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

   1 package org.simantics.db.layer0.scl;
   2
   3 import java.util.ArrayList;
   4 import java.util.List;
   5
   6 import org.simantics.databoard.Bindings;
   7 import org.simantics.db.ReadGraph;
   8 import org.simantics.db.Resource;
   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.layer0.Layer0;
  13 import org.simantics.scl.compiler.common.names.Name;
  14 import org.simantics.scl.compiler.constants.StringConstant;
  15 import org.simantics.scl.compiler.elaboration.expressions.EApply;
  16 import org.simantics.scl.compiler.elaboration.expressions.EConstant;
  17 import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
  18 import org.simantics.scl.compiler.elaboration.expressions.ESimpleLet;
  19 import org.simantics.scl.compiler.elaboration.expressions.EVariable;
  20 import org.simantics.scl.compiler.elaboration.expressions.Expression;
  21 import org.simantics.scl.compiler.elaboration.expressions.Variable;
  22 import org.simantics.scl.compiler.environment.AbstractLocalEnvironment;
  23 import org.simantics.scl.compiler.environment.Environment;
  24 import org.simantics.scl.compiler.environment.LocalEnvironment;
  25 import org.simantics.scl.compiler.errors.CompilationError;
  26 import org.simantics.scl.compiler.runtime.RuntimeEnvironment;
  27 import org.simantics.scl.compiler.top.ExpressionEvaluator;
  28 import org.simantics.scl.compiler.top.SCLExpressionCompilationException;
  29 import org.simantics.scl.compiler.types.TCon;
  30 import org.simantics.scl.compiler.types.Type;
  31 import org.simantics.scl.compiler.types.Types;
  32 import org.simantics.scl.compiler.types.exceptions.MatchException;
  33 import org.simantics.scl.compiler.types.kinds.Kinds;
  34 import org.simantics.scl.compiler.types.util.MultiFunction;
  35 import org.simantics.scl.runtime.SCLContext;
  36 import org.simantics.scl.runtime.function.Function1;
  37 import org.simantics.utils.datastructures.Pair;
  38 import org.slf4j.Logger;
  39 import org.slf4j.LoggerFactory;
  40
  41 import gnu.trove.map.hash.THashMap;
  42
  43 /**
  44  * <p>This is a base implementation for compiling expressions stored into
  45  * graph. It provides a skeleton and a set of methods that must be
  46  * implemented to get a concrete compilation request.
  47  *
  48  * <p>The request returns an SCL function with type {@code EvaluationContext -> Result}
  49  * where {@code EvaluationContext} is the type given by {@link #getContextVariableType()}
  50  * and {@code Result} is the type of the expression that can be optionally restricted
  51  * by {@link #getExpectedType(ReadGraph, AbstractExpressionCompilationContext)}.
  52  *
  53  * <p>Compilation calls {@link #getCompilationContext(ReadGraph)} to read all information
  54  * that is needed about the context of the resource during compilation. The result must
  55  * extend the type {@link AbstractExpressionCompilationContext} including at least information about
  56  * {@link RuntimeEnvironment}.
  57  *
  58  * <p>Compilation calls {@link #getVariableAccessExpression(ReadGraph, AbstractExpressionCompilationContext, Variable, String)}
  59  * to get access to local environment. The method may return null if the variable is not defined.
  60  *
  61  * @author Hannu Niemist&ouml;
  62  *
  63  * @param <Context>
  64  */
  65 public abstract class AbstractExpressionCompilationRequest<CompilationContext extends AbstractExpressionCompilationContext,EvaluationContext>
  66 implements Read<Function1<EvaluationContext,Object>> {
  67
  68     private static final Logger LOGGER = LoggerFactory.getLogger(AbstractExpressionCompilationRequest.class);
  69
  70     protected static final Type RESOURCE = Types.con("Simantics/DB", "Resource");
  71     protected static final Type VARIABLE = Types.con("Simantics/Variables", "Variable");
  72     protected static Name PROPERTY_VALUE = Name.create("Simantics/Variables", "propertyValue");
  73     protected static Name VARIABLE_PARENT = Name.create("Simantics/Variables", "variableParent");
  74     protected static Name FROM_DOUBLE = Name.create("Prelude", "fromDouble");
  75     protected static Name TO_DOUBLE = Name.create("Prelude", "toDouble");
  76     protected static Name FROM_DYNAMIC = Name.create("Prelude", "fromDynamic");
  77
  78     private static final Type DEFAULT_EXPECTED_EFFECT = Types.union(new Type[] {Types.PROC, Types.READ_GRAPH});
  79
  80     /**
  81      * Returns the expression that will be compiled in textual form.
  82      */
  83     protected abstract String getExpressionText(ReadGraph graph) throws DatabaseException;
  84     /**
  85      * Returns the context that is used for the compilation of the expression. The context
  86      * contains information about available constants and variables.
  87      */
  88     protected abstract CompilationContext getCompilationContext(ReadGraph graph) throws DatabaseException;
  89     /**
  90      * This should return the SCL type corresponding to generic type parameter {@code EvaluationContext}.
  91      */
  92     protected abstract Type getContextVariableType();
  93     /**
  94      * Returns <code>null</code>, if variable {@code name} is not defined.
  95      */
  96     protected abstract Expression getVariableAccessExpression(ReadGraph graph,
  97             CompilationContext context, Variable contextVariable, String name) throws DatabaseException;
  98
  99     protected Type getExpectedType(ReadGraph graph, CompilationContext context) throws DatabaseException {
 100         return Types.metaVar(Kinds.STAR);
 101     }
 102
 103     protected Type getExpectedEffect(ReadGraph graph, CompilationContext context) throws DatabaseException {
 104         return DEFAULT_EXPECTED_EFFECT;
 105     }
 106
 107     private ExpressionEvaluator prepareEvaluator(final ReadGraph graph, final CompilationContext context, Type expectedType) throws DatabaseException {
 108         final Variable contextVariable = new Variable("context", getContextVariableType());
 109         LocalEnvironment localEnvironment = new AbstractLocalEnvironment() {
 110             THashMap<String,Pair<Variable,Expression>> precalculatedVariables = new THashMap<String,Pair<Variable,Expression>>();
 111             @Override
 112             public Expression resolve(Environment environment, String localName) {
 113                 Pair<Variable,Expression> precalculatedVariable = precalculatedVariables.get(localName);
 114                 if(precalculatedVariable == null) {
 115                     try {
 116                         Expression value = getVariableAccessExpression(graph, context, contextVariable, localName);
 117                         if(value == null)
 118                             return null;
 119                         Variable variable = new Variable(localName);
 120                         precalculatedVariable = Pair.make(variable, value);
 121                         precalculatedVariables.put(localName, precalculatedVariable);
 122                     } catch (DatabaseException e) {
 123                         throw new RuntimeDatabaseException(e);
 124                     }
 125                 }
 126                 return new EVariable(precalculatedVariable.first);
 127             }
 128             @Override
 129             public Expression preDecorateExpression(Expression expression) {
 130                 for(Pair<Variable,Expression> precalculatedVariable : precalculatedVariables.values())
 131                     expression = new ESimpleLet(precalculatedVariable.first, precalculatedVariable.second, expression);
 132                 return expression;
 133             }
 134             @Override
 135             protected Variable[] getContextVariables() {
 136                 return new Variable[] { contextVariable };
 137             }
 138         };
 139
 140         String expressionText = getExpressionText(graph);
 141         return new ExpressionEvaluator(context.runtimeEnvironment, expressionText)
 142             .localEnvironment(localEnvironment)
 143             .expectedType(expectedType)
 144             .parseAsBlock(parseAsBlock());
 145     }
 146
 147     protected boolean parseAsBlock() {
 148         return false;
 149     }
 150
 151     @SuppressWarnings("unchecked")
 152     private Function1<EvaluationContext, Object> eval(ExpressionEvaluator evaluator, ReadGraph graph) throws DatabaseException {
 153         Object oldGraph = SCLContext.getCurrent().put("graph", graph);
 154         try {
 155             return (Function1<EvaluationContext,Object>)evaluator.eval();
 156         } catch(RuntimeDatabaseException e) {
 157             LOGGER.error("Failed to evaluate SCL expression", e);
 158             if(e.getCause() instanceof DatabaseException)
 159                 throw (DatabaseException)e.getCause();
 160             else
 161                 throw e;
 162         } catch (SCLExpressionCompilationException e) {
 163             StringBuilder b = new StringBuilder();
 164             b.append("Couldn't compile '");
 165             b.append(evaluator.getExpressionText());
 166             b.append("':\n");
 167             StringBuilder b2 = new StringBuilder();
 168             for(CompilationError error : e.getErrors()) {
 169                 b2.append(error.description);
 170                 b2.append('\n');
 171             }
 172             System.err.println(b.toString() + b2.toString());
 173             throw new SCLDatabaseException(b.toString()+b2.toString(), b2.toString(), e.getErrors());
 174         } catch(Throwable e) {
 175             // Should not happen!
 176             LOGGER.error("This error should never happen", e);
 177             throw new RuntimeException(e);
 178         } finally {
 179             SCLContext.getCurrent().put("graph", oldGraph);
 180         }
 181     }
 182
 183     public List<TCon> getExpressionEffects(final ReadGraph graph) throws DatabaseException {
 184         CompilationContext context = getCompilationContext(graph);
 185         Type type = Types.metaVar(Kinds.STAR);
 186         eval(prepareEvaluator(graph, context, type), graph);
 187
 188         try {
 189             MultiFunction mfun = Types.matchFunction(type, 1);
 190             ArrayList<TCon> concreteEffects = new ArrayList<TCon>();
 191             mfun.effect.collectConcreteEffects(concreteEffects);
 192             return concreteEffects;
 193         } catch(MatchException e) {
 194             // Should not happen!
 195             LOGGER.error("Failed to get expression effects", e);
 196             throw new RuntimeException(e);
 197         }
 198     }
 199
 200     @Override
 201     public Function1<EvaluationContext,Object> perform(final ReadGraph graph) throws DatabaseException {
 202         CompilationContext context = getCompilationContext(graph);
 203         return eval(prepareEvaluator(graph, context, getExpectedType(graph, context)), graph);
 204     }
 205
 206     protected static Expression getProperty(Environment environment, Expression variable, String propertyName, Type type) {
 207         return new EApply(
 208                 new EConstant(environment.getValue(FROM_DYNAMIC), type),
 209                 new EApply(
 210                         new EConstant(environment.getValue(PROPERTY_VALUE), Types.DYNAMIC),
 211                         variable,
 212                         new ELiteral(new StringConstant(propertyName))));
 213     }
 214
 215     protected static Expression getPropertyFlexible(Environment environment, Expression variable, String propertyName, Type type) {
 216         return makeTypeFlexible(environment, getProperty(environment, variable, propertyName, type), type);
 217     }
 218
 219     protected static Expression makeTypeFlexible(Environment environment, Expression base, Type originalType) {
 220         if(originalType.equals(Types.DOUBLE))
 221             return new EApply(
 222                     new EConstant(environment.getValue(FROM_DOUBLE)),
 223                     base);
 224         else if(originalType.equals(Types.FLOAT))
 225             return new EApply(
 226                     new EConstant(environment.getValue(FROM_DOUBLE)),
 227                     new EApply(
 228                             new EConstant(environment.getValue(TO_DOUBLE), Types.FLOAT),
 229                             base));
 230         else
 231             return base;
 232     }
 233
 234     protected static String resolveExpectedValueType(ReadGraph graph, Resource predicate) throws DatabaseException {
 235         Layer0 L0 = Layer0.getInstance(graph);
 236         return graph.getPossibleRelatedValue(predicate, L0.RequiresValueType, Bindings.STRING);
 237     }
 238
 239 }