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

Example 31 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(JoinClause joinClause, VariableSubstitutionEnvironment env) throws CompilationException {
    VariableExpr rightVar = joinClause.getRightVariable();
    VariableExpr newRightVar = generateNewVariable(context, rightVar);
    VariableExpr newRightPosVar = joinClause.hasPositionalVariable() ? generateNewVariable(context, joinClause.getPositionalVariable()) : null;
    // Visits the right expression.
    Expression newRightExpr = (Expression) visitUnnesBindingExpression(joinClause.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.
    Expression conditionExpr = (Expression) joinClause.getConditionExpression().accept(this, currentEnv).first;
    JoinClause newJoinClause = new JoinClause(joinClause.getJoinType(), newRightExpr, newRightVar, newRightPosVar, conditionExpr);
    return new Pair<>(newJoinClause, currentEnv);
}