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