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