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.internal.elaboration.utils.ExpressionDecorator;
  10 import org.simantics.scl.compiler.types.Skeletons;
  11 import org.simantics.scl.compiler.types.TMetaVar;
  12 import org.simantics.scl.compiler.types.Type;
  13 import org.simantics.scl.compiler.types.Types;
  14 import org.simantics.scl.compiler.types.exceptions.MatchException;
  15 import org.simantics.scl.compiler.types.exceptions.UnificationException;
  16 import org.simantics.scl.compiler.types.util.TypeListener;
  17 import org.simantics.scl.compiler.types.util.TypeUnparsingContext;
  18
  19 import gnu.trove.map.hash.THashMap;
  20 import gnu.trove.map.hash.TObjectIntHashMap;
  21 import gnu.trove.set.hash.THashSet;
  22 import gnu.trove.set.hash.TIntHashSet;
  23
  24 public class EAmbiguous extends SimplifiableExpression {
  25     public static final boolean DEBUG = false;
  26
  27     Alternative[] alternatives;
  28     boolean[] active;
  29     int activeCount;
  30     transient TypingContext context;
  31     Expression resolvedExpression;
  32
  33     public abstract static class Alternative {
  34         public abstract Type getType();
  35         public abstract Expression realize();
  36     }
  37
  38     public EAmbiguous(Alternative[] alternatives) {
  39         this.alternatives = alternatives;
  40         this.active = new boolean[alternatives.length];
  41         for(int i=0;i<alternatives.length;++i)
  42             this.active[i] = true;
  43         this.activeCount = alternatives.length;
  44     }
  45
  46     @Override
  47     public void collectRefs(TObjectIntHashMap<Object> allRefs,
  48             TIntHashSet refs) {
  49     }
  50
  51     @Override
  52     public void collectVars(TObjectIntHashMap<Variable> allVars,
  53             TIntHashSet vars) {
  54     }
  55
  56     @Override
  57     public void forVariables(VariableProcedure procedure) {
  58     }
  59
  60     @Override
  61     protected void updateType() throws MatchException {
  62         throw new InternalCompilerError();
  63     }
  64
  65     private Type getCommonSkeleton() {
  66         Type[] types = new Type[activeCount];
  67         for(int i=0,j=0;i<alternatives.length;++i)
  68             if(active[i])
  69                 types[j++] = Types.instantiateAndStrip(alternatives[i].getType());
  70         return Skeletons.commonSkeleton(context.getEnvironment(), types);
  71     }
  72
  73     private void filterActive() {
  74         THashMap<TMetaVar,Type> unifications = new THashMap<TMetaVar,Type>();
  75         Type requiredType = getType();
  76         if(DEBUG)
  77             System.out.println("EAmbigious.filterActive with " + requiredType);
  78         for(int i=0;i<alternatives.length;++i)
  79             if(active[i]) {
  80                 unifications.clear();
  81                 Type alternativeType = Types.instantiateAndStrip(alternatives[i].getType());
  82                 if(DEBUG)
  83                     System.out.println("    " + alternativeType);
  84                 if(!Skeletons.areSkeletonsCompatible(unifications, alternativeType, requiredType)) {
  85                     active[i] = false;
  86                     --activeCount;
  87                 }
  88             }
  89         if(DEBUG)
  90             System.out.println("    activeCount = " + activeCount);
  91     }
  92
  93     private String getNoMatchDescription(Type requiredType) {
  94         StringBuilder b = new StringBuilder();
  95         b.append("Expected <");
  96         requiredType.toString(new TypeUnparsingContext(), b);
  97         b.append(">, but no alteratives match the type: ");
  98         for(int i=0;i<alternatives.length;++i) {
  99             b.append("\n    ");
 100             b.append(alternatives[i]);
 101             b.append(" :: ");
 102             alternatives[i].getType().toString(new TypeUnparsingContext(), b);
 103         }
 104         b.append('.');
 105         return b.toString();
 106     }
 107
 108     private String getAmbiguousDescription(Type requiredType) {
 109         StringBuilder b = new StringBuilder();
 110         b.append("Expected <");
 111         requiredType.toString(new TypeUnparsingContext(), b);
 112         b.append(">, but multiple values match the type: ");
 113         for(int i=0;i<alternatives.length;++i) {
 114             b.append("\n    ");
 115             b.append(alternatives[i]);
 116             b.append(" :: ");
 117             alternatives[i].getType().toString(new TypeUnparsingContext(), b);
 118         }
 119         b.append('.');
 120         return b.toString();
 121     }
 122
 123
 124     private void resolveTo(int i) {
 125         if(DEBUG)
 126             System.out.println("EAmbigious.resolve to " + alternatives[i]);
 127         resolvedExpression = context.instantiate(alternatives[i].realize());
 128         Type requiredType = getType();
 129         try {
 130             Types.unify(resolvedExpression.getType(), requiredType);
 131         } catch (UnificationException e) {
 132             context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 133         }
 134     }
 135
 136     private void listenType() {
 137         if(DEBUG)
 138             System.out.println("EAmbigious.listenType " + getType());
 139         new TypeListener() {
 140             @Override
 141             public void notifyAboutChange() {
 142                 if(DEBUG)
 143                     System.out.println("EAmbigious.notifyAboutChange " + getType());
 144                 Type requiredType = getType();
 145                 filterActive();
 146                 if(activeCount == 0) {
 147                     context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 148                     return;
 149                 }
 150                 else if(activeCount == 1) {
 151                     for(int i=0;i<alternatives.length;++i)
 152                         if(active[i]) {
 153                             resolveTo(i);
 154                             return;
 155                         }
 156                 }
 157                 Type commonType = getCommonSkeleton();
 158                 try {
 159                     Skeletons.unifySkeletons(requiredType, commonType);
 160                     listenType();
 161                 } catch (UnificationException e) {
 162                     context.getErrorLog().log(location, getNoMatchDescription(requiredType));
 163                 }
 164             }
 165         }.listenSkeleton(getType());
 166     }
 167
 168     @Override
 169     public Expression inferType(TypingContext context) {
 170         this.context = context;
 171         context.overloadedExpressions.add(this);
 172         setType(getCommonSkeleton());
 173         listenType();
 174         return this;
 175     }
 176
 177     @Override
 178     public void collectFreeVariables(THashSet<Variable> vars) {
 179     }
 180
 181     @Override
 182     public Expression resolve(TranslationContext context) {
 183         throw new InternalCompilerError("EAmbiguousConstant should not exist in resolve phase.");
 184     }
 185
 186     @Override
 187     public void setLocationDeep(long loc) {
 188         if(location == Locations.NO_LOCATION)
 189             location = loc;
 190     }
 191
 192     @Override
 193     public Expression decorate(ExpressionDecorator decorator) {
 194         return this;
 195     }
 196
 197     @Override
 198     public void collectEffects(THashSet<Type> effects) {
 199         // TODO Auto-generated method stub
 200     }
 201
 202     @Override
 203     public void accept(ExpressionVisitor visitor) {
 204         // TODO Auto-generated method stub
 205     }
 206
 207     @Override
 208     public Expression simplify(SimplificationContext context) {
 209         if(resolvedExpression != null)
 210             return resolvedExpression;
 211         else {
 212             context.getErrorLog().log(location, getAmbiguousDescription(getType()));
 213             return this;
 214         }
 215     }
 216
 217     public void assertResolved(ErrorLog errorLog) {
 218         if(resolvedExpression == null)
 219             errorLog.log(location, getAmbiguousDescription(getType()));
 220     }
 221
 222     @Override
 223     public Expression accept(ExpressionTransformer transformer) {
 224         return transformer.transform(this);
 225     }
 226
 227 }