Examples with VariableSubstitutionEnvironment org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment used on opensource projects

Example 1 with VariableSubstitutionEnvironment

use of org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment in project asterixdb by apache.

the class AQLVariableSubstitutionUtil method substituteVariable.

public static ILangExpression substituteVariable(ILangExpression expression, Map<VariableExpr, Expression> varExprMap) throws CompilationException {
    AQLCloneAndSubstituteVariablesVisitor visitor = new AQLCloneAndSubstituteVariablesVisitor(new LangRewritingContext(0));
    VariableSubstitutionEnvironment env = new VariableSubstitutionEnvironment(varExprMap);
    return expression.accept(visitor, env).first;
}

Example 2 with VariableSubstitutionEnvironment

use of org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment in project asterixdb by apache.

the class SqlppCloneAndSubstituteVariablesVisitor method visit.

@Override
public Pair<ILangExpression, VariableSubstitutionEnvironment> visit(NestClause nestClause, VariableSubstitutionEnvironment env) throws CompilationException {
    VariableExpr rightVar = nestClause.getRightVariable();
    VariableExpr newRightVar = generateNewVariable(context, rightVar);
    VariableExpr newRightPosVar = nestClause.hasPositionalVariable() ? generateNewVariable(context, nestClause.getPositionalVariable()) : null;
    // Visits the right expression.
    Expression rightExpr = (Expression) nestClause.getRightExpression().accept(this, env).first;
    // Visits the condition.
    VariableSubstitutionEnvironment currentEnv = new VariableSubstitutionEnvironment(env);
    currentEnv.removeSubstitution(newRightVar);
    if (newRightPosVar != null) {
        currentEnv.removeSubstitution(newRightPosVar);
    }
    // The condition can refer to the newRightVar and newRightPosVar.
    Expression conditionExpr = (Expression) nestClause.getConditionExpression().accept(this, currentEnv).first;
    NestClause newJoinClause = new NestClause(nestClause.getJoinType(), rightExpr, newRightVar, newRightPosVar, conditionExpr);
    return new Pair<>(newJoinClause, currentEnv);
}

Example 3 with VariableSubstitutionEnvironment

use of org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment in project asterixdb by apache.

the class SqlppCloneAndSubstituteVariablesVisitor method visit.

@Override
public Pair<ILangExpression, VariableSubstitutionEnvironment> visit(FromClause fromClause, VariableSubstitutionEnvironment env) throws CompilationException {
    VariableSubstitutionEnvironment currentEnv = new VariableSubstitutionEnvironment(env);
    List<FromTerm> newFromTerms = new ArrayList<>();
    for (FromTerm fromTerm : fromClause.getFromTerms()) {
        Pair<ILangExpression, VariableSubstitutionEnvironment> p = fromTerm.accept(this, currentEnv);
        newFromTerms.add((FromTerm) p.first);
        // A right from term could be correlated from a left from term,
        // therefore we propagate the substitution environment.
        currentEnv = p.second;
    }
    return new Pair<>(new FromClause(newFromTerms), currentEnv);
}

Example 4 with VariableSubstitutionEnvironment

use of org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment in project asterixdb by apache.

the class SqlppCloneAndSubstituteVariablesVisitor method visit.

@Override
public Pair<ILangExpression, VariableSubstitutionEnvironment> visit(FromTerm fromTerm, VariableSubstitutionEnvironment env) throws CompilationException {
    VariableExpr leftVar = fromTerm.getLeftVariable();
    VariableExpr newLeftVar = generateNewVariable(context, leftVar);
    VariableExpr newLeftPosVar = fromTerm.hasPositionalVariable() ? generateNewVariable(context, fromTerm.getPositionalVariable()) : null;
    Expression newLeftExpr = (Expression) visitUnnesBindingExpression(fromTerm.getLeftExpression(), env).first;
    List<AbstractBinaryCorrelateClause> newCorrelateClauses = new ArrayList<>();
    VariableSubstitutionEnvironment currentEnv = new VariableSubstitutionEnvironment(env);
    currentEnv.removeSubstitution(newLeftVar);
    if (newLeftPosVar != null) {
        currentEnv.removeSubstitution(newLeftPosVar);
    }
    for (AbstractBinaryCorrelateClause correlateClause : fromTerm.getCorrelateClauses()) {
        if (correlateClause.getClauseType() == ClauseType.UNNEST_CLAUSE) {
            // The right-hand-side of unnest could be correlated with the left side,
            // therefore we propagate the substitution environment of the left-side.
            Pair<ILangExpression, VariableSubstitutionEnvironment> p = correlateClause.accept(this, currentEnv);
            currentEnv = p.second;
            newCorrelateClauses.add((AbstractBinaryCorrelateClause) p.first);
        } else {
            // The right-hand-side of join and nest could not be correlated with the left side,
            // therefore we propagate the original substitution environment.
            newCorrelateClauses.add((AbstractBinaryCorrelateClause) correlateClause.accept(this, env).first);
            // Join binding variables should be removed for further traversal.
            currentEnv.removeSubstitution(correlateClause.getRightVariable());
            if (correlateClause.hasPositionalVariable()) {
                currentEnv.removeSubstitution(correlateClause.getPositionalVariable());
            }
        }
    }
    return new Pair<>(new FromTerm(newLeftExpr, newLeftVar, newLeftPosVar, newCorrelateClauses), currentEnv);
}

Example 5 with VariableSubstitutionEnvironment

use of org.apache.asterix.lang.common.rewrites.VariableSubstitutionEnvironment in project asterixdb by apache.

the class SqlppCloneAndSubstituteVariablesVisitor method visit.

@Override
public Pair<ILangExpression, VariableSubstitutionEnvironment> visit(UnnestClause unnestClause, VariableSubstitutionEnvironment env) throws CompilationException {
    VariableExpr rightVar = unnestClause.getRightVariable();
    VariableExpr newRightVar = generateNewVariable(context, rightVar);
    VariableExpr newRightPosVar = unnestClause.hasPositionalVariable() ? generateNewVariable(context, unnestClause.getPositionalVariable()) : null;
    // Visits the right expression.
    Expression rightExpr = (Expression) visitUnnesBindingExpression(unnestClause.getRightExpression(), env).first;
    // Visits the condition.
    VariableSubstitutionEnvironment currentEnv = new VariableSubstitutionEnvironment(env);
    currentEnv.removeSubstitution(newRightVar);
    if (newRightPosVar != null) {
        currentEnv.removeSubstitution(newRightPosVar);
    }
    // The condition can refer to the newRightVar and newRightPosVar.
    UnnestClause newJoinClause = new UnnestClause(unnestClause.getJoinType(), rightExpr, newRightVar, newRightPosVar);
    return new Pair<>(newJoinClause, currentEnv);
}