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.THashSet;
  21 import gnu.trove.set.hash.TIntHashSet;
  22
  23 public class EAmbiguous extends SimplifiableExpression {
  24     public static final boolean DEBUG = false;
  25
  26     Alternative[] alternatives;
  27     boolean[] active;
  28     int activeCount;
  29     transient TypingContext context;
  30     Expression resolvedExpression;
  31
  32     public abstract static class Alternative {
  33         public abstract Type getType();
  34         public abstract Expression realize();
  35     }
  36
  37     public EAmbiguous(Alternative[] alternatives) {
  38         this.alternatives = alternatives;
  39         this.active = new boolean[alternatives.length];
  40         for(int i=0;i<alternatives.length;++i)
  41             this.active[i] = true;
  42         this.activeCount = alternatives.length;
  43     }
  44
  45     @Override
  46     public void collectRefs(TObjectIntHashMap<Object> allRefs,
  47             TIntHashSet refs) {
  48     }
  49
  50     @Override
  51     public void collectVars(TObjectIntHashMap<Variable> allVars,
  52             TIntHashSet vars) {
  53     }
  54
  55     @Override
  56     protected void updateType() throws MatchException {
  57         throw new InternalCompilerError();
  58     }
  59
  60     private Type getCommonSkeleton() {
  61         Type[] types = new Type[activeCount];
  62         for(int i=0,j=0;i<alternatives.length;++i)
  63             if(active[i])
  64                 types[j++] = Types.instantiateAndStrip(alternatives[i].getType());
  65         return Skeletons.commonSkeleton(context.getEnvironment(), types);
  66     }
  67
  68     private void filterActive() {
  69         THashMap<TMetaVar,Type> unifications = new THashMap<TMetaVar,Type>();
  70         Type requiredType = getType();
  71         if(DEBUG)
  72             System.out.println("EAmbigious.filterActive with " + requiredType);
  73         for(int i=0;i<alternatives.length;++i)
  74             if(active[i]) {
  75                 unifications.clear();
  76                 Type alternativeType = Types.instantiateAndStrip(alternatives[i].getType());
  77                 if(DEBUG)
  78                     System.out.println("    " + alternativeType);
  79                 if(!Skeletons.areSkeletonsCompatible(unifications, alternativeType, requiredType)) {
  80                     active[i] = false;
  81                     --activeCount;
  82                 }
  83             }
  84         if(DEBUG)
  85             System.out.println("    activeCount = " + activeCount);
  86     }
  87
  88     private String getNoMatchDescription(Type requiredType) {
  89         StringBuilder b = new StringBuilder();
  90         b.append("Expected <");
  91         requiredType.toString(new TypeUnparsingContext(), b);
  92         b.append(">, but no alteratives match the type: ");
  93         for(int i=0;i<alternatives.length;++i) {
  94             b.append("\n    ");
  95             b.append(alternatives[i]);
  96             b.append(" :: ");
  97             alternatives[i].getType().toString(new TypeUnparsingContext(), b);
  98         }
  99         b.append('.');
 100         return b.toString();
 101     }
 102
 103     private String getAmbiguousDescription(Type requiredType) {
 104         StringBuilder b = new StringBuilder();
 105         b.append("Expected <");
 106         requiredType.toString(new TypeUnparsingContext(), b);
 107         b.append(">, but multiple values match the type: ");
 108         for(int i=0;i<alternatives.length;++i) {
 109             b.append("\n    ");
 110             b.append(alternatives[i]);
 111             b.append(" :: ");
 112             alternatives[i].getType().toString(new TypeUnparsingContext(), b);
 113         }
 114         b.append('.');
 115         return b.toString();
 116     }
 117
 118
 119     private void resolveTo(int i) {
 120         if(DEBUG)
 121             System.out.println("EAmbigious.resolve to " + alternatives[i]);
 122         resolvedExpression = context.instantiate(alternatives[i].realize());
 123         Type requiredType = getType();
 124         try {
 125             Types.unify(resolvedExpression.getType(), requiredType);
 126         } catch (UnificationException e) {
 127             context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 128         }
 129     }
 130
 131     private void listenType() {
 132         if(DEBUG)
 133             System.out.println("EAmbigious.listenType " + getType());
 134         new TypeListener() {
 135             @Override
 136             public void notifyAboutChange() {
 137                 if(DEBUG)
 138                     System.out.println("EAmbigious.notifyAboutChange " + getType());
 139                 Type requiredType = getType();
 140                 filterActive();
 141                 if(activeCount == 0) {
 142                     context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 143                     return;
 144                 }
 145                 else if(activeCount == 1) {
 146                     for(int i=0;i<alternatives.length;++i)
 147                         if(active[i]) {
 148                             resolveTo(i);
 149                             return;
 150                         }
 151                 }
 152                 Type commonType = getCommonSkeleton();
 153                 try {
 154                     Skeletons.unifySkeletons(requiredType, commonType);
 155                     listenType();
 156                 } catch (UnificationException e) {
 157                     context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 158                 }
 159             }
 160         }.listenSkeleton(getType());
 161     }
 162
 163     @Override
 164     public Expression inferType(TypingContext context) {
 165         this.context = context;
 166         context.overloadedExpressions.add(this);
 167         setType(getCommonSkeleton());
 168         listenType();
 169         return this;
 170     }
 171
 172     @Override
 173     public void collectFreeVariables(THashSet<Variable> vars) {
 174     }
 175
 176     @Override
 177     public Expression resolve(TranslationContext context) {
 178         throw new InternalCompilerError("EAmbiguousConstant should not exist in resolve phase.");
 179     }
 180
 181     @Override
 182     public void setLocationDeep(long loc) {
 183         if(location == Locations.NO_LOCATION)
 184             location = loc;
 185     }
 186
 187     @Override
 188     public void collectEffects(THashSet<Type> effects) {
 189         // TODO Auto-generated method stub
 190     }
 191
 192     @Override
 193     public void accept(ExpressionVisitor visitor) {
 194         // TODO Auto-generated method stub
 195     }
 196
 197     @Override
 198     public Expression simplify(SimplificationContext context) {
 199         if(resolvedExpression != null)
 200             return resolvedExpression;
 201         else {
 202             context.getErrorLog().log(location, getAmbiguousDescription(getType()));
 203             return this;
 204         }
 205     }
 206
 207     public void assertResolved(ErrorLog errorLog) {
 208         if(resolvedExpression == null)
 209             errorLog.log(location, getAmbiguousDescription(getType()));
 210     }
 211
 212     @Override
 213     public Expression accept(ExpressionTransformer transformer) {
 214         return transformer.transform(this);
 215     }
 216
 217 }