bundles/org.simantics.db.layer0/src/org/simantics/db/layer0/scl/AbstractExpressionCompilationRequest.java

   1 package org.simantics.db.layer0.scl;
   2
   3 import gnu.trove.map.hash.THashMap;
   4
   5 import java.util.ArrayList;
   6 import java.util.List;
   7
   8 import org.simantics.db.ReadGraph;
   9 import org.simantics.db.exception.DatabaseException;
  10 import org.simantics.db.exception.RuntimeDatabaseException;
  11 import org.simantics.db.request.Read;
  12 import org.simantics.scl.compiler.common.names.Name;
  13 import org.simantics.scl.compiler.constants.StringConstant;
  14 import org.simantics.scl.compiler.elaboration.expressions.EApply;
  15 import org.simantics.scl.compiler.elaboration.expressions.EConstant;
  16 import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
  17 import org.simantics.scl.compiler.elaboration.expressions.ESimpleLet;
  18 import org.simantics.scl.compiler.elaboration.expressions.EVariable;
  19 import org.simantics.scl.compiler.elaboration.expressions.Expression;
  20 import org.simantics.scl.compiler.elaboration.expressions.Variable;
  21 import org.simantics.scl.compiler.environment.AbstractLocalEnvironment;
  22 import org.simantics.scl.compiler.environment.Environment;
  23 import org.simantics.scl.compiler.environment.LocalEnvironment;
  24 import org.simantics.scl.compiler.errors.CompilationError;
  25 import org.simantics.scl.compiler.runtime.RuntimeEnvironment;
  26 import org.simantics.scl.compiler.top.ExpressionEvaluator;
  27 import org.simantics.scl.compiler.top.SCLExpressionCompilationException;
  28 import org.simantics.scl.compiler.types.TCon;
  29 import org.simantics.scl.compiler.types.Type;
  30 import org.simantics.scl.compiler.types.Types;
  31 import org.simantics.scl.compiler.types.exceptions.MatchException;
  32 import org.simantics.scl.compiler.types.kinds.Kinds;
  33 import org.simantics.scl.compiler.types.util.MultiFunction;
  34 import org.simantics.scl.runtime.SCLContext;
  35 import org.simantics.scl.runtime.function.Function1;
  36 import org.simantics.utils.datastructures.Pair;
  37
  38 /**
  39  * <p>This is a base implementation for compiling expressions stored into
  40  * graph. It provides a skeleton and a set of methods that must be
  41  * implemented to get a concrete compilation request.
  42  *
  43  * <p>The request returns an SCL function with type {@code EvaluationContext -> Result}
  44  * where {@code EvaluationContext} is the type given by {@link #getContextVariableType()}
  45  * and {@code Result} is the type of the expression that can be optionally restricted
  46  * by {@link #getExpectedType(ReadGraph, AbstractExpressionCompilationContext)}.
  47  *
  48  * <p>Compilation calls {@link #getCompilationContext(ReadGraph)} to read all information
  49  * that is needed about the context of the resource during compilation. The result must
  50  * extend the type {@link AbstractExpressionCompilationContext} including at least information about
  51  * {@link RuntimeEnvironment}.
  52  *
  53  * <p>Compilation calls {@link #getVariableAccessExpression(ReadGraph, AbstractExpressionCompilationContext, Variable, String)}
  54  * to get access to local environment. The method may return null if the variable is not defined.
  55  *
  56  * @author Hannu Niemist&ouml;
  57  *
  58  * @param <Context>
  59  */
  60 public abstract class AbstractExpressionCompilationRequest<CompilationContext extends AbstractExpressionCompilationContext,EvaluationContext>
  61 implements Read<Function1<EvaluationContext,Object>> {
  62
  63     protected static final Type RESOURCE = Types.con("Simantics/DB", "Resource");
  64     protected static final Type VARIABLE = Types.con("Simantics/Variables", "Variable");
  65     protected static Name PROPERTY_VALUE = Name.create("Simantics/Variables", "propertyValue");
  66     protected static Name VARIABLE_PARENT = Name.create("Simantics/Variables", "variableParent");
  67     protected static Name FROM_DOUBLE = Name.create("Prelude", "fromDouble");
  68     protected static Name TO_DOUBLE = Name.create("Prelude", "toDouble");
  69     protected static Name FROM_DYNAMIC = Name.create("Prelude", "fromDynamic");
  70
  71     private static final Type DEFAULT_EXPECTED_EFFECT = Types.union(new Type[] {Types.PROC, Types.READ_GRAPH});
  72
  73     /**
  74      * Returns the expression that will be compiled in textual form.
  75      */
  76     protected abstract String getExpressionText(ReadGraph graph) throws DatabaseException;
  77     /**
  78      * Returns the context that is used for the compilation of the expression. The context
  79      * contains information about available constants and variables.
  80      */
  81     protected abstract CompilationContext getCompilationContext(ReadGraph graph) throws DatabaseException;
  82     /**
  83      * This should return the SCL type corresponding to generic type parameter {@code EvaluationContext}.
  84      */
  85     protected abstract Type getContextVariableType();
  86     /**
  87      * Returns <code>null</code>, if variable {@code name} is not defined.
  88      */
  89     protected abstract Expression getVariableAccessExpression(ReadGraph graph,
  90             CompilationContext context, Variable contextVariable, String name) throws DatabaseException;
  91
  92     protected Type getExpectedType(ReadGraph graph, CompilationContext context) throws DatabaseException {
  93         return Types.metaVar(Kinds.STAR);
  94     }
  95
  96     protected Type getExpectedEffect(ReadGraph graph, CompilationContext context) throws DatabaseException {
  97         return DEFAULT_EXPECTED_EFFECT;
  98     }
  99
 100     private ExpressionEvaluator prepareEvaluator(final ReadGraph graph, final CompilationContext context, Type expectedType) throws DatabaseException {
 101         final Variable contextVariable = new Variable("context", getContextVariableType());
 102         LocalEnvironment localEnvironment = new AbstractLocalEnvironment() {
 103             THashMap<String,Pair<Variable,Expression>> precalculatedVariables = new THashMap<String,Pair<Variable,Expression>>();
 104             @Override
 105             public Expression resolve(Environment environment, String localName) {
 106                 Pair<Variable,Expression> precalculatedVariable = precalculatedVariables.get(localName);
 107                 if(precalculatedVariable == null) {
 108                     try {
 109                         Expression value = getVariableAccessExpression(graph, context, contextVariable, localName);
 110                         if(value == null)
 111                             return null;
 112                         Variable variable = new Variable(localName);
 113                         precalculatedVariable = Pair.make(variable, value);
 114                         precalculatedVariables.put(localName, precalculatedVariable);
 115                     } catch (DatabaseException e) {
 116                         throw new RuntimeDatabaseException(e);
 117                     }
 118                 }
 119                 return new EVariable(precalculatedVariable.first);
 120             }
 121             @Override
 122             public Expression preDecorateExpression(Expression expression) {
 123                 for(Pair<Variable,Expression> precalculatedVariable : precalculatedVariables.values())
 124                     expression = new ESimpleLet(precalculatedVariable.first, precalculatedVariable.second, expression);
 125                 return expression;
 126             }
 127             @Override
 128             protected Variable[] getContextVariables() {
 129                 return new Variable[] { contextVariable };
 130             }
 131         };
 132
 133         String expressionText = getExpressionText(graph);
 134         return new ExpressionEvaluator(context.runtimeEnvironment, expressionText)
 135             .localEnvironment(localEnvironment)
 136             .expectedType(expectedType)
 137             .parseAsBlock(parseAsBlock());
 138     }
 139
 140     protected boolean parseAsBlock() {
 141         return false;
 142     }
 143
 144     private Function1<EvaluationContext, Object> eval(ExpressionEvaluator evaluator, ReadGraph graph) throws DatabaseException {
 145         Object oldGraph = SCLContext.getCurrent().put("graph", graph);
 146         try {
 147             return (Function1<EvaluationContext,Object>)evaluator.eval();
 148         } catch(RuntimeDatabaseException e) {
 149             e.printStackTrace();
 150             if(e.getCause() instanceof DatabaseException)
 151                 throw (DatabaseException)e.getCause();
 152             else
 153                 throw e;
 154         } catch (SCLExpressionCompilationException e) {
 155             StringBuilder b = new StringBuilder();
 156             b.append("Couldn't compile '");
 157             b.append(evaluator.getExpressionText());
 158             b.append("':\n");
 159             StringBuilder b2 = new StringBuilder();
 160             for(CompilationError error : e.getErrors()) {
 161                 b2.append(error.description);
 162                 b2.append('\n');
 163             }
 164             System.err.println(b.toString() + b2.toString());
 165             throw new SCLDatabaseException(b.toString()+b2.toString(), b2.toString(), e.getErrors());
 166         } catch(Throwable e) {
 167             // Should not happen!
 168             e.printStackTrace();
 169             throw new RuntimeException(e);
 170         } finally {
 171             SCLContext.getCurrent().put("graph", oldGraph);
 172         }
 173     }
 174
 175     public List<TCon> getExpressionEffects(final ReadGraph graph) throws DatabaseException {
 176         CompilationContext context = getCompilationContext(graph);
 177         Type type = Types.metaVar(Kinds.STAR);
 178         eval(prepareEvaluator(graph, context, type), graph);
 179
 180         try {
 181             MultiFunction mfun = Types.matchFunction(type, 1);
 182             ArrayList<TCon> concreteEffects = new ArrayList<TCon>();
 183             mfun.effect.collectConcreteEffects(concreteEffects);
 184             return concreteEffects;
 185         } catch(MatchException e) {
 186             // Should not happen!
 187             e.printStackTrace();
 188             throw new RuntimeException(e);
 189         }
 190     }
 191
 192     @SuppressWarnings("unchecked")
 193     @Override
 194     public Function1<EvaluationContext,Object> perform(final ReadGraph graph) throws DatabaseException {
 195         CompilationContext context = getCompilationContext(graph);
 196         return eval(prepareEvaluator(graph, context, getExpectedType(graph, context)), graph);
 197     }
 198
 199     protected static Expression getProperty(Environment environment, Expression variable, String propertyName, Type type) {
 200         return new EApply(
 201                 new EConstant(environment.getValue(FROM_DYNAMIC), type),
 202                 new EApply(
 203                         new EConstant(environment.getValue(PROPERTY_VALUE), Types.DYNAMIC),
 204                         variable,
 205                         new ELiteral(new StringConstant(propertyName))));
 206     }
 207
 208     protected static Expression getPropertyFlexible(Environment environment, Expression variable, String propertyName, Type type) {
 209         return makeTypeFlexible(environment, getProperty(environment, variable, propertyName, type), type);
 210     }
 211
 212     protected static Expression makeTypeFlexible(Environment environment, Expression base, Type originalType) {
 213         if(originalType.equals(Types.DOUBLE))
 214             return new EApply(
 215                     new EConstant(environment.getValue(FROM_DOUBLE)),
 216                     base);
 217         else if(originalType.equals(Types.FLOAT))
 218             return new EApply(
 219                     new EConstant(environment.getValue(FROM_DOUBLE)),
 220                     new EApply(
 221                             new EConstant(environment.getValue(TO_DOUBLE), Types.FLOAT),
 222                             base));
 223         else
 224             return base;
 225     }
 226 }