bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/elaboration/expressions/EAmbiguous.java

   1 package org.simantics.scl.compiler.elaboration.expressions;
   2
   3 import org.simantics.scl.compiler.common.exceptions.InternalCompilerError;
   4 import org.simantics.scl.compiler.elaboration.contexts.SimplificationContext;
   5 import org.simantics.scl.compiler.elaboration.contexts.TranslationContext;
   6 import org.simantics.scl.compiler.elaboration.contexts.TypingContext;
   7 import org.simantics.scl.compiler.errors.ErrorLog;
   8 import org.simantics.scl.compiler.errors.Locations;
   9 import org.simantics.scl.compiler.types.Skeletons;
  10 import org.simantics.scl.compiler.types.TMetaVar;
  11 import org.simantics.scl.compiler.types.Type;
  12 import org.simantics.scl.compiler.types.Types;
  13 import org.simantics.scl.compiler.types.exceptions.MatchException;
  14 import org.simantics.scl.compiler.types.exceptions.UnificationException;
  15 import org.simantics.scl.compiler.types.util.TypeListener;
  16 import org.simantics.scl.compiler.types.util.TypeUnparsingContext;
  17
  18 import gnu.trove.map.hash.THashMap;
  19 import gnu.trove.map.hash.TObjectIntHashMap;
  20 import gnu.trove.set.hash.TIntHashSet;
  21
  22 public class EAmbiguous extends SimplifiableExpression {
  23     public static final boolean DEBUG = false;
  24
  25     Alternative[] alternatives;
  26     boolean[] active;
  27     int activeCount;
  28     transient TypingContext context;
  29     public Expression resolvedExpression;
  30
  31     public abstract static class Alternative {
  32         public abstract Type getType();
  33         public abstract Expression realize();
  34     }
  35
  36     public EAmbiguous(Alternative[] alternatives) {
  37         this.alternatives = alternatives;
  38         this.active = new boolean[alternatives.length];
  39         for(int i=0;i<alternatives.length;++i)
  40             this.active[i] = true;
  41         this.activeCount = alternatives.length;
  42     }
  43
  44     @Override
  45     public void collectVars(TObjectIntHashMap<Variable> allVars,
  46             TIntHashSet vars) {
  47     }
  48
  49     @Override
  50     protected void updateType() throws MatchException {
  51         throw new InternalCompilerError();
  52     }
  53
  54     private Type getCommonSkeleton() {
  55         Type[] types = new Type[activeCount];
  56         for(int i=0,j=0;i<alternatives.length;++i)
  57             if(active[i])
  58                 types[j++] = Types.instantiateAndStrip(alternatives[i].getType());
  59         return Skeletons.commonSkeleton(context.getEnvironment(), types);
  60     }
  61
  62     private void filterActive() {
  63         THashMap<TMetaVar,Type> unifications = new THashMap<TMetaVar,Type>();
  64         Type requiredType = getType();
  65         if(DEBUG)
  66             System.out.println("EAmbigious.filterActive with " + requiredType);
  67         for(int i=0;i<alternatives.length;++i)
  68             if(active[i]) {
  69                 unifications.clear();
  70                 Type alternativeType = Types.instantiateAndStrip(alternatives[i].getType());
  71                 if(DEBUG)
  72                     System.out.println("    " + alternativeType);
  73                 if(!Skeletons.areSkeletonsCompatible(unifications, alternativeType, requiredType)) {
  74                     active[i] = false;
  75                     --activeCount;
  76                 }
  77             }
  78         if(DEBUG)
  79             System.out.println("    activeCount = " + activeCount);
  80     }
  81
  82     private String getNoMatchDescription(Type requiredType) {
  83         StringBuilder b = new StringBuilder();
  84         b.append("Expected <");
  85         requiredType.toString(new TypeUnparsingContext(), b);
  86         b.append(">, but no alteratives match the type: ");
  87         for(int i=0;i<alternatives.length;++i) {
  88             b.append("\n    ");
  89             b.append(alternatives[i]);
  90             b.append(" :: ");
  91             alternatives[i].getType().toString(new TypeUnparsingContext(), b);
  92         }
  93         b.append('.');
  94         return b.toString();
  95     }
  96
  97     private String getAmbiguousDescription(Type requiredType) {
  98         StringBuilder b = new StringBuilder();
  99         b.append("Expected <");
 100         requiredType.toString(new TypeUnparsingContext(), b);
 101         b.append(">, but multiple values match the type: ");
 102         for(int i=0;i<alternatives.length;++i) {
 103             b.append("\n    ");
 104             b.append(alternatives[i]);
 105             b.append(" :: ");
 106             alternatives[i].getType().toString(new TypeUnparsingContext(), b);
 107         }
 108         b.append('.');
 109         return b.toString();
 110     }
 111
 112
 113     private void resolveTo(int i) {
 114         if(DEBUG)
 115             System.out.println("EAmbigious.resolve to " + alternatives[i]);
 116         resolvedExpression = context.instantiate(alternatives[i].realize());
 117         Type requiredType = getType();
 118         try {
 119             Types.unify(resolvedExpression.getType(), requiredType);
 120         } catch (UnificationException e) {
 121             context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 122         }
 123     }
 124
 125     private void listenType() {
 126         if(DEBUG)
 127             System.out.println("EAmbigious.listenType " + getType());
 128         new TypeListener() {
 129             @Override
 130             public void notifyAboutChange() {
 131                 if(DEBUG)
 132                     System.out.println("EAmbigious.notifyAboutChange " + getType());
 133                 Type requiredType = getType();
 134                 filterActive();
 135                 if(activeCount == 0) {
 136                     context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 137                     return;
 138                 }
 139                 else if(activeCount == 1) {
 140                     for(int i=0;i<alternatives.length;++i)
 141                         if(active[i]) {
 142                             resolveTo(i);
 143                             return;
 144                         }
 145                 }
 146                 Type commonType = getCommonSkeleton();
 147                 try {
 148                     Skeletons.unifySkeletons(requiredType, commonType);
 149                     listenType();
 150                 } catch (UnificationException e) {
 151                     context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 152                 }
 153             }
 154         }.listenSkeleton(getType());
 155     }
 156
 157     @Override
 158     public Expression inferType(TypingContext context) {
 159         this.context = context;
 160         context.overloadedExpressions.add(this);
 161         setType(getCommonSkeleton());
 162         listenType();
 163         return this;
 164     }
 165
 166     @Override
 167     public Expression resolve(TranslationContext context) {
 168         throw new InternalCompilerError("EAmbiguousConstant should not exist in resolve phase.");
 169     }
 170
 171     @Override
 172     public void setLocationDeep(long loc) {
 173         if(location == Locations.NO_LOCATION)
 174             location = loc;
 175     }
 176
 177     @Override
 178     public void accept(ExpressionVisitor visitor) {
 179         visitor.visit(this);
 180     }
 181
 182     @Override
 183     public Expression simplify(SimplificationContext context) {
 184         if(resolvedExpression != null)
 185             return resolvedExpression;
 186         else {
 187             context.getErrorLog().log(location, getAmbiguousDescription(getType()));
 188             return this;
 189         }
 190     }
 191
 192     public void assertResolved(ErrorLog errorLog) {
 193         if(resolvedExpression == null)
 194             errorLog.log(location, getAmbiguousDescription(getType()));
 195     }
 196
 197     @Override
 198     public Expression accept(ExpressionTransformer transformer) {
 199         return transformer.transform(this);
 200     }
 201
 202 }