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

Example 21 with Expression

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

the class AbstractInlineUdfsVisitor method visit.

@Override
public Boolean visit(QuantifiedExpression qe, List<FunctionDecl> arg) throws CompilationException {
    boolean changed = false;
    for (QuantifiedPair t : qe.getQuantifiedList()) {
        Pair<Boolean, Expression> p = inlineUdfsInExpr(t.getExpr(), arg);
        t.setExpr(p.second);
        if (p.first) {
            changed = true;
        }
    }
    Pair<Boolean, Expression> p2 = inlineUdfsInExpr(qe.getSatisfiesExpr(), arg);
    qe.setSatisfiesExpr(p2.second);
    return changed || p2.first;
}

Example 22 with Expression

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

the class AbstractInlineUdfsVisitor method inlineUdfsInExpr.

protected Pair<Boolean, Expression> inlineUdfsInExpr(Expression expr, List<FunctionDecl> arg) throws CompilationException {
    if (expr.getKind() != Kind.CALL_EXPRESSION) {
        boolean r = expr.accept(this, arg);
        return new Pair<>(r, expr);
    }
    CallExpr f = (CallExpr) expr;
    boolean r = expr.accept(this, arg);
    FunctionDecl implem = findFuncDeclaration(f.getFunctionSignature(), arg);
    if (implem == null) {
        return new Pair<>(r, expr);
    } else {
        // Rewrite the function body itself (without setting unbounded variables to dataset access).
        // TODO(buyingyi): throw an exception for recursive function definition or limit the stack depth.
        implem.setFuncBody(rewriteFunctionBody(implem.getFuncBody()));
        // it's one of the functions we want to inline
        List<LetClause> clauses = new ArrayList<>();
        Iterator<VarIdentifier> paramIter = implem.getParamList().iterator();
        VariableSubstitutionEnvironment subts = new VariableSubstitutionEnvironment();
        for (Expression e : f.getExprList()) {
            VarIdentifier param = paramIter.next();
            // variable inlining to take care of this.
            if (e.getKind() == Kind.VARIABLE_EXPRESSION) {
                subts.addSubstituion(new VariableExpr(param), e);
            } else {
                VarIdentifier newV = context.newVariable();
                Pair<ILangExpression, VariableSubstitutionEnvironment> p1 = e.accept(cloneVisitor, new VariableSubstitutionEnvironment());
                LetClause c = new LetClause(new VariableExpr(newV), (Expression) p1.first);
                clauses.add(c);
                subts.addSubstituion(new VariableExpr(param), new VariableExpr(newV));
            }
        }
        Pair<ILangExpression, VariableSubstitutionEnvironment> p2 = implem.getFuncBody().accept(cloneVisitor, subts);
        Expression resExpr;
        if (clauses.isEmpty()) {
            resExpr = (Expression) p2.first;
        } else {
            resExpr = generateQueryExpression(clauses, (Expression) p2.first);
        }
        return new Pair<>(true, resExpr);
    }
}

Example 23 with Expression

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

the class ClauseComparator method visit.

@Override
public Void visit(Query q, Integer step) throws CompilationException {
    Expression expr = q.getBody();
    if (expr != null) {
        if (expr.getKind() != Kind.FLWOGR_EXPRESSION) {
            out.print("select element ");
            expr.accept(this, step + 2);
        } else {
            expr.accept(this, step);
        }
    }
    if (q.isTopLevel()) {
        out.println(SEMICOLON);
    }
    return null;
}

Example 24 with Expression

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

the class ClauseComparator method visit.

@Override
public Void visit(FLWOGRExpression flwor, Integer step) throws CompilationException {
    if (step != 0) {
        out.println("(");
    }
    List<Clause> clauseList = new ArrayList<Clause>();
    clauseList.addAll(flwor.getClauseList());
    // Processes data-independent let clauses.
    if (hasFor(clauseList)) {
        processLeadingLetClauses(step, clauseList);
    }
    // Distill unnecessary order-bys before a group-by.
    distillRedundantOrderby(clauseList);
    // Correlated "for" clauses after group-by.
    Pair<GroupbyClause, List<Clause>> extraction = extractUnnestAfterGroupby(clauseList);
    GroupbyClause cuttingGbyClause = extraction.first;
    List<Clause> unnestClauseList = extraction.second;
    Expression returnExpr = flwor.getReturnExpr();
    if (unnestClauseList.size() == 0) {
        if (hasFor(clauseList)) {
            out.print(skip(step) + "select element ");
            returnExpr.accept(this, step + 2);
            out.println();
        } else {
            // The FLOWGR only contains let-return, then inline let binding expressions into the return expression.
            Map<VariableExpr, Expression> varExprMap = extractLetBindingVariables(clauseList, cuttingGbyClause);
            returnExpr = (Expression) AQLVariableSubstitutionUtil.substituteVariable(returnExpr, varExprMap);
            returnExpr.accept(this, step);
            return null;
        }
    }
    String generated = generateVariableSymbol();
    if (unnestClauseList.size() > 0) {
        Map<VariableExpr, Expression> varExprMap = extractDefinedCollectionVariables(clauseList, cuttingGbyClause, generated);
        returnExpr = (Expression) AQLVariableSubstitutionUtil.substituteVariable(returnExpr, varExprMap);
        List<Clause> newUnnestClauses = new ArrayList<Clause>();
        for (Clause nestedCl : unnestClauseList) {
            newUnnestClauses.add((Clause) AQLVariableSubstitutionUtil.substituteVariable(nestedCl, varExprMap));
        }
        unnestClauseList = newUnnestClauses;
        out.print(skip(step) + "select element " + (hasDistinct(unnestClauseList) ? "distinct " : ""));
        returnExpr.accept(this, step + 2);
        out.println();
        out.println(skip(step) + "from");
        out.print(skip(step + 2) + "( select element " + (hasDistinct(clauseList) ? "distinct " : "") + "{");
        int index = 0;
        int size = varExprMap.size();
        for (VariableExpr var : varExprMap.keySet()) {
            out.print("\'" + var.getVar().getValue().substring(1) + "\':" + var.getVar().getValue().substring(1));
            if (++index < size) {
                out.print(COMMA);
            }
        }
        out.println("}");
    }
    reorder(clauseList);
    reorder(unnestClauseList);
    mergeConsecutiveWhereClauses(clauseList);
    mergeConsecutiveWhereClauses(unnestClauseList);
    boolean firstFor = true;
    boolean firstLet = true;
    int forStep = unnestClauseList.size() == 0 ? step : step + 3;
    int size = clauseList.size();
    // "for"s.
    for (int i = 0; i < size; ++i) {
        Clause cl = clauseList.get(i);
        if (cl.getClauseType() == ClauseType.FOR_CLAUSE) {
            boolean hasConsequentFor = false;
            if (i < size - 1) {
                Clause nextCl = clauseList.get(i + 1);
                hasConsequentFor = nextCl.getClauseType() == ClauseType.FOR_CLAUSE;
            }
            visitForClause((ForClause) cl, forStep, firstFor, hasConsequentFor);
            firstFor = false;
        } else if (cl.getClauseType() == ClauseType.LET_CLAUSE) {
            boolean hasConsequentLet = false;
            if (i < size - 1) {
                Clause nextCl = clauseList.get(i + 1);
                hasConsequentLet = nextCl.getClauseType() == ClauseType.LET_CLAUSE;
            }
            visitLetClause((LetClause) cl, forStep, firstLet, hasConsequentLet);
            firstLet = false;
        } else {
            cl.accept(this, forStep);
        }
        if (cl.getClauseType() == ClauseType.FROM_CLAUSE || cl.getClauseType() == ClauseType.GROUP_BY_CLAUSE) {
            firstLet = true;
        }
    }
    if (unnestClauseList.size() > 0) {
        out.println(skip(forStep - 1) + ") as " + generated.substring(1) + ",");
        for (Clause nestedCl : unnestClauseList) {
            if (nestedCl.getClauseType() == ClauseType.FOR_CLAUSE) {
                visitForClause((ForClause) nestedCl, step - 1, firstFor, false);
            } else {
                nestedCl.accept(this, step);
            }
        }
    }
    if (step > 0) {
        out.print(skip(step - 2) + ")");
    }
    return null;
}

Example 25 with Expression

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

the class AQLCloneAndSubstituteVariablesVisitor method visit.

@Override
public Pair<ILangExpression, VariableSubstitutionEnvironment> visit(DistinctClause dc, VariableSubstitutionEnvironment env) throws CompilationException {
    List<Expression> exprList = VariableCloneAndSubstitutionUtil.visitAndCloneExprList(dc.getDistinctByExpr(), env, this);
    DistinctClause dc2 = new DistinctClause(exprList);
    return new Pair<ILangExpression, VariableSubstitutionEnvironment>(dc2, env);
}