for a time/space tradeoff
 // we keep the cursor in exploded form to avoid creating lots and lots of
 // cursor objects
@@ -365,13 +378,14 @@ public sealed class RxFrame {
         return (i >= min);
     }
 
-    public void LTMPushAlts(Lexer lx, int[] addrs) {
+    public void LTMPushAlts(Frame fr, AltInfo ai) {
+        Lexer lx = Lexer.GetLexer(fr, GetClass(), ai.prefixes, ai.dba);
         if (st.pos > global.highwater)
             global.IncHighwater(st.pos);
         PushCutGroup("LTM");
         int[] cases = lx.Run(global.orig_s, st.pos);
         for (int i = cases.Length - 1; i >= 0; i--) {
-            PushBacktrack(addrs[cases[i]]);
+            PushBacktrack(ai.labels[cases[i]]);
         }
     }
 

src/niecza

@@ -48,6 +48,30 @@ method number($/) {
 }
 }
 
+augment class RxOp::Alt { #OK exist
+    method code($body) {
+        my @ls = map { self.label }, @$.zyg;
+        my @lads = @( $.optimized_lads // (map { $_.lad }, @$.zyg) );
+        my $end = self.label;
+
+        die "check screwed up" unless defined $.dba;
+
+        my @code;
+        push @code, CgOp.ltm_push_alts([@lads], $.dba, [@ls]);
+        push @code, CgOp.goto('backtrack');
+        my $i = 0;
+        while $i < @ls {
+            push @code, CgOp.label(@ls[$i]);
+            push @code, $.zyg[$i].code($body);
+            push @code, CgOp.goto($end) unless $i == @ls - 1;
+            $i++;
+        }
+        push @code, CgOp.label($end);
+        push @code, CgOp.popcut;
+        @code;
+    }
+}
+
 # XXX should there be a different class for this?
 augment class Op::Num { #OK exist
     method code($) {
@@ -71,6 +95,8 @@ class RxOp::CutBrack is RxOp {
 }
 
 augment class CgOp {
+# DELETE label_table, ladconstruct, get_lexer
+method ltm_push_alts (*@x) { self._cgop("ltm_push_alts", @x) }
 method outerlex ($n) { self._cgop("outerlex", $n) }
 method newtypedscalar ($t) { self._cgop("newtypedscalar", $t) }
 method bif_rand () { self._cgop("bif_rand") }