gerrit.simantics Code Review - simantics/platform.git/blob

   1 package org.simantics.scl.compiler.elaboration.expressions;
   2
   3 import org.simantics.scl.compiler.elaboration.contexts.ReplaceContext;
   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.Locations;
   8 import org.simantics.scl.compiler.types.Type;
   9 import org.simantics.scl.compiler.types.Types;
  10 import org.simantics.scl.compiler.types.exceptions.MatchException;
  11 import org.simantics.scl.compiler.types.exceptions.UnificationException;
  12 import org.simantics.scl.compiler.types.kinds.Kinds;
  13 import org.simantics.scl.compiler.types.util.MultiFunction;
  14
  15 import gnu.trove.map.hash.TObjectIntHashMap;
  16 import gnu.trove.set.hash.THashSet;
  17 import gnu.trove.set.hash.TIntHashSet;
  18
  19 public class ELambda extends SimplifiableExpression {
  20     public Case[] cases;
  21     Type effect = Types.NO_EFFECTS;
  22
  23     public ELambda(Case[] cases) {
  24         this.cases = cases;
  25     }
  26
  27     public ELambda(Case case_) {
  28         this(new Case[] {case_});
  29     }
  30
  31     public ELambda(long loc, Case ... cases) {
  32         super(loc);
  33         this.cases = cases;
  34     }
  35
  36     public ELambda(long loc, Expression pat, Expression exp) {
  37         this(loc, new Case(new Expression[] {pat}, exp));
  38     }
  39
  40     @Override
  41     public void collectVars(TObjectIntHashMap<Variable> allVars,
  42             TIntHashSet vars) {
  43         for(Case case_ : cases)
  44             case_.collectVars(allVars, vars);
  45     }
  46
  47     public Expression decomposeMatching() {
  48         Expression[] patterns = cases[0].patterns;
  49         int arity = patterns.length;
  50
  51         // Simple cases
  52         if(cases.length == 1 &&
  53                 !(cases[0].value instanceof GuardedExpressionGroup)) {
  54             boolean noMatchingNeeded = true;
  55             for(int i=0;i<arity;++i)
  56                 if(!(patterns[i] instanceof EVariable)) {
  57                     noMatchingNeeded = false;
  58                     break;
  59                 }
  60             if(noMatchingNeeded) {
  61                 Expression decomposed = cases[0].value.decomposeMatching();
  62                 Type effect = this.effect;
  63                 for(int i=arity-1;i>=0;--i) {
  64                     Variable var = ((EVariable)patterns[i]).getVariable();
  65                     decomposed = new ESimpleLambda(getLocation(), var, effect, decomposed);
  66                     effect = Types.NO_EFFECTS;
  67                 }
  68                 return decomposed;
  69             }
  70         }
  71
  72         // Complex case
  73         Variable[] vars = new Variable[arity];
  74         Expression[] scrutinee = new Expression[arity];
  75         for(int i=0;i<arity;++i) {
  76             vars[i] = new Variable("temp" + i);
  77             Type type = patterns[i].getType();
  78             vars[i].setType(type);
  79             scrutinee[i] = new EVariable(getLocation(), vars[i]);
  80             scrutinee[i].setType(type);
  81         }
  82         Expression decomposed = new EMatch(getLocation(), scrutinee, cases);
  83         Type curEffect = this.effect;
  84         for(int i=arity-1;i>=0;--i) {
  85             decomposed = new ESimpleLambda(getLocation(), vars[i], curEffect, decomposed);
  86             curEffect = Types.NO_EFFECTS;
  87         }
  88         return decomposed;
  89     }
  90
  91         @Override
  92         protected void updateType() throws MatchException {
  93             setType(Types.functionE(Types.getTypes(cases[0].patterns), effect, cases[0].value.getType()));
  94         }
  95
  96         @Override
  97         public Expression simplify(SimplificationContext context) {
  98             return decomposeMatching().simplify(context);
  99         }
 100
 101     @Override
 102     public void collectFreeVariables(THashSet<Variable> vars) {
 103         for(Case case_ : cases)
 104             case_.collectFreeVariables(vars);
 105     }
 106
 107     @Override
 108     public Expression resolve(TranslationContext context) {
 109         for(Case case_ : cases)
 110             case_.resolve(context);
 111         return this;
 112     }
 113
 114     @Override
 115     public void setLocationDeep(long loc) {
 116         if(location == Locations.NO_LOCATION) {
 117             location = loc;
 118             for(Case case_ : cases)
 119                 case_.setLocationDeep(loc);
 120         }
 121     }
 122
 123     @Override
 124     public Expression replace(ReplaceContext context) {
 125         Case[] newCases = new Case[cases.length];
 126         for(int i=0;i<cases.length;++i)
 127             newCases[i] = cases[i].replace(context);
 128         return new ELambda(newCases);
 129     }
 130
 131     public Case[] getCases() {
 132         return cases;
 133     }
 134
 135     public Expression checkBasicType(TypingContext context, Type requiredType) {
 136         int arity = cases[0].patterns.length;
 137         MultiFunction mfun;
 138         try {
 139             mfun = Types.unifyFunction(requiredType, arity);
 140         } catch (UnificationException e) {
 141             int requiredArity = Types.getArity(requiredType);
 142             context.getErrorLog().log(cases[0].getLhs(), "Arity is " + requiredArity + " but "
 143                     + arity + " patterns have been given.");
 144             setType(Types.metaVar(Kinds.STAR));
 145             return this;
 146         }
 147
 148         effect = mfun.effect;
 149         context.pushEffectUpperBound(location, mfun.effect);
 150         for(Case case_ : cases)
 151             case_.checkType(context, mfun.parameterTypes,  mfun.returnType);
 152         context.popEffectUpperBound();
 153         return this;
 154     }
 155
 156     @Override
 157     public Expression inferType(TypingContext context) {
 158         int arity = cases[0].patterns.length;
 159         effect = Types.metaVar(Kinds.EFFECT);
 160         context.pushEffectUpperBound(location, effect);
 161         Type[] parameterTypes = new Type[arity];
 162         for(int i=0;i<parameterTypes.length;++i)
 163             parameterTypes[i] = Types.metaVar(Kinds.STAR);
 164         Type requiredType = Types.metaVar(Kinds.STAR);
 165         for(Case case_ : cases)
 166             case_.checkType(context, parameterTypes, requiredType);
 167         context.popEffectUpperBound();
 168         return this;
 169     }
 170
 171     @Override
 172     public boolean isEffectful() {
 173         return false;
 174     }
 175
 176     @Override
 177     public void accept(ExpressionVisitor visitor) {
 178         visitor.visit(this);
 179     }
 180
 181     @Override
 182     public Expression accept(ExpressionTransformer transformer) {
 183         return transformer.transform(this);
 184     }
 185
 186     @Override
 187     public int getSyntacticFunctionArity() {
 188         int result = 0;
 189         for(Case case_ : cases)
 190             result = Math.max(result, case_.patterns.length + case_.value.getSyntacticFunctionArity());
 191         return result;
 192     }
 193
 194 }