+package org.simantics.db.layer0.scl;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+import org.simantics.databoard.Bindings;
+import org.simantics.db.ReadGraph;
+import org.simantics.db.exception.DatabaseException;
+import org.simantics.db.exception.RuntimeDatabaseException;
+import org.simantics.db.request.Read;
+import org.simantics.layer0.Layer0;
+import org.simantics.scl.compiler.common.names.Name;
+import org.simantics.scl.compiler.constants.StringConstant;
+import org.simantics.scl.compiler.elaboration.expressions.EApply;
+import org.simantics.scl.compiler.elaboration.expressions.EConstant;
+import org.simantics.scl.compiler.elaboration.expressions.ELiteral;
+import org.simantics.scl.compiler.elaboration.expressions.ESimpleLet;
+import org.simantics.scl.compiler.elaboration.expressions.EVariable;
+import org.simantics.scl.compiler.elaboration.expressions.Expression;
+import org.simantics.scl.compiler.elaboration.expressions.Variable;
+import org.simantics.scl.compiler.environment.AbstractLocalEnvironment;
+import org.simantics.scl.compiler.environment.Environment;
+import org.simantics.scl.compiler.environment.LocalEnvironment;
+import org.simantics.scl.compiler.errors.CompilationError;
+import org.simantics.scl.compiler.runtime.RuntimeEnvironment;
+import org.simantics.scl.compiler.top.ExpressionEvaluator;
+import org.simantics.scl.compiler.top.SCLExpressionCompilationException;
+import org.simantics.scl.compiler.types.TCon;
+import org.simantics.scl.compiler.types.Type;
+import org.simantics.scl.compiler.types.Types;
+import org.simantics.scl.compiler.types.exceptions.MatchException;
+import org.simantics.scl.compiler.types.kinds.Kinds;
+import org.simantics.scl.compiler.types.util.MultiFunction;
+import org.simantics.scl.runtime.SCLContext;
+import org.simantics.scl.runtime.function.Function1;
+import org.simantics.utils.datastructures.Pair;
+
+import gnu.trove.map.hash.THashMap;
+
+/**
+ * <p>This is a base implementation for compiling expressions stored into
+ * graph. It provides a skeleton and a set of methods that must be
+ * implemented to get a concrete compilation request.
+ *
+ * <p>The request returns an SCL function with type {@code EvaluationContext -> Result}
+ * where {@code EvaluationContext} is the type given by {@link #getContextVariableType()}
+ * and {@code Result} is the type of the expression that can be optionally restricted
+ * by {@link #getExpectedType(ReadGraph, AbstractExpressionCompilationContext)}.
+ *
+ * <p>Compilation calls {@link #getCompilationContext(ReadGraph)} to read all information
+ * that is needed about the context of the resource during compilation. The result must
+ * extend the type {@link AbstractExpressionCompilationContext} including at least information about
+ * {@link RuntimeEnvironment}.
+ *
+ * <p>Compilation calls {@link #getVariableAccessExpression(ReadGraph, AbstractExpressionCompilationContext, Variable, String)}
+ * to get access to local environment. The method may return null if the variable is not defined.
+ *
+ * @author Hannu Niemistö
+ *
+ * @param <Context>
+ */
+public abstract class AbstractExpressionAnalysisRequest<CompilationContext extends AbstractExpressionCompilationContext,EvaluationContext>
+implements Read<ExpressionAnalysis<EvaluationContext>> {
+
+ protected static final Type RESOURCE = Types.con("Simantics/DB", "Resource");
+ protected static final Type VARIABLE = Types.con("Simantics/Variables", "Variable");
+ protected static Name PROPERTY_VALUE = Name.create("Simantics/Variables", "propertyValue");
+ protected static Name VARIABLE_PARENT = Name.create("Simantics/Variables", "variableParent");
+ protected static Name FROM_DOUBLE = Name.create("Prelude", "fromDouble");
+ protected static Name TO_DOUBLE = Name.create("Prelude", "toDouble");
+ protected static Name FROM_DYNAMIC = Name.create("Prelude", "fromDynamic");
+
+ private static final Type DEFAULT_EXPECTED_EFFECT = Types.union(new Type[] {Types.PROC, Types.READ_GRAPH});
+
+ /**
+ * Returns the expression that will be compiled in textual form.
+ */
+ protected abstract String getExpressionText(ReadGraph graph) throws DatabaseException;
+ /**
+ * Returns the context that is used for the compilation of the expression. The context
+ * contains information about available constants and variables.
+ */
+ protected abstract CompilationContext getCompilationContext(ReadGraph graph) throws DatabaseException;
+ /**
+ * This should return the SCL type corresponding to generic type parameter {@code EvaluationContext}.
+ */
+ protected abstract Type getContextVariableType();
+ /**
+ * Returns <code>null</code>, if variable {@code name} is not defined.
+ */
+ protected abstract Expression getVariableAccessExpression(ReadGraph graph,
+ CompilationContext context, Variable contextVariable, String name) throws DatabaseException;
+
+ protected Type getExpectedType(ReadGraph graph, CompilationContext context) throws DatabaseException {
+ return Types.metaVar(Kinds.STAR);
+ }
+
+ protected Type getExpectedEffect(ReadGraph graph, CompilationContext context) throws DatabaseException {
+ return DEFAULT_EXPECTED_EFFECT;
+ }
+
+ private ExpressionEvaluator prepareEvaluator(final ReadGraph graph, final CompilationContext context, Type expectedType) throws DatabaseException {
+ final Variable contextVariable = new Variable("context", getContextVariableType());
+ LocalEnvironment localEnvironment = new AbstractLocalEnvironment() {
+ THashMap<String,Pair<Variable,Expression>> precalculatedVariables = new THashMap<String,Pair<Variable,Expression>>();
+ @Override
+ public Expression resolve(Environment environment, String localName) {
+ Pair<Variable,Expression> precalculatedVariable = precalculatedVariables.get(localName);
+ if(precalculatedVariable == null) {
+ try {
+ Expression value = getVariableAccessExpression(graph, context, contextVariable, localName);
+ if(value == null)
+ return null;
+ Variable variable = new Variable(localName);
+ precalculatedVariable = Pair.make(variable, value);
+ precalculatedVariables.put(localName, precalculatedVariable);
+ } catch (DatabaseException e) {
+ throw new RuntimeDatabaseException(e);
+ }
+ }
+ return new EVariable(precalculatedVariable.first);
+ }
+ @Override
+ public Expression preDecorateExpression(Expression expression) {
+ for(Pair<Variable,Expression> precalculatedVariable : precalculatedVariables.values())
+ expression = new ESimpleLet(precalculatedVariable.first, precalculatedVariable.second, expression);
+ return expression;
+ }
+ @Override
+ protected Variable[] getContextVariables() {
+ return new Variable[] { contextVariable };
+ }
+ };
+
+ String expressionText = getExpressionText(graph);
+ return new ExpressionEvaluator(context.runtimeEnvironment, expressionText)
+ .localEnvironment(localEnvironment)
+ .expectedType(expectedType)
+ .parseAsBlock(parseAsBlock());
+ }
+
+ protected boolean parseAsBlock() {
+ return false;
+ }
+
+ private Function1<EvaluationContext, Object> eval(ExpressionEvaluator evaluator, ReadGraph graph) throws DatabaseException {
+ Object oldGraph = SCLContext.getCurrent().put("graph", graph);
+ try {
+ return (Function1<EvaluationContext,Object>)evaluator.eval();
+ } catch(RuntimeDatabaseException e) {
+ e.printStackTrace();
+ if(e.getCause() instanceof DatabaseException)
+ throw (DatabaseException)e.getCause();
+ else
+ throw e;
+ } catch (SCLExpressionCompilationException e) {
+ StringBuilder b = new StringBuilder();
+ b.append("Couldn't compile '");
+ b.append(evaluator.getExpressionText());
+ b.append("':\n");
+ StringBuilder b2 = new StringBuilder();
+ for(CompilationError error : e.getErrors()) {
+ b2.append(error.description);
+ b2.append('\n');
+ }
+ System.err.println(b.toString() + b2.toString());
+ throw new SCLDatabaseException(b.toString()+b2.toString(), b2.toString(), e.getErrors());
+ } catch(Throwable e) {
+ // Should not happen!
+ e.printStackTrace();
+ throw new RuntimeException(e);
+ } finally {
+ SCLContext.getCurrent().put("graph", oldGraph);
+ }
+ }
+
+ public List<TCon> getExpressionEffects(final ReadGraph graph) throws DatabaseException {
+ CompilationContext context = getCompilationContext(graph);
+ Type type = Types.metaVar(Kinds.STAR);
+ eval(prepareEvaluator(graph, context, type), graph);
+
+ try {
+ MultiFunction mfun = Types.matchFunction(type, 1);
+ ArrayList<TCon> concreteEffects = new ArrayList<TCon>();
+ mfun.effect.collectConcreteEffects(concreteEffects);
+ return concreteEffects;
+ } catch(MatchException e) {
+ // Should not happen!
+ e.printStackTrace();
+ throw new RuntimeException(e);
+ }
+ }
+
+ @SuppressWarnings("unchecked")
+ @Override
+ public ExpressionAnalysis<EvaluationContext> perform(final ReadGraph graph) throws DatabaseException {
+ CompilationContext context = getCompilationContext(graph);
+ Function1<EvaluationContext,Object> fn = eval(prepareEvaluator(graph, context, getExpectedType(graph, context)), graph);
+ return getAnalysis(context, fn);
+ }
+
+ protected ExpressionAnalysis<EvaluationContext> getAnalysis(CompilationContext context, Function1<EvaluationContext,Object> fn) {
+ return new ExpressionAnalysis(fn, Collections.emptySet());
+ }
+
+ protected static Expression getProperty(Environment environment, Expression variable, String propertyName, Type type) {
+ return new EApply(
+ new EConstant(environment.getValue(FROM_DYNAMIC), type),
+ new EApply(
+ new EConstant(environment.getValue(PROPERTY_VALUE), Types.DYNAMIC),
+ variable,
+ new ELiteral(new StringConstant(propertyName))));
+ }
+
+ protected static Expression getPropertyFlexible(Environment environment, Expression variable, String propertyName, Type type) {
+ return makeTypeFlexible(environment, getProperty(environment, variable, propertyName, type), type);
+ }
+
+ protected static Expression makeTypeFlexible(Environment environment, Expression base, Type originalType) {
+ if(originalType.equals(Types.DOUBLE))
+ return new EApply(
+ new EConstant(environment.getValue(FROM_DOUBLE)),
+ base);
+ else if(originalType.equals(Types.FLOAT))
+ return new EApply(
+ new EConstant(environment.getValue(FROM_DOUBLE)),
+ new EApply(
+ new EConstant(environment.getValue(TO_DOUBLE), Types.FLOAT),
+ base));
+ else
+ return base;
+ }
+
+ protected static String resolveExpectedValueType(ReadGraph graph, org.simantics.db.layer0.variable.Variable context) throws DatabaseException {
+ Layer0 L0 = Layer0.getInstance(graph);
+ String valueType = graph.getPossibleRelatedValue(context.getPredicateResource(graph), L0.RequiresValueType, Bindings.STRING);
+ return valueType;
+ }
+}