automata stuff for pattern matching

1 files changed, 120 insertions, 0 deletions

diff --git a/sources/scalac/transformer/matching/Label.java b/sources/scalac/transformer/matching/Label.java
new file mode 100644
index 0000000000..389139da0a
--- /dev/null
+++ b/sources/scalac/transformer/matching/Label.java
@@ -0,0 +1,120 @@
+package scalac.transformer.matching ;
+
+import scalac.ast.Tree ;
+import scalac.symtab.Type ;
+import Tree.Literal ;
+
+/** this class represents the label that a transition in an automaton may carry.
+ *  these get translated to specific (boolean) tests
+ */
+
+public class Label {
+
+
+      public case DefaultLabel;
+      public case SimpleLabel( Literal lit );
+      public case TreeLabel( Tree pat ); // Apply, Sequence
+
+      public case TypeLabel( Type tpe ); // Apply, Sequence
+
+      public case Pair( Integer state, Label lab );
+
+      //public case RLabel( Object rstate, Label lab, Symbol vars[] );
+
+      public int hashCode() {
+            switch( this ) {
+            case DefaultLabel:
+                  return 0;
+            case SimpleLabel( Literal lit ):
+                  return lit.value.hashCode();
+            case TreeLabel( Tree pat ):
+                  return pat.hashCode();
+            case TypeLabel( Type type ):
+                  return type.hashCode();
+            default:
+                  return super.hashCode();
+            }
+      }
+
+      public boolean equals( Object o ) {
+            if( !(o instanceof Label ))
+                  return false;
+            Label oL = (Label) o;
+            //System.out.print(this + " equals " + oL);
+            switch( this ) {
+            case DefaultLabel:
+                  switch( oL ) {
+                  case DefaultLabel:
+                        return true;
+                  } //
+                  break;
+            case SimpleLabel( Literal lit ):
+                  switch( oL ) {
+                  case SimpleLabel( Literal lit2 ):
+                        return /*(lit.kind == lit2.kind)
+				 && */lit.value.equals( lit2.value );
+                  }
+                  break;
+            case TreeLabel( Tree pat ):
+                  switch( oL ) {
+                  case TreeLabel( Tree pat2):
+                        return pat == pat2;
+                  }
+                  break ;
+            case TypeLabel( Type tpe ):
+                  switch( oL ) {
+                  case TypeLabel( Type tpe2):
+                        return tpe.equals( tpe2 );
+                  }
+                  break ;
+            case Pair( Integer state, Label lab ):
+                  switch( oL ) {
+                  case Pair(  Integer state2, Label lab2 ):
+                        return  state.equals( state2 )
+                                 && lab.equals( lab2 ) ;
+                  }
+                  break;
+            }
+            return false;
+      }
+
+
+      public String toString2() {
+            String ext = System.getProperty("extendedMatching");
+            if(( ext != null )
+               && ext.equals( "true" )) {
+                  switch( this ) {
+                  case DefaultLabel:
+                        return "<>:p"+p;
+                  case SimpleLabel( Literal lit ):
+                        return lit.toString()+":p"+p;
+                  case TreeLabel( Tree pat ):
+                        return pat.type()+":p"+p;
+
+                  }
+            }
+            throw new scalac.ApplicationError
+                  ("this never happens");
+      }
+
+      public String toString() {
+
+            switch( this ) {
+            case DefaultLabel:
+                  return "<>";
+            case SimpleLabel( Literal lit):
+                  return lit.toString();
+            case TreeLabel( Tree pat):
+                  return pat.toString();
+            case TypeLabel( Type tpe ):
+                  return tpe.toString();
+            case Pair( Integer state, Label lab  ):
+                  return "("+state.toString()+","+lab.toString()+")";
+            }
+            throw new scalac.ApplicationError("this never happens");
+      }
+
+      int p = -1; // tree state - only needed for extended matching
+
+
+}