Examples with Expression org.apache.asterix.lang.common.base.Expression used on opensource projects

Example 6 with Expression

use of org.apache.asterix.lang.common.base.Expression in project asterixdb by apache.

the class SqlppExpressionToPlanTranslator method processSelectClause.

// Generates the return expression for a select clause.
private Pair<ILogicalOperator, LogicalVariable> processSelectClause(SelectBlock selectBlock, Mutable<ILogicalOperator> tupSrc) throws CompilationException {
    SelectClause selectClause = selectBlock.getSelectClause();
    Expression returnExpr;
    if (selectClause.selectElement()) {
        returnExpr = selectClause.getSelectElement().getExpression();
    } else {
        returnExpr = generateReturnExpr(selectClause, selectBlock);
    }
    Pair<ILogicalExpression, Mutable<ILogicalOperator>> eo = langExprToAlgExpression(returnExpr, tupSrc);
    LogicalVariable returnVar;
    ILogicalOperator returnOperator;
    if (returnExpr.getKind() == Kind.VARIABLE_EXPRESSION) {
        VariableExpr varExpr = (VariableExpr) returnExpr;
        returnOperator = eo.second.getValue();
        returnVar = context.getVar(varExpr.getVar().getId());
    } else {
        returnVar = context.newVar();
        returnOperator = new AssignOperator(returnVar, new MutableObject<ILogicalExpression>(eo.first));
        returnOperator.getInputs().add(eo.second);
    }
    if (selectClause.distinct()) {
        DistinctOperator distinctOperator = new DistinctOperator(mkSingletonArrayList(new MutableObject<ILogicalExpression>(new VariableReferenceExpression(returnVar))));
        distinctOperator.getInputs().add(new MutableObject<ILogicalOperator>(returnOperator));
        return new Pair<>(distinctOperator, returnVar);
    } else {
        return new Pair<>(returnOperator, returnVar);
    }
}

Example 7 with Expression

use of org.apache.asterix.lang.common.base.Expression in project asterixdb by apache.

the class SqlppExpressionToPlanTranslator method visit.

@Override
public Pair<ILogicalOperator, LogicalVariable> visit(Query q, Mutable<ILogicalOperator> tupSource) throws CompilationException {
    Expression queryBody = q.getBody();
    if (queryBody.getKind() == Kind.SELECT_EXPRESSION) {
        SelectExpression selectExpr = (SelectExpression) queryBody;
        if (q.isTopLevel()) {
            selectExpr.setSubquery(false);
        }
        return queryBody.accept(this, tupSource);
    } else {
        LogicalVariable var = context.newVar();
        Pair<ILogicalExpression, Mutable<ILogicalOperator>> eo = langExprToAlgExpression(queryBody, tupSource);
        AssignOperator assignOp = new AssignOperator(var, new MutableObject<ILogicalExpression>(eo.first));
        assignOp.getInputs().add(eo.second);
        ProjectOperator projectOp = new ProjectOperator(var);
        projectOp.getInputs().add(new MutableObject<ILogicalOperator>(assignOp));
        return new Pair<>(projectOp, var);
    }
}

Example 8 with Expression

use of org.apache.asterix.lang.common.base.Expression in project asterixdb by apache.

the class SqlppExpressionToPlanTranslator method visit.

@Override
public Pair<ILogicalOperator, LogicalVariable> visit(FromTerm fromTerm, Mutable<ILogicalOperator> tupSource) throws CompilationException {
    LogicalVariable fromVar = context.newVarFromExpression(fromTerm.getLeftVariable());
    Expression fromExpr = fromTerm.getLeftExpression();
    Pair<ILogicalExpression, Mutable<ILogicalOperator>> eo = langExprToAlgExpression(fromExpr, tupSource);
    ILogicalOperator unnestOp;
    if (fromTerm.hasPositionalVariable()) {
        LogicalVariable pVar = context.newVarFromExpression(fromTerm.getPositionalVariable());
        // We set the positional variable type as BIGINT type.
        unnestOp = new UnnestOperator(fromVar, new MutableObject<ILogicalExpression>(makeUnnestExpression(eo.first)), pVar, BuiltinType.AINT64, new PositionWriter());
    } else {
        unnestOp = new UnnestOperator(fromVar, new MutableObject<ILogicalExpression>(makeUnnestExpression(eo.first)));
    }
    unnestOp.getInputs().add(eo.second);
    // Processes joins, unnests, and nests.
    Mutable<ILogicalOperator> topOpRef = new MutableObject<>(unnestOp);
    if (fromTerm.hasCorrelateClauses()) {
        for (AbstractBinaryCorrelateClause correlateClause : fromTerm.getCorrelateClauses()) {
            if (correlateClause.getClauseType() == ClauseType.UNNEST_CLAUSE) {
                // Correlation is allowed.
                topOpRef = new MutableObject<>(correlateClause.accept(this, topOpRef).first);
            } else {
                // Correlation is dis-allowed.
                uncorrelatedLeftBranchStack.push(topOpRef);
                topOpRef = new MutableObject<>(correlateClause.accept(this, tupSource).first);
            }
        }
    }
    return new Pair<>(topOpRef.getValue(), fromVar);
}

Example 9 with Expression

use of org.apache.asterix.lang.common.base.Expression in project asterixdb by apache.

the class SqlppGroupBySugarVisitor method wrapAggregationArgument.

private Expression wrapAggregationArgument(Expression argExpr) throws CompilationException {
    Expression expr = argExpr;
    Set<VariableExpr> freeVars = SqlppRewriteUtil.getFreeVariable(expr);
    VariableExpr fromBindingVar = new VariableExpr(context.newVariable());
    FromTerm fromTerm = new FromTerm(groupVar, fromBindingVar, null, null);
    FromClause fromClause = new FromClause(Collections.singletonList(fromTerm));
    // Maps field variable expressions to field accesses.
    Map<Expression, Expression> varExprMap = new HashMap<>();
    for (VariableExpr usedVar : freeVars) {
        // Reference to a field in the group variable.
        if (fieldVars.contains(usedVar)) {
            // Rewrites to a reference to a field in the group variable.
            varExprMap.put(usedVar, new FieldAccessor(fromBindingVar, SqlppVariableUtil.toUserDefinedVariableName(usedVar.getVar())));
        }
    }
    // Select clause.
    SelectElement selectElement = new SelectElement(SqlppRewriteUtil.substituteExpression(expr, varExprMap, context));
    SelectClause selectClause = new SelectClause(selectElement, null, false);
    // Construct the select expression.
    SelectBlock selectBlock = new SelectBlock(selectClause, fromClause, null, null, null, null, null);
    SelectSetOperation selectSetOperation = new SelectSetOperation(new SetOperationInput(selectBlock, null), null);
    return new SelectExpression(null, selectSetOperation, null, null, true);
}

Example 10 with Expression

use of org.apache.asterix.lang.common.base.Expression in project asterixdb by apache.

the class SqlppGroupByVisitor method visit.

@Override
public Expression visit(GroupbyClause gc, ILangExpression arg) throws CompilationException {
    // Puts all FROM binding variables into withVarList.
    FromClause fromClause = (FromClause) arg;
    Collection<VariableExpr> fromBindingVars = fromClause == null ? new ArrayList<>() : SqlppVariableUtil.getBindingVariables(fromClause);
    Map<Expression, VariableExpr> withVarMap = new HashMap<>();
    for (VariableExpr fromBindingVar : fromBindingVars) {
        VariableExpr varExpr = new VariableExpr();
        varExpr.setIsNewVar(false);
        varExpr.setVar(fromBindingVar.getVar());
        VariableExpr newVarExpr = (VariableExpr) SqlppRewriteUtil.deepCopy(varExpr);
        withVarMap.put(varExpr, newVarExpr);
    }
    // Sets the field list for the group variable.
    List<Pair<Expression, Identifier>> groupFieldList = new ArrayList<>();
    if (!gc.hasGroupFieldList()) {
        for (VariableExpr varExpr : fromBindingVars) {
            Pair<Expression, Identifier> varIdPair = new Pair<>(new VariableExpr(varExpr.getVar()), SqlppVariableUtil.toUserDefinedVariableName(varExpr.getVar()));
            groupFieldList.add(varIdPair);
        }
        gc.setGroupFieldList(groupFieldList);
    } else {
        for (Pair<Expression, Identifier> groupField : gc.getGroupFieldList()) {
            Expression newFieldExpr = groupField.first.accept(this, arg);
            groupFieldList.add(new Pair<>(newFieldExpr, groupField.second));
            // Adds a field binding variable into withVarList.
            VariableExpr bindingVar = new VariableExpr(new VarIdentifier(SqlppVariableUtil.toInternalVariableName(groupField.second.getValue())));
            withVarMap.put(newFieldExpr, bindingVar);
        }
    }
    gc.setGroupFieldList(groupFieldList);
    // Sets the group variable.
    if (!gc.hasGroupVar()) {
        VariableExpr groupVar = new VariableExpr(context.newVariable());
        gc.setGroupVar(groupVar);
    }
    // Adds the group variable into the "with" (i.e., re-binding) variable list.
    VariableExpr gbyVarRef = new VariableExpr(gc.getGroupVar().getVar());
    gbyVarRef.setIsNewVar(false);
    withVarMap.put(gbyVarRef, (VariableExpr) SqlppRewriteUtil.deepCopy(gbyVarRef));
    gc.setWithVarMap(withVarMap);
    // Call super.visit(...) to scope variables.
    return super.visit(gc, arg);
}