bundles/org.simantics.scl.compiler/src/org/simantics/scl/compiler/elaboration/chr/CHRRule.java

   1 package org.simantics.scl.compiler.elaboration.chr;
   2
   3 import java.util.ArrayList;
   4 import java.util.HashMap;
   5
   6 import org.simantics.scl.compiler.compilation.CompilationContext;
   7 import org.simantics.scl.compiler.elaboration.chr.plan.CHRSearchPlan;
   8 import org.simantics.scl.compiler.elaboration.chr.planning.QueryPlanningContext;
   9 import org.simantics.scl.compiler.elaboration.chr.relations.CHRConstraint;
  10 import org.simantics.scl.compiler.elaboration.contexts.SimplificationContext;
  11 import org.simantics.scl.compiler.elaboration.contexts.TranslationContext;
  12 import org.simantics.scl.compiler.elaboration.contexts.TypingContext;
  13 import org.simantics.scl.compiler.elaboration.expressions.EAsPattern;
  14 import org.simantics.scl.compiler.elaboration.expressions.EVariable;
  15 import org.simantics.scl.compiler.elaboration.expressions.Expression;
  16 import org.simantics.scl.compiler.elaboration.expressions.ExpressionVisitor;
  17 import org.simantics.scl.compiler.elaboration.expressions.Variable;
  18 import org.simantics.scl.compiler.elaboration.expressions.printing.ExpressionToStringVisitor;
  19 import org.simantics.scl.compiler.elaboration.expressions.visitors.StandardExpressionVisitor;
  20 import org.simantics.scl.compiler.errors.Locations;
  21 import org.simantics.scl.compiler.internal.parsing.Symbol;
  22 import org.simantics.scl.compiler.types.Types;
  23 import org.simantics.scl.compiler.types.kinds.Kinds;
  24
  25 import gnu.trove.map.hash.TObjectIntHashMap;
  26 import gnu.trove.set.hash.TIntHashSet;
  27
  28 public class CHRRule extends Symbol {
  29     public CHRRuleset parentRuleset;
  30     public int priority;
  31     public CHRQuery head;
  32     public CHRQuery body;
  33     public Variable[] existentialVariables;
  34
  35     // Analysis
  36     //public int firstPriorityExecuted;
  37     public int lastPriorityExecuted;
  38
  39     // Plans
  40     public ArrayList<CHRSearchPlan> plans = new ArrayList<CHRSearchPlan>();
  41
  42     // Code generation, move to CHRPriority
  43     public String containerClassName;
  44
  45     public CHRRule(long location, CHRQuery head, CHRQuery body, Variable[] existentialVariables) {
  46         this.location = location;
  47         this.head = head;
  48         this.body = body;
  49         this.existentialVariables = existentialVariables;
  50     }
  51
  52     public CHRRule(long location, CHRQuery head, CHRQuery body) {
  53         this(location, head, body, null);
  54     }
  55
  56     public void resolve(TranslationContext context) {
  57         context.pushExistentialFrame();
  58         head.resolve(context);
  59         context.disallowNewExistentials();
  60         body.resolve(context);
  61         existentialVariables = context.popExistentialFrame();
  62
  63         warnForExistentialsUsedOnlyOnce(context);
  64     }
  65
  66     private static final Object NEVER_USED = new Object();
  67
  68     private void warnForExistentialsUsedOnlyOnce(TranslationContext context) {
  69         // Initialize the hash map
  70         HashMap<Variable, Object> usageCount = new HashMap<>(existentialVariables.length);
  71         for(Variable var : existentialVariables)
  72             if(!var.getName().equals("_"))
  73                 usageCount.put(var, NEVER_USED);
  74
  75         // Collect variable uses
  76         ExpressionVisitor visitor = new StandardExpressionVisitor() {
  77             private void handle(Expression expression, Variable variable) {
  78                 Object object = usageCount.remove(variable);
  79                 if(object == NEVER_USED)
  80                     usageCount.put(variable, expression);
  81             }
  82             @Override
  83             public void visit(EVariable expression) {
  84                 if(expression.variable != null)
  85                     handle(expression, expression.variable);
  86             }
  87             @Override
  88             public void visit(EAsPattern expression) {
  89                 expression.pattern.accept(this);
  90                 handle(expression, expression.var);
  91             }
  92         };
  93         head.accept(visitor);
  94         body.accept(visitor);
  95
  96         // Report as warnings
  97         usageCount.forEach((variable, expression_) -> {
  98             if(!(expression_ instanceof Expression))
  99                 return; // Should never happen
 100             Expression expression = (Expression)expression_;
 101             if(context.isExpandedFromWildcard(expression))
 102                 return;
 103
 104             context.getErrorLog().logWarning(expression.location,
 105                     "Existential variable " + variable.getName() + " is referred only once. Replace by _ if this is a wildcard.");
 106         });
 107
 108     }
 109
 110     public void checkType(TypingContext context) {
 111         for(Variable variable : existentialVariables)
 112             variable.setType(Types.metaVar(Kinds.STAR));
 113         head.checkType(context);
 114         body.checkType(context);
 115     }
 116
 117     public void collectVars(TObjectIntHashMap<Variable> allVars, TIntHashSet vars) {
 118         head.collectVars(allVars, vars);
 119         body.collectVars(allVars, vars);
 120     }
 121
 122     public void setLocationDeep(long loc) {
 123         if(location == Locations.NO_LOCATION) {
 124             this.location = loc;
 125             head.setLocationDeep(loc);
 126             body.setLocationDeep(loc);
 127         }
 128     }
 129
 130     public void simplify(SimplificationContext context) {
 131         head.simplify(context);
 132         body.simplify(context);
 133     }
 134
 135     public void compile(CompilationContext compilationContext, CHRConstraint initConstraint) {
 136         boolean hasLocalActiveLiteral = false;
 137         for(int i=0;i<head.literals.length;++i) {
 138             CHRLiteral literal = head.literals[i];
 139             if(literal.passive)
 140                 continue;
 141             CHRConstraint constraint = (CHRConstraint)literal.relation;
 142
 143             Variable activeFact = new Variable("activeFact", constraint.factType);
 144             QueryPlanningContext context = new QueryPlanningContext(compilationContext, existentialVariables);
 145             if(!head.createQueryPlan(context, new EVariable(activeFact), i, initConstraint))
 146                 return;
 147             body.createEnforcePlan(context, priority);
 148             addPlan(new CHRSearchPlan(constraint, activeFact, context.getPlanOps()));
 149
 150             if(constraint.parentRuleset == parentRuleset)
 151                 hasLocalActiveLiteral = true;
 152         }
 153         if(!hasLocalActiveLiteral) {
 154             Variable activeFact = new Variable("activeFact", initConstraint.factType);
 155             QueryPlanningContext context = new QueryPlanningContext(compilationContext, existentialVariables);
 156             if(!head.createQueryPlan(context, new EVariable(activeFact), -1, initConstraint))
 157                 return;
 158             body.createEnforcePlan(context, priority);
 159             /*System.out.println(this);
 160             for(PlanOp planOp : context.getPlanOps())
 161                 System.out.println("    " + planOp);*/
 162             addPlan(new CHRSearchPlan(initConstraint, activeFact, context.getPlanOps()));
 163         }
 164     }
 165
 166     private void addPlan(CHRSearchPlan plan) {
 167         plans.add(plan);
 168     }
 169
 170     public String toString() {
 171         StringBuilder b = new StringBuilder();
 172         ExpressionToStringVisitor visitor = new ExpressionToStringVisitor(b);
 173         visitor.visit(this);
 174         return b.toString();
 175     }
 176
 177 }