lbug 0.16.1

An in-process property graph database management system built for query speed and scalability
Documentation 
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#include "binder/binder.h"
#include "binder/expression/aggregate_function_expression.h"
#include "binder/expression/scalar_function_expression.h"
#include "binder/expression_binder.h"
#include "catalog/catalog.h"
#include "common/exception/binder.h"
#include "function/built_in_function_utils.h"
#include "function/cast/vector_cast_functions.h"
#include "function/rewrite_function.h"
#include "function/scalar_macro_function.h"
#include "parser/expression/parsed_expression_visitor.h"
#include "parser/expression/parsed_function_expression.h"
#include "transaction/transaction.h"
#include <format>

using namespace lbug::common;
using namespace lbug::parser;
using namespace lbug::function;
using namespace lbug::catalog;

namespace lbug {
namespace binder {

std::shared_ptr<Expression> ExpressionBinder::bindFunctionExpression(const ParsedExpression& expr) {
    auto funcExpr = expr.constPtrCast<ParsedFunctionExpression>();
    auto functionName = funcExpr->getNormalizedFunctionName();
    auto transaction = transaction::Transaction::Get(*context);
    auto catalog = Catalog::Get(*context);
    auto entry = catalog->getFunctionEntry(transaction, functionName);
    switch (entry->getType()) {
    case CatalogEntryType::SCALAR_FUNCTION_ENTRY:
        return bindScalarFunctionExpression(expr, functionName);
    case CatalogEntryType::REWRITE_FUNCTION_ENTRY:
        return bindRewriteFunctionExpression(expr);
    case CatalogEntryType::AGGREGATE_FUNCTION_ENTRY:
        return bindAggregateFunctionExpression(expr, functionName, funcExpr->getIsDistinct());
    case CatalogEntryType::SCALAR_MACRO_ENTRY:
        return bindMacroExpression(expr, functionName);
    default:
        throw BinderException(
            std::format("{} is a {}. Scalar function, aggregate function or macro was expected. ",
                functionName, CatalogEntryTypeUtils::toString(entry->getType())));
    }
}

std::shared_ptr<Expression> ExpressionBinder::bindScalarFunctionExpression(
    const ParsedExpression& parsedExpression, const std::string& functionName) {
    expression_vector children;
    for (auto i = 0u; i < parsedExpression.getNumChildren(); ++i) {
        auto expr = bindExpression(*parsedExpression.getChild(i));
        if (parsedExpression.getChild(i)->hasAlias()) {
            expr->setAlias(parsedExpression.getChild(i)->getAlias());
        }
        children.push_back(expr);
    }
    return bindScalarFunctionExpression(children, functionName,
        parsedExpression.constCast<ParsedFunctionExpression>().getOptionalArguments());
}

static std::vector<LogicalType> getTypes(const expression_vector& exprs) {
    std::vector<LogicalType> result;
    for (auto& expr : exprs) {
        result.push_back(expr->getDataType().copy());
    }
    return result;
}

std::shared_ptr<Expression> ExpressionBinder::bindScalarFunctionExpression(
    const expression_vector& children, const std::string& functionName,
    std::vector<std::string> optionalArguments) {
    auto catalog = Catalog::Get(*context);
    auto transaction = transaction::Transaction::Get(*context);
    auto childrenTypes = getTypes(children);

    auto entry = catalog->getFunctionEntry(transaction, functionName);

    auto function = BuiltInFunctionsUtils::matchFunction(functionName, childrenTypes,
        entry->ptrCast<FunctionCatalogEntry>())
                        ->ptrCast<ScalarFunction>()
                        ->copy();
    if (children.size() == 2 && children[1]->expressionType == ExpressionType::LAMBDA) {
        if (!function->isListLambda) {
            throw BinderException(std::format("{} does not support lambda input.", functionName));
        }
        bindLambdaExpression(*children[0], *children[1]);
    }
    expression_vector childrenAfterCast;
    std::unique_ptr<FunctionBindData> bindData;
    auto bindInput =
        ScalarBindFuncInput{children, function.get(), context, std::move(optionalArguments)};
    if (functionName == CastAnyFunction::name) {
        bindData = function->bindFunc(bindInput);
        if (bindData == nullptr) { // No need to cast.
            // TODO(Xiyang): We should return a deep copy otherwise the same expression might
            // appear in the final projection list repeatedly.
            // E.g. RETURN cast([NULL], "INT64[1][]"), cast([NULL], "INT64[1][][]")
            return children[0];
        }
        auto childAfterCast = children[0];
        if (children[0]->getDataType().getLogicalTypeID() == LogicalTypeID::ANY) {
            childAfterCast = implicitCastIfNecessary(children[0], LogicalType::STRING());
        }
        childrenAfterCast.push_back(std::move(childAfterCast));
    } else {
        if (function->bindFunc) {
            bindData = function->bindFunc(bindInput);
        } else {
            bindData = std::make_unique<FunctionBindData>(LogicalType(function->returnTypeID));
        }
        if (!bindData->paramTypes.empty()) {
            for (auto i = 0u; i < children.size(); ++i) {
                childrenAfterCast.push_back(
                    implicitCastIfNecessary(children[i], bindData->paramTypes[i]));
            }
        } else {
            for (auto i = 0u; i < children.size(); ++i) {
                auto id = function->isVarLength ? function->parameterTypeIDs[0] :
                                                  function->parameterTypeIDs[i];
                auto type = LogicalType(id);
                childrenAfterCast.push_back(implicitCastIfNecessary(children[i], type));
            }
        }
    }
    auto uniqueExpressionName =
        ScalarFunctionExpression::getUniqueName(function->name, childrenAfterCast);
    return std::make_shared<ScalarFunctionExpression>(ExpressionType::FUNCTION, std::move(function),
        std::move(bindData), std::move(childrenAfterCast), uniqueExpressionName);
}

std::shared_ptr<Expression> ExpressionBinder::bindRewriteFunctionExpression(
    const ParsedExpression& expr) {
    auto& funcExpr = expr.constCast<ParsedFunctionExpression>();
    expression_vector children;
    for (auto i = 0u; i < expr.getNumChildren(); ++i) {
        children.push_back(bindExpression(*expr.getChild(i)));
    }
    auto childrenTypes = getTypes(children);
    auto functionName = funcExpr.getNormalizedFunctionName();
    auto transaction = transaction::Transaction::Get(*context);
    auto entry = Catalog::Get(*context)->getFunctionEntry(transaction, functionName);
    auto match = BuiltInFunctionsUtils::matchFunction(functionName, childrenTypes,
        entry->ptrCast<FunctionCatalogEntry>());
    auto function = match->constPtrCast<RewriteFunction>();
    DASSERT(function->rewriteFunc != nullptr);
    auto input = RewriteFunctionBindInput(context, this, children);
    return function->rewriteFunc(input);
}

std::shared_ptr<Expression> ExpressionBinder::bindAggregateFunctionExpression(
    const ParsedExpression& parsedExpression, const std::string& functionName, bool isDistinct) {
    std::vector<LogicalType> childrenTypes;
    expression_vector children;
    for (auto i = 0u; i < parsedExpression.getNumChildren(); ++i) {
        auto child = bindExpression(*parsedExpression.getChild(i));
        childrenTypes.push_back(child->dataType.copy());
        children.push_back(std::move(child));
    }
    auto transaction = transaction::Transaction::Get(*context);
    auto entry = Catalog::Get(*context)->getFunctionEntry(transaction, functionName);
    auto function = BuiltInFunctionsUtils::matchAggregateFunction(functionName, childrenTypes,
        isDistinct, entry->ptrCast<FunctionCatalogEntry>())
                        ->copy();
    if (function.paramRewriteFunc) {
        function.paramRewriteFunc(children);
    }
    if (functionName == CollectFunction::name && parsedExpression.hasAlias() &&
        children[0]->getDataType().getLogicalTypeID() == LogicalTypeID::NODE) {
        auto& node = children[0]->constCast<NodeExpression>();
        binder->scope.memorizeTableEntries(parsedExpression.getAlias(), node.getEntries());
    }
    auto uniqueExpressionName =
        AggregateFunctionExpression::getUniqueName(function.name, children, function.isDistinct);
    if (children.empty()) {
        uniqueExpressionName = binder->getUniqueExpressionName(uniqueExpressionName);
    }
    std::unique_ptr<FunctionBindData> bindData;
    if (function.bindFunc) {
        auto bindInput = ScalarBindFuncInput{children, &function, context,
            std::vector<std::string>{} /* optionalParams */};
        bindData = function.bindFunc(bindInput);
    } else {
        bindData = std::make_unique<FunctionBindData>(LogicalType(function.returnTypeID));
    }
    return std::make_shared<AggregateFunctionExpression>(std::move(function), std::move(bindData),
        std::move(children), uniqueExpressionName);
}

std::shared_ptr<Expression> ExpressionBinder::bindMacroExpression(
    const ParsedExpression& parsedExpression, const std::string& macroName) {
    auto transaction = transaction::Transaction::Get(*context);
    auto scalarMacroFunction =
        Catalog::Get(*context)->getScalarMacroFunction(transaction, macroName);
    auto macroExpr = scalarMacroFunction->expression->copy();
    auto parameterVals = scalarMacroFunction->getDefaultParameterVals();
    auto& parsedFuncExpr = parsedExpression.constCast<ParsedFunctionExpression>();
    auto positionalArgs = scalarMacroFunction->getPositionalArgs();
    if (parsedFuncExpr.getNumChildren() > scalarMacroFunction->getNumArgs() ||
        parsedFuncExpr.getNumChildren() < positionalArgs.size()) {
        throw BinderException{"Invalid number of arguments for macro " + macroName + "."};
    }
    // Bind positional arguments.
    for (auto i = 0u; i < positionalArgs.size(); i++) {
        parameterVals[positionalArgs[i]] = parsedFuncExpr.getChild(i);
    }
    // Bind arguments with default values.
    for (auto i = positionalArgs.size(); i < parsedFuncExpr.getNumChildren(); i++) {
        auto parameterName =
            scalarMacroFunction->getDefaultParameterName(i - positionalArgs.size());
        parameterVals[parameterName] = parsedFuncExpr.getChild(i);
    }
    auto replacer = MacroParameterReplacer(parameterVals);
    return bindExpression(*replacer.replace(std::move(macroExpr)));
}

} // namespace binder
} // namespace lbug