Repository: microsoft/semantic-kernel
File: dotnet/src/VectorData/Redis/RedisFilterTranslator.cs (C#)

Code before:
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using Microsoft.Extensions.VectorData.ProviderServices;
using Microsoft.Extensions.VectorData.ProviderServices.Filter;

namespace Microsoft.SemanticKernel.Connectors.Redis;

internal class RedisFilterTranslator
{
    private CollectionModel _model = null!;
    private ParameterExpression _recordParameter = null!;
    private readonly StringBuilder _filter = new();

    internal string Translate(LambdaExpression lambdaExpression, CollectionModel model)
    {
        Debug.Assert(this._filter.Length == 0);

        this._model = model;

        Debug.Assert(lambdaExpression.Parameters.Count == 1);
        this._recordParameter = lambdaExpression.Parameters[0];

        // Weaviate doesn't seem to have a native way of expressing "always true" filters; since this scenario is important for fetching
        // all records (via GetAsync with filter), we special-case and support it here. Note that false isn't supported (useless),
        // nor is 'x && true'.
        if (lambdaExpression.Body is ConstantExpression { Value: true })
        {
            return "*";
        }

        var preprocessor = new FilterTranslationPreprocessor { SupportsParameterization = false };
        var preprocessedExpression = preprocessor.Preprocess(lambdaExpression.Body);

        this.Translate(preprocessedExpression);
        return this._filter.ToString();
    }

    private void Translate(Expression? node)
    {
        switch (node)
        {
            case BinaryExpression
            {
                NodeType: ExpressionType.Equal or ExpressionType.NotEqual
                or ExpressionType.GreaterThan or ExpressionType.GreaterThanOrEqual
                or ExpressionType.LessThan or ExpressionType.LessThanOrEqual
            } binary:
                this.TranslateEqualityComparison(binary);

Review comment (suggestion):
```suggestion
        // Redis doesn't seem to have a native way of expressing "always true" filters; since this scenario is important for fetching
```

Code after:
using System.Diagnostics;
using System.Diagnostics.CodeAnalysis;
using System.Linq;
using System.Linq.Expressions;
using System.Text;
using Microsoft.Extensions.VectorData.ProviderServices;
using Microsoft.Extensions.VectorData.ProviderServices.Filter;

namespace Microsoft.SemanticKernel.Connectors.Redis;

internal class RedisFilterTranslator
{
    private CollectionModel _model = null!;
    private ParameterExpression _recordParameter = null!;
    private readonly StringBuilder _filter = new();

    internal string Translate(LambdaExpression lambdaExpression, CollectionModel model)
    {
        Debug.Assert(this._filter.Length == 0);

        this._model = model;

        Debug.Assert(lambdaExpression.Parameters.Count == 1);
        this._recordParameter = lambdaExpression.Parameters[0];

        // Redis doesn't seem to have a native way of expressing "always true" filters; since this scenario is important for fetching
        // all records (via GetAsync with filter), we special-case and support it here. Note that false isn't supported (useless),
        // nor is 'x && true'.
        if (lambdaExpression.Body is ConstantExpression { Value: true })
        {
            return "*";
        }

        var preprocessor = new FilterTranslationPreprocessor { SupportsParameterization = false };
        var preprocessedExpression = preprocessor.Preprocess(lambdaExpression.Body);

        this.Translate(preprocessedExpression);
        return this._filter.ToString();
    }

    private void Translate(Expression? node)
    {
        switch (node)
        {
            case BinaryExpression
            {
                NodeType: ExpressionType.Equal or ExpressionType.NotEqual
                or ExpressionType.GreaterThan or ExpressionType.GreaterThanOrEqual
                or ExpressionType.LessThan or ExpressionType.LessThanOrEqual
            } binary:
                this.TranslateEqualityComparison(binary);