Reusable Query Filters

This recipe shows how to define reusable filtering logic as [Expressive] properties and extension methods, and compose them across multiple queries without duplicating LINQ expressions.

The Pattern

Define your filtering criteria as [Expressive] members that return bool. Use them in Where() clauses exactly as you would any other property. EF Core translates the expanded expression to a SQL WHERE clause.

Example: Active Entity Filter

db
    .Customers
    .Where(c => c.IsActive())

// Setup
public static class CustomerActiveExt
{
    [Expressive]
    public static bool IsActive(this Customer c) =>
        c.Email != null
        && c.JoinedAt >= new DateTime(2023, 1, 1);
}

SELECT "c"."Id", "c"."Country", "c"."Email", "c"."JoinedAt", "c"."Name"
FROM "Customers" AS "c"
WHERE "c"."Email" IS NOT NULL AND "c"."JoinedAt" >= '2023-01-01 00:00:00'

// === ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt.IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Customer.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt 
    {
        // [Expressive]
        // public static bool IsActive(this Customer c) => c.Email != null && c.JoinedAt >= new DateTime(2023, 1, 1);
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool>> IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Customer_Expression() 
        {
            var p_c = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer), "c");
            var expr_2 = global::System.Linq.Expressions.Expression.Property(p_c, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("Email", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // c.Email
            var expr_4 = global::System.Linq.Expressions.Expression.Constant(null, typeof(object)); // null
            var expr_3 = global::System.Linq.Expressions.Expression.Convert(expr_4, typeof(string));
            var expr_1 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.NotEqual, expr_2, expr_3);
            var expr_6 = global::System.Linq.Expressions.Expression.Property(p_c, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("JoinedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // c.JoinedAt
            var expr_8 = global::System.Linq.Expressions.Expression.Constant(2023, typeof(int)); // 2023
            var expr_9 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_10 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_7 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), expr_8, expr_9, expr_10);
            var expr_5 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.GreaterThanOrEqual, expr_6, expr_7, false, typeof(global::System.DateTime).GetMethod("op_GreaterThanOrEqual", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_5);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool>>(expr_0, p_c);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt.Attributes.g.cs ===
// <auto-generated/>

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    static partial class ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt { }
}


// === ExpressionRegistry.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal static class ExpressionRegistry
    {
        private static Dictionary<nint, LambdaExpression> Build()
        {
            const BindingFlags allFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
            var map = new Dictionary<nint, LambdaExpression>();
            
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.CustomerActiveExt).GetMethod("IsActive", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt", "IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Customer_Expression");
            
            return map;
        }
        
        private static volatile Dictionary<nint, LambdaExpression> _map = Build();
        
        internal static void ResetMap() => _map = Build();
        
        public static LambdaExpression TryGet(MemberInfo member)
        {
            var handle = member switch
            {
                MethodInfo m      => (nint?)m.MethodHandle.Value,
                PropertyInfo p    => p.GetMethod?.MethodHandle.Value,
                ConstructorInfo c => (nint?)c.MethodHandle.Value,
                _                 => null
            };
            
            return handle.HasValue && _map.TryGetValue(handle.Value, out var expr) ? expr : null;
        }
        
        private static void Register(Dictionary<nint, LambdaExpression> map, MethodBase m, string exprClass, string exprMethodName)
        {
            if (m is null) return;
            var exprType = m.DeclaringType?.Assembly.GetType(exprClass) ?? typeof(ExpressionRegistry).Assembly.GetType(exprClass);
            var exprMethod = exprType?.GetMethod(exprMethodName, BindingFlags.Static | BindingFlags.NonPublic);
            if (exprMethod is null) return;
            var expr = (LambdaExpression)exprMethod.Invoke(null, null)!;
            
            // Apply declared transformers from the generated class (if any)
            const string expressionSuffix = "_Expression";
            if (exprMethodName.EndsWith(expressionSuffix, StringComparison.Ordinal))
            {
                var transformersSuffix = exprMethodName.Substring(0, exprMethodName.Length - expressionSuffix.Length) + "_Transformers";
                var transformersMethod = exprType.GetMethod(transformersSuffix, BindingFlags.Static | BindingFlags.NonPublic);
                if (transformersMethod?.Invoke(null, null) is global::ExpressiveSharp.IExpressionTreeTransformer[] transformers)
                {
                    Expression transformed = expr;
                    foreach (var t in transformers) transformed = t.Transform(transformed);
                    if (transformed is LambdaExpression lambdaResult) expr = lambdaResult;
                }
            }
            
            map[m.MethodHandle.Value] = expr;
        }
    }
}


// === PolyfillInterceptors_b1293e61.g.cs ===
// <auto-generated/>
#nullable disable

namespace ExpressiveSharp.Generated.Interceptors
{
    internal static partial class PolyfillInterceptors
    {
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "MPshvEF9twAvXsvy9Xe9UYIBAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer> __Polyfill_Where_3e61_14_24(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool> __func)
        {
            // Source: c => c.IsActive()
            var i3e6114c24_p_c = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer), "c");
            var i3e6114c24_expr_0 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.CustomerActiveExt).GetMethod("IsActive", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer) }, null), new global::System.Linq.Expressions.Expression[] { i3e6114c24_p_c }); // c.IsActive()
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool>>(i3e6114c24_expr_0, i3e6114c24_p_c);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer>)source,
                    __lambda));
        }
    }
}

namespace System.Runtime.CompilerServices
{
    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
    file sealed class InterceptsLocationAttribute : global::System.Attribute
    {
        public InterceptsLocationAttribute(int version, string data) { }
    }
}

Reuse everywhere:

db
    .Customers
    .Where(c => c.IsActive() && c.Country == "US")
    .Select(c => c.Id)

// Setup
public static class CustomerActiveExt2
{
    [Expressive]
    public static bool IsActive(this Customer c) =>
        c.Email != null
        && c.JoinedAt >= new DateTime(2023, 1, 1);
}

SELECT "c"."Id"
FROM "Customers" AS "c"
WHERE "c"."Email" IS NOT NULL AND "c"."JoinedAt" >= '2023-01-01 00:00:00' AND "c"."Country" = 'US'

// === ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt2.IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Customer.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt2 
    {
        // [Expressive]
        // public static bool IsActive(this Customer c) => c.Email != null && c.JoinedAt >= new DateTime(2023, 1, 1);
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool>> IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Customer_Expression() 
        {
            var p_c = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer), "c");
            var expr_2 = global::System.Linq.Expressions.Expression.Property(p_c, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("Email", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // c.Email
            var expr_4 = global::System.Linq.Expressions.Expression.Constant(null, typeof(object)); // null
            var expr_3 = global::System.Linq.Expressions.Expression.Convert(expr_4, typeof(string));
            var expr_1 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.NotEqual, expr_2, expr_3);
            var expr_6 = global::System.Linq.Expressions.Expression.Property(p_c, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("JoinedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // c.JoinedAt
            var expr_8 = global::System.Linq.Expressions.Expression.Constant(2023, typeof(int)); // 2023
            var expr_9 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_10 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_7 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), expr_8, expr_9, expr_10);
            var expr_5 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.GreaterThanOrEqual, expr_6, expr_7, false, typeof(global::System.DateTime).GetMethod("op_GreaterThanOrEqual", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_5);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool>>(expr_0, p_c);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt2.Attributes.g.cs ===
// <auto-generated/>

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    static partial class ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt2 { }
}


// === ExpressionRegistry.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal static class ExpressionRegistry
    {
        private static Dictionary<nint, LambdaExpression> Build()
        {
            const BindingFlags allFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
            var map = new Dictionary<nint, LambdaExpression>();
            
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.CustomerActiveExt2).GetMethod("IsActive", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_CustomerActiveExt2", "IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Customer_Expression");
            
            return map;
        }
        
        private static volatile Dictionary<nint, LambdaExpression> _map = Build();
        
        internal static void ResetMap() => _map = Build();
        
        public static LambdaExpression TryGet(MemberInfo member)
        {
            var handle = member switch
            {
                MethodInfo m      => (nint?)m.MethodHandle.Value,
                PropertyInfo p    => p.GetMethod?.MethodHandle.Value,
                ConstructorInfo c => (nint?)c.MethodHandle.Value,
                _                 => null
            };
            
            return handle.HasValue && _map.TryGetValue(handle.Value, out var expr) ? expr : null;
        }
        
        private static void Register(Dictionary<nint, LambdaExpression> map, MethodBase m, string exprClass, string exprMethodName)
        {
            if (m is null) return;
            var exprType = m.DeclaringType?.Assembly.GetType(exprClass) ?? typeof(ExpressionRegistry).Assembly.GetType(exprClass);
            var exprMethod = exprType?.GetMethod(exprMethodName, BindingFlags.Static | BindingFlags.NonPublic);
            if (exprMethod is null) return;
            var expr = (LambdaExpression)exprMethod.Invoke(null, null)!;
            
            // Apply declared transformers from the generated class (if any)
            const string expressionSuffix = "_Expression";
            if (exprMethodName.EndsWith(expressionSuffix, StringComparison.Ordinal))
            {
                var transformersSuffix = exprMethodName.Substring(0, exprMethodName.Length - expressionSuffix.Length) + "_Transformers";
                var transformersMethod = exprType.GetMethod(transformersSuffix, BindingFlags.Static | BindingFlags.NonPublic);
                if (transformersMethod?.Invoke(null, null) is global::ExpressiveSharp.IExpressionTreeTransformer[] transformers)
                {
                    Expression transformed = expr;
                    foreach (var t in transformers) transformed = t.Transform(transformed);
                    if (transformed is LambdaExpression lambdaResult) expr = lambdaResult;
                }
            }
            
            map[m.MethodHandle.Value] = expr;
        }
    }
}


// === PolyfillInterceptors_b1293e61.g.cs ===
// <auto-generated/>
#nullable disable

namespace ExpressiveSharp.Generated.Interceptors
{
    internal static partial class PolyfillInterceptors
    {
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "DsycSMkNdv4BbIVBoMKvNrABAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<int> __Polyfill_Select_3e61_14_70(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, int> __func)
        {
            // Source: c => c.Id
            var i3e6114c70_p_c = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer), "c");
            var i3e6114c70_expr_0 = global::System.Linq.Expressions.Expression.Property(i3e6114c70_p_c, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("Id", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // c.Id
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, int>>(i3e6114c70_expr_0, i3e6114c70_p_c);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Select(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer>)source,
                    __lambda));
        }
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "DsycSMkNdv4BbIVBoMKvNoIBAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer> __Polyfill_Where_3e61_14_24(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool> __func)
        {
            // Source: c => c.IsActive() && c.Country == "US"
            var i3e6114c24_p_c = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer), "c");
            var i3e6114c24_expr_1 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.CustomerActiveExt2).GetMethod("IsActive", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer) }, null), new global::System.Linq.Expressions.Expression[] { i3e6114c24_p_c }); // c.IsActive()
            var i3e6114c24_expr_3 = global::System.Linq.Expressions.Expression.Property(i3e6114c24_p_c, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("Country", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // c.Country
            var i3e6114c24_expr_4 = global::System.Linq.Expressions.Expression.Constant("US", typeof(string)); // "US"
            var i3e6114c24_expr_2 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, i3e6114c24_expr_3, i3e6114c24_expr_4);
            var i3e6114c24_expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, i3e6114c24_expr_1, i3e6114c24_expr_2);
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer, bool>>(i3e6114c24_expr_0, i3e6114c24_p_c);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer>)source,
                    __lambda));
        }
    }
}

namespace System.Runtime.CompilerServices
{
    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
    file sealed class InterceptsLocationAttribute : global::System.Attribute
    {
        public InterceptsLocationAttribute(int version, string data) { }
    }
}

Example: Parameterized Filters with Extension Methods

Extension methods are ideal for filters that accept parameters:

db
    .Orders
    .Where(o => o.IsWithinDateRange(new DateTime(2024, 1, 1), new DateTime(2024, 12, 31)))
    .Where(o => o.IsHighValue(500m))

// Setup
public static class OrderParamFilters
{
    [Expressive]
    public static bool IsWithinDateRange(this Order order, DateTime from, DateTime to) =>
        order.PlacedAt >= from && order.PlacedAt <= to;

    [Expressive]
    public static bool IsHighValue(this Order order, decimal threshold) =>
        order.Items.Sum(i => i.UnitPrice * i.Quantity) >= threshold;

    [Expressive]
    public static bool BelongsToCountry(this Order order, string country) =>
        order.Customer != null && order.Customer.Country == country;
}

SELECT "o"."Id", "o"."CustomerId", "o"."PlacedAt", "o"."Status"
FROM "Orders" AS "o"
WHERE "o"."PlacedAt" >= '2024-01-01 00:00:00' AND "o"."PlacedAt" <= '2024-12-31 00:00:00' AND ef_compare((
    SELECT COALESCE(ef_sum(ef_multiply("l"."UnitPrice", CAST("l"."Quantity" AS TEXT))), '0.0')
    FROM "LineItems" AS "l"
    WHERE "o"."Id" = "l"."OrderId"), '500.0') >= 0

// === ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters.IsWithinDateRange_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_System_DateTime_P2_System_DateTime.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters 
    {
        // [Expressive]
        // public static bool IsWithinDateRange(this Order order, DateTime from, DateTime to) => order.PlacedAt >= from && order.PlacedAt <= to;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, global::System.DateTime, global::System.DateTime, bool>> IsWithinDateRange_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_System_DateTime_P2_System_DateTime_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var p_from = global::System.Linq.Expressions.Expression.Parameter(typeof(global::System.DateTime), "from");
            var p_to = global::System.Linq.Expressions.Expression.Parameter(typeof(global::System.DateTime), "to");
            var expr_2 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("PlacedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.PlacedAt
            var expr_1 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.GreaterThanOrEqual, expr_2, p_from, false, typeof(global::System.DateTime).GetMethod("op_GreaterThanOrEqual", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            var expr_4 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("PlacedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.PlacedAt
            var expr_3 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.LessThanOrEqual, expr_4, p_to, false, typeof(global::System.DateTime).GetMethod("op_LessThanOrEqual", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_3);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, global::System.DateTime, global::System.DateTime, bool>>(expr_0, p_order, p_from, p_to);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters.IsHighValue_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_decimal.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters 
    {
        // [Expressive]
        // public static bool IsHighValue(this Order order, decimal threshold) => order.Items.Sum(i => i.UnitPrice * i.Quantity) >= threshold;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, decimal, bool>> IsHighValue_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_decimal_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var p_threshold = global::System.Linq.Expressions.Expression.Parameter(typeof(decimal), "threshold");
            var expr_2 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Items", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Items
            var p_i_3 = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.LineItem), "i"); // i => i.UnitPrice * i.Quantity
            var expr_5 = global::System.Linq.Expressions.Expression.Property(p_i_3, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.LineItem).GetProperty("UnitPrice", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // i.UnitPrice
            var expr_7 = global::System.Linq.Expressions.Expression.Property(p_i_3, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.LineItem).GetProperty("Quantity", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // i.Quantity
            var expr_6 = global::System.Linq.Expressions.Expression.Convert(expr_7, typeof(decimal));
            var expr_4 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Multiply, expr_5, expr_6);
            var expr_8 = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.LineItem, decimal>>(expr_4, p_i_3);
            var expr_1 = global::System.Linq.Expressions.Expression.Call(global::System.Linq.Enumerable.First(global::System.Linq.Enumerable.Where(typeof(global::System.Linq.Enumerable).GetMethods(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static), m => m.Name == "Sum" && m.IsGenericMethodDefinition && m.GetGenericArguments().Length == 1 && m.GetParameters().Length == 2 && m.GetParameters()[0].ParameterType.IsGenericType && !m.GetParameters()[0].ParameterType.IsGenericParameter && m.GetParameters()[1].ParameterType.IsGenericType && !m.GetParameters()[1].ParameterType.IsGenericParameter && m.GetParameters()[1].ParameterType.GetGenericArguments()[1] == typeof(decimal))).MakeGenericMethod(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.LineItem)), new global::System.Linq.Expressions.Expression[] { expr_2, expr_8 });
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.GreaterThanOrEqual, expr_1, p_threshold);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, decimal, bool>>(expr_0, p_order, p_threshold);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters.BelongsToCountry_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_string.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters 
    {
        // [Expressive]
        // public static bool BelongsToCountry(this Order order, string country) => order.Customer != null && order.Customer.Country == country;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, string, bool>> BelongsToCountry_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_string_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var p_country = global::System.Linq.Expressions.Expression.Parameter(typeof(string), "country");
            var expr_2 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Customer", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Customer
            var expr_4 = global::System.Linq.Expressions.Expression.Constant(null, typeof(object)); // null
            var expr_3 = global::System.Linq.Expressions.Expression.Convert(expr_4, typeof(object));
            var expr_1 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.NotEqual, expr_2, expr_3);
            var expr_7 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Customer", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Customer
            var expr_6 = global::System.Linq.Expressions.Expression.Property(expr_7, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("Country", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance));
            var expr_5 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, expr_6, p_country);
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_5);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, string, bool>>(expr_0, p_order, p_country);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters.Attributes.g.cs ===
// <auto-generated/>

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters { }
}


// === ExpressionRegistry.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal static class ExpressionRegistry
    {
        private static Dictionary<nint, LambdaExpression> Build()
        {
            const BindingFlags allFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
            var map = new Dictionary<nint, LambdaExpression>();
            
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderParamFilters).GetMethod("IsWithinDateRange", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), typeof(global::System.DateTime), typeof(global::System.DateTime) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters", "IsWithinDateRange_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_System_DateTime_P2_System_DateTime_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderParamFilters).GetMethod("IsHighValue", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), typeof(decimal) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters", "IsHighValue_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_decimal_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderParamFilters).GetMethod("BelongsToCountry", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), typeof(string) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderParamFilters", "BelongsToCountry_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_P1_string_Expression");
            
            return map;
        }
        
        private static volatile Dictionary<nint, LambdaExpression> _map = Build();
        
        internal static void ResetMap() => _map = Build();
        
        public static LambdaExpression TryGet(MemberInfo member)
        {
            var handle = member switch
            {
                MethodInfo m      => (nint?)m.MethodHandle.Value,
                PropertyInfo p    => p.GetMethod?.MethodHandle.Value,
                ConstructorInfo c => (nint?)c.MethodHandle.Value,
                _                 => null
            };
            
            return handle.HasValue && _map.TryGetValue(handle.Value, out var expr) ? expr : null;
        }
        
        private static void Register(Dictionary<nint, LambdaExpression> map, MethodBase m, string exprClass, string exprMethodName)
        {
            if (m is null) return;
            var exprType = m.DeclaringType?.Assembly.GetType(exprClass) ?? typeof(ExpressionRegistry).Assembly.GetType(exprClass);
            var exprMethod = exprType?.GetMethod(exprMethodName, BindingFlags.Static | BindingFlags.NonPublic);
            if (exprMethod is null) return;
            var expr = (LambdaExpression)exprMethod.Invoke(null, null)!;
            
            // Apply declared transformers from the generated class (if any)
            const string expressionSuffix = "_Expression";
            if (exprMethodName.EndsWith(expressionSuffix, StringComparison.Ordinal))
            {
                var transformersSuffix = exprMethodName.Substring(0, exprMethodName.Length - expressionSuffix.Length) + "_Transformers";
                var transformersMethod = exprType.GetMethod(transformersSuffix, BindingFlags.Static | BindingFlags.NonPublic);
                if (transformersMethod?.Invoke(null, null) is global::ExpressiveSharp.IExpressionTreeTransformer[] transformers)
                {
                    Expression transformed = expr;
                    foreach (var t in transformers) transformed = t.Transform(transformed);
                    if (transformed is LambdaExpression lambdaResult) expr = lambdaResult;
                }
            }
            
            map[m.MethodHandle.Value] = expr;
        }
    }
}


// === PolyfillInterceptors_b1293e61.g.cs ===
// <auto-generated/>
#nullable disable

namespace ExpressiveSharp.Generated.Interceptors
{
    internal static partial class PolyfillInterceptors
    {
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "zJL7wt6wjnSVrJV0vh+93t8BAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> __Polyfill_Where_3e61_16_5(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool> __func)
        {
            // Source: o => o.IsHighValue(500m)
            var i3e6116c5_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var i3e6116c5_expr_1 = global::System.Linq.Expressions.Expression.Constant(500m, typeof(decimal)); // 500m
            var i3e6116c5_expr_0 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderParamFilters).GetMethod("IsHighValue", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), typeof(decimal) }, null), new global::System.Linq.Expressions.Expression[] { i3e6116c5_p_o, i3e6116c5_expr_1 });
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(i3e6116c5_expr_0, i3e6116c5_p_o);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order>)source,
                    __lambda));
        }
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "zJL7wt6wjnSVrJV0vh+93oQBAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> __Polyfill_Where_3e61_15_5(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool> __func)
        {
            // Source: o => o.IsWithinDateRange(new DateTime(2024, 1, 1), new DateTime(2024, 12, 31))
            var i3e6115c5_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var i3e6115c5_expr_2 = global::System.Linq.Expressions.Expression.Constant(2024, typeof(int)); // 2024
            var i3e6115c5_expr_3 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var i3e6115c5_expr_4 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var i3e6115c5_expr_1 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), i3e6115c5_expr_2, i3e6115c5_expr_3, i3e6115c5_expr_4);
            var i3e6115c5_expr_6 = global::System.Linq.Expressions.Expression.Constant(2024, typeof(int)); // 2024
            var i3e6115c5_expr_7 = global::System.Linq.Expressions.Expression.Constant(12, typeof(int)); // 12
            var i3e6115c5_expr_8 = global::System.Linq.Expressions.Expression.Constant(31, typeof(int)); // 31
            var i3e6115c5_expr_5 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), i3e6115c5_expr_6, i3e6115c5_expr_7, i3e6115c5_expr_8);
            var i3e6115c5_expr_0 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderParamFilters).GetMethod("IsWithinDateRange", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), typeof(global::System.DateTime), typeof(global::System.DateTime) }, null), new global::System.Linq.Expressions.Expression[] { i3e6115c5_p_o, i3e6115c5_expr_1, i3e6115c5_expr_5 });
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(i3e6115c5_expr_0, i3e6115c5_p_o);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order>)source,
                    __lambda));
        }
    }
}

namespace System.Runtime.CompilerServices
{
    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
    file sealed class InterceptsLocationAttribute : global::System.Attribute
    {
        public InterceptsLocationAttribute(int version, string data) { }
    }
}

TIP

Parameters (from, to, 500m) are captured as provider parameters -- there is no string concatenation or SQL injection risk.

Example: Composing Filters

Build complex filters by composing simpler [Expressive] members:

db
    .Orders
    .Where(o => o.IsRecentPaidOrder())

// Setup
public static class OrderComposedFilters
{
    [Expressive]
    public static bool IsPaid(this Order o) => o.Status == OrderStatus.Paid;

    [Expressive]
    public static bool IsRecent(this Order o) => o.PlacedAt >= new DateTime(2024, 1, 1);

    // Composed from simpler [Expressive] members
    [Expressive]
    public static bool IsRecentPaidOrder(this Order o) => o.IsPaid() && o.IsRecent();

    [Expressive]
    public static bool IsEligibleForReturn(this Order order) =>
        order.Status == OrderStatus.Delivered
        && order.PlacedAt >= new DateTime(2024, 1, 1);
}

.param set @Paid 1

SELECT "o"."Id", "o"."CustomerId", "o"."PlacedAt", "o"."Status"
FROM "Orders" AS "o"
WHERE "o"."Status" = @Paid AND "o"."PlacedAt" >= '2024-01-01 00:00:00'

// === ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters.IsPaid_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters 
    {
        // [Expressive]
        // public static bool IsPaid(this Order o) => o.Status == OrderStatus.Paid;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsPaid_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var expr_1 = global::System.Linq.Expressions.Expression.Property(p_o, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // o.Status
            var expr_2 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Paid", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Paid
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, expr_1, expr_2);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_o);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters.IsRecent_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters 
    {
        // [Expressive]
        // public static bool IsRecent(this Order o) => o.PlacedAt >= new DateTime(2024, 1, 1);
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsRecent_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var expr_1 = global::System.Linq.Expressions.Expression.Property(p_o, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("PlacedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // o.PlacedAt
            var expr_3 = global::System.Linq.Expressions.Expression.Constant(2024, typeof(int)); // 2024
            var expr_4 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_5 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_2 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), expr_3, expr_4, expr_5);
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.GreaterThanOrEqual, expr_1, expr_2, false, typeof(global::System.DateTime).GetMethod("op_GreaterThanOrEqual", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_o);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters.IsRecentPaidOrder_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters 
    {
        // // Composed from simpler [Expressive] members
        // [Expressive]
        // public static bool IsRecentPaidOrder(this Order o) => o.IsPaid() && o.IsRecent();
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsRecentPaidOrder_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var expr_1 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsPaid", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { p_o }); // o.IsPaid()
            var expr_2 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsRecent", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { p_o }); // o.IsRecent()
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_2);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_o);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters.IsEligibleForReturn_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters 
    {
        // [Expressive]
        // public static bool IsEligibleForReturn(this Order order) => order.Status == OrderStatus.Delivered && order.PlacedAt >= new DateTime(2024, 1, 1);
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsEligibleForReturn_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var expr_2 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Status
            var expr_3 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Delivered", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Delivered
            var expr_1 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, expr_2, expr_3);
            var expr_5 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("PlacedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.PlacedAt
            var expr_7 = global::System.Linq.Expressions.Expression.Constant(2024, typeof(int)); // 2024
            var expr_8 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_9 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_6 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), expr_7, expr_8, expr_9);
            var expr_4 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.GreaterThanOrEqual, expr_5, expr_6, false, typeof(global::System.DateTime).GetMethod("op_GreaterThanOrEqual", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_4);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_order);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters.Attributes.g.cs ===
// <auto-generated/>

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters { }
}


// === ExpressionRegistry.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal static class ExpressionRegistry
    {
        private static Dictionary<nint, LambdaExpression> Build()
        {
            const BindingFlags allFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
            var map = new Dictionary<nint, LambdaExpression>();
            
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsPaid", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters", "IsPaid_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsRecent", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters", "IsRecent_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsRecentPaidOrder", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters", "IsRecentPaidOrder_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsEligibleForReturn", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderComposedFilters", "IsEligibleForReturn_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            
            return map;
        }
        
        private static volatile Dictionary<nint, LambdaExpression> _map = Build();
        
        internal static void ResetMap() => _map = Build();
        
        public static LambdaExpression TryGet(MemberInfo member)
        {
            var handle = member switch
            {
                MethodInfo m      => (nint?)m.MethodHandle.Value,
                PropertyInfo p    => p.GetMethod?.MethodHandle.Value,
                ConstructorInfo c => (nint?)c.MethodHandle.Value,
                _                 => null
            };
            
            return handle.HasValue && _map.TryGetValue(handle.Value, out var expr) ? expr : null;
        }
        
        private static void Register(Dictionary<nint, LambdaExpression> map, MethodBase m, string exprClass, string exprMethodName)
        {
            if (m is null) return;
            var exprType = m.DeclaringType?.Assembly.GetType(exprClass) ?? typeof(ExpressionRegistry).Assembly.GetType(exprClass);
            var exprMethod = exprType?.GetMethod(exprMethodName, BindingFlags.Static | BindingFlags.NonPublic);
            if (exprMethod is null) return;
            var expr = (LambdaExpression)exprMethod.Invoke(null, null)!;
            
            // Apply declared transformers from the generated class (if any)
            const string expressionSuffix = "_Expression";
            if (exprMethodName.EndsWith(expressionSuffix, StringComparison.Ordinal))
            {
                var transformersSuffix = exprMethodName.Substring(0, exprMethodName.Length - expressionSuffix.Length) + "_Transformers";
                var transformersMethod = exprType.GetMethod(transformersSuffix, BindingFlags.Static | BindingFlags.NonPublic);
                if (transformersMethod?.Invoke(null, null) is global::ExpressiveSharp.IExpressionTreeTransformer[] transformers)
                {
                    Expression transformed = expr;
                    foreach (var t in transformers) transformed = t.Transform(transformed);
                    if (transformed is LambdaExpression lambdaResult) expr = lambdaResult;
                }
            }
            
            map[m.MethodHandle.Value] = expr;
        }
    }
}


// === PolyfillInterceptors_b1293e61.g.cs ===
// <auto-generated/>
#nullable disable

namespace ExpressiveSharp.Generated.Interceptors
{
    internal static partial class PolyfillInterceptors
    {
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "2xoKPlGW3KD11HjG1Xd4cn8BAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> __Polyfill_Where_3e61_14_21(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool> __func)
        {
            // Source: o => o.IsRecentPaidOrder()
            var i3e6114c21_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var i3e6114c21_expr_0 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderComposedFilters).GetMethod("IsRecentPaidOrder", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { i3e6114c21_p_o }); // o.IsRecentPaidOrder()
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(i3e6114c21_expr_0, i3e6114c21_p_o);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order>)source,
                    __lambda));
        }
    }
}

namespace System.Runtime.CompilerServices
{
    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
    file sealed class InterceptsLocationAttribute : global::System.Attribute
    {
        public InterceptsLocationAttribute(int version, string data) { }
    }
}

The composed filters are expanded recursively -- IsRecentPaidOrder references IsPaid and IsRecent, which are both expanded to their underlying expressions before translation.

Example: Global Query Filters with EF Core

[Expressive] properties work in EF Core's global query filters (configured in OnModelCreating):

csharp

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
    // Active-order global filter using an [Expressive] extension
    modelBuilder.Entity<Order>()
        .HasQueryFilter(o => o.Status != OrderStatus.Refunded);

    // Tenant isolation filter
    modelBuilder.Entity<Order>()
        .HasQueryFilter(o => o.CustomerId == _currentCustomerId);
}

INFO

When using global query filters, ensure that UseExpressives() is configured on your DbContext. The library includes a convention that expands [Expressive] member references in global filters automatically.

csharp

// Bypass the global filter when needed
var allOrders = dbContext.Orders
    .IgnoreQueryFilters()
    .ToList();

Example: Specification Pattern

[Expressive] members pair naturally with the Specification pattern:

db
    .Orders
    .Where(o => o.RequiresAttention())
    .Select(o => o.Id)

// Setup
public static class OrderSpecifications
{
    [Expressive]
    public static bool IsActive(this Order order) =>
        order.Status != OrderStatus.Refunded;

    [Expressive]
    public static bool IsOverdue(this Order order) =>
        order.IsActive()
        && order.PlacedAt < new DateTime(2024, 6, 1)
        && order.Status == OrderStatus.Pending;

    [Expressive]
    public static bool RequiresAttention(this Order order) =>
        order.IsOverdue()
        || order.Status == OrderStatus.Pending;
}

.param set @Refunded 4
.param set @Pending 0

SELECT "o"."Id"
FROM "Orders" AS "o"
WHERE ("o"."Status" <> @Refunded AND "o"."PlacedAt" < '2024-06-01 00:00:00' AND "o"."Status" = @Pending) OR "o"."Status" = @Pending

// === ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications.IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications 
    {
        // [Expressive]
        // public static bool IsActive(this Order order) => order.Status != OrderStatus.Refunded;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var expr_1 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Status
            var expr_2 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Refunded", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Refunded
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.NotEqual, expr_1, expr_2);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_order);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications.IsOverdue_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications 
    {
        // [Expressive]
        // public static bool IsOverdue(this Order order) => order.IsActive() && order.PlacedAt < new DateTime(2024, 6, 1) && order.Status == OrderStatus.Pending;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsOverdue_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var expr_2 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderSpecifications).GetMethod("IsActive", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { p_order }); // order.IsActive()
            var expr_4 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("PlacedAt", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.PlacedAt
            var expr_6 = global::System.Linq.Expressions.Expression.Constant(2024, typeof(int)); // 2024
            var expr_7 = global::System.Linq.Expressions.Expression.Constant(6, typeof(int)); // 6
            var expr_8 = global::System.Linq.Expressions.Expression.Constant(1, typeof(int)); // 1
            var expr_5 = global::System.Linq.Expressions.Expression.New(typeof(global::System.DateTime).GetConstructor(global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance, null, new global::System.Type[] { typeof(int), typeof(int), typeof(int) }, null), expr_6, expr_7, expr_8);
            var expr_3 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.LessThan, expr_4, expr_5, false, typeof(global::System.DateTime).GetMethod("op_LessThan", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::System.DateTime), typeof(global::System.DateTime) }, null));
            var expr_1 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_2, expr_3);
            var expr_10 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Status
            var expr_11 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Pending", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Pending
            var expr_9 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, expr_10, expr_11);
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, expr_1, expr_9);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_order);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications.RequiresAttention_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications 
    {
        // [Expressive]
        // public static bool RequiresAttention(this Order order) => order.IsOverdue() || order.Status == OrderStatus.Pending;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> RequiresAttention_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var expr_1 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderSpecifications).GetMethod("IsOverdue", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { p_order }); // order.IsOverdue()
            var expr_3 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Status
            var expr_4 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Pending", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Pending
            var expr_2 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, expr_3, expr_4);
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.OrElse, expr_1, expr_2);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_order);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications.Attributes.g.cs ===
// <auto-generated/>

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications { }
}


// === ExpressionRegistry.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal static class ExpressionRegistry
    {
        private static Dictionary<nint, LambdaExpression> Build()
        {
            const BindingFlags allFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
            var map = new Dictionary<nint, LambdaExpression>();
            
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderSpecifications).GetMethod("IsActive", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications", "IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderSpecifications).GetMethod("IsOverdue", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications", "IsOverdue_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderSpecifications).GetMethod("RequiresAttention", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderSpecifications", "RequiresAttention_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            
            return map;
        }
        
        private static volatile Dictionary<nint, LambdaExpression> _map = Build();
        
        internal static void ResetMap() => _map = Build();
        
        public static LambdaExpression TryGet(MemberInfo member)
        {
            var handle = member switch
            {
                MethodInfo m      => (nint?)m.MethodHandle.Value,
                PropertyInfo p    => p.GetMethod?.MethodHandle.Value,
                ConstructorInfo c => (nint?)c.MethodHandle.Value,
                _                 => null
            };
            
            return handle.HasValue && _map.TryGetValue(handle.Value, out var expr) ? expr : null;
        }
        
        private static void Register(Dictionary<nint, LambdaExpression> map, MethodBase m, string exprClass, string exprMethodName)
        {
            if (m is null) return;
            var exprType = m.DeclaringType?.Assembly.GetType(exprClass) ?? typeof(ExpressionRegistry).Assembly.GetType(exprClass);
            var exprMethod = exprType?.GetMethod(exprMethodName, BindingFlags.Static | BindingFlags.NonPublic);
            if (exprMethod is null) return;
            var expr = (LambdaExpression)exprMethod.Invoke(null, null)!;
            
            // Apply declared transformers from the generated class (if any)
            const string expressionSuffix = "_Expression";
            if (exprMethodName.EndsWith(expressionSuffix, StringComparison.Ordinal))
            {
                var transformersSuffix = exprMethodName.Substring(0, exprMethodName.Length - expressionSuffix.Length) + "_Transformers";
                var transformersMethod = exprType.GetMethod(transformersSuffix, BindingFlags.Static | BindingFlags.NonPublic);
                if (transformersMethod?.Invoke(null, null) is global::ExpressiveSharp.IExpressionTreeTransformer[] transformers)
                {
                    Expression transformed = expr;
                    foreach (var t in transformers) transformed = t.Transform(transformed);
                    if (transformed is LambdaExpression lambdaResult) expr = lambdaResult;
                }
            }
            
            map[m.MethodHandle.Value] = expr;
        }
    }
}


// === PolyfillInterceptors_b1293e61.g.cs ===
// <auto-generated/>
#nullable disable

namespace ExpressiveSharp.Generated.Interceptors
{
    internal static partial class PolyfillInterceptors
    {
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "clAPRShhGEyVDe8+DIQHiKEBAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<int> __Polyfill_Select_3e61_14_55(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, int> __func)
        {
            // Source: o => o.Id
            var i3e6114c55_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var i3e6114c55_expr_0 = global::System.Linq.Expressions.Expression.Property(i3e6114c55_p_o, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Id", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // o.Id
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, int>>(i3e6114c55_expr_0, i3e6114c55_p_o);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Select(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order>)source,
                    __lambda));
        }
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "clAPRShhGEyVDe8+DIQHiH8BAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> __Polyfill_Where_3e61_14_21(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool> __func)
        {
            // Source: o => o.RequiresAttention()
            var i3e6114c21_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var i3e6114c21_expr_0 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderSpecifications).GetMethod("RequiresAttention", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { i3e6114c21_p_o }); // o.RequiresAttention()
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(i3e6114c21_expr_0, i3e6114c21_p_o);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order>)source,
                    __lambda));
        }
    }
}

namespace System.Runtime.CompilerServices
{
    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
    file sealed class InterceptsLocationAttribute : global::System.Attribute
    {
        public InterceptsLocationAttribute(int version, string data) { }
    }
}

All specification methods are expanded recursively -- RequiresAttention calls IsOverdue, which calls IsActive. The entire chain becomes a flat WHERE clause.

Using Filters with ExpressiveDbSet

With ExpressiveDbSet<T>, you can combine [Expressive] filters with inline modern syntax:

db
    .Orders
    .Where(o => o.IsActive() && o.Customer.Country == "US")
    .Select(o => new
    {
        o.Id,
        StatusLabel = o.Status switch
        {
            OrderStatus.Paid => "Paid",
            OrderStatus.Pending => "Pending",
            _ => "Other"
        }
    })

// Setup
public static class OrderActiveForDbSet
{
    [Expressive]
    public static bool IsActive(this Order order) =>
        order.Status != OrderStatus.Refunded;
}

.param set @Paid 1
.param set @Pending 0
.param set @Refunded 4

SELECT "o"."Id", CASE
    WHEN "o"."Status" = @Paid THEN 'Paid'
    WHEN "o"."Status" = @Pending THEN 'Pending'
    ELSE 'Other'
END AS "StatusLabel"
FROM "Orders" AS "o"
INNER JOIN "Customers" AS "c" ON "o"."CustomerId" = "c"."Id"
WHERE "o"."Status" <> @Refunded AND "c"."Country" = 'US'

// === ExpressiveSharp_Docs_Playground_Snippet_OrderActiveForDbSet.IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Linq;
using System.Linq.Expressions;
using ExpressiveSharp;
using ExpressiveSharp.EntityFrameworkCore;
using ExpressiveSharp.Docs.PlaygroundModel.Webshop;
using ExpressiveSharp.Docs.Playground.Snippet;

namespace ExpressiveSharp.Generated
{
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderActiveForDbSet 
    {
        // [Expressive]
        // public static bool IsActive(this Order order) => order.Status != OrderStatus.Refunded;
        static global::System.Linq.Expressions.Expression<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>> IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression() 
        {
            var p_order = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "order");
            var expr_1 = global::System.Linq.Expressions.Expression.Property(p_order, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // order.Status
            var expr_2 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Refunded", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Refunded
            var expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.NotEqual, expr_1, expr_2);
            return global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(expr_0, p_order);
        }
    }
}


// === ExpressiveSharp_Docs_Playground_Snippet_OrderActiveForDbSet.Attributes.g.cs ===
// <auto-generated/>

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    static partial class ExpressiveSharp_Docs_Playground_Snippet_OrderActiveForDbSet { }
}


// === ExpressionRegistry.g.cs ===
// <auto-generated/>
#nullable disable

using System;
using System.Collections.Generic;
using System.Linq.Expressions;
using System.Reflection;

namespace ExpressiveSharp.Generated
{
    [global::System.ComponentModel.EditorBrowsable(global::System.ComponentModel.EditorBrowsableState.Never)]
    internal static class ExpressionRegistry
    {
        private static Dictionary<nint, LambdaExpression> Build()
        {
            const BindingFlags allFlags = BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.Static;
            var map = new Dictionary<nint, LambdaExpression>();
            
            Register(map, typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderActiveForDbSet).GetMethod("IsActive", allFlags, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), "ExpressiveSharp.Generated.ExpressiveSharp_Docs_Playground_Snippet_OrderActiveForDbSet", "IsActive_P0_ExpressiveSharp_Docs_PlaygroundModel_Webshop_Order_Expression");
            
            return map;
        }
        
        private static volatile Dictionary<nint, LambdaExpression> _map = Build();
        
        internal static void ResetMap() => _map = Build();
        
        public static LambdaExpression TryGet(MemberInfo member)
        {
            var handle = member switch
            {
                MethodInfo m      => (nint?)m.MethodHandle.Value,
                PropertyInfo p    => p.GetMethod?.MethodHandle.Value,
                ConstructorInfo c => (nint?)c.MethodHandle.Value,
                _                 => null
            };
            
            return handle.HasValue && _map.TryGetValue(handle.Value, out var expr) ? expr : null;
        }
        
        private static void Register(Dictionary<nint, LambdaExpression> map, MethodBase m, string exprClass, string exprMethodName)
        {
            if (m is null) return;
            var exprType = m.DeclaringType?.Assembly.GetType(exprClass) ?? typeof(ExpressionRegistry).Assembly.GetType(exprClass);
            var exprMethod = exprType?.GetMethod(exprMethodName, BindingFlags.Static | BindingFlags.NonPublic);
            if (exprMethod is null) return;
            var expr = (LambdaExpression)exprMethod.Invoke(null, null)!;
            
            // Apply declared transformers from the generated class (if any)
            const string expressionSuffix = "_Expression";
            if (exprMethodName.EndsWith(expressionSuffix, StringComparison.Ordinal))
            {
                var transformersSuffix = exprMethodName.Substring(0, exprMethodName.Length - expressionSuffix.Length) + "_Transformers";
                var transformersMethod = exprType.GetMethod(transformersSuffix, BindingFlags.Static | BindingFlags.NonPublic);
                if (transformersMethod?.Invoke(null, null) is global::ExpressiveSharp.IExpressionTreeTransformer[] transformers)
                {
                    Expression transformed = expr;
                    foreach (var t in transformers) transformed = t.Transform(transformed);
                    if (transformed is LambdaExpression lambdaResult) expr = lambdaResult;
                }
            }
            
            map[m.MethodHandle.Value] = expr;
        }
    }
}


// === PolyfillInterceptors_b1293e61.g.cs ===
// <auto-generated/>
#nullable disable

namespace ExpressiveSharp.Generated.Interceptors
{
    internal static partial class PolyfillInterceptors
    {
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "TIpck8hPSLOT9AYEb1m1XcABAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<T1> __Polyfill_Select_3e61_16_5<T0, T1>(
            this global::ExpressiveSharp.IExpressiveQueryable<T0> source,
            global::System.Func<T0, T1> __func)
        {
            // Source: o => new { o.Id, StatusLabel = o.Status switch {     OrderStatus.Paid => "Paid",     OrderStatus.Pending => "Pending",     _ => "Other" } }
            var i3e6116c5_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(T0), "o");
            var i3e6116c5_expr_1 = global::System.Linq.Expressions.Expression.Property(i3e6116c5_p_o, typeof(T0).GetProperty("Id", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // o.Id
            var i3e6116c5_expr_2 = global::System.Linq.Expressions.Expression.Property(i3e6116c5_p_o, typeof(T0).GetProperty("Status", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // o.Status
            var i3e6116c5_expr_3 = global::System.Linq.Expressions.Expression.Constant("Other", typeof(string)); // "Other"
            var i3e6116c5_expr_5 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Pending", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Pending
            var i3e6116c5_expr_4 = global::System.Linq.Expressions.Expression.Equal(i3e6116c5_expr_2, i3e6116c5_expr_5);
            var i3e6116c5_expr_6 = global::System.Linq.Expressions.Expression.Constant("Pending", typeof(string)); // "Pending"
            var i3e6116c5_expr_7 = global::System.Linq.Expressions.Expression.Condition(i3e6116c5_expr_4, i3e6116c5_expr_6, i3e6116c5_expr_3, typeof(string));
            var i3e6116c5_expr_9 = global::System.Linq.Expressions.Expression.Field(null, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.OrderStatus).GetField("Paid", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static)); // OrderStatus.Paid
            var i3e6116c5_expr_8 = global::System.Linq.Expressions.Expression.Equal(i3e6116c5_expr_2, i3e6116c5_expr_9);
            var i3e6116c5_expr_10 = global::System.Linq.Expressions.Expression.Constant("Paid", typeof(string)); // "Paid"
            var i3e6116c5_expr_11 = global::System.Linq.Expressions.Expression.Condition(i3e6116c5_expr_8, i3e6116c5_expr_10, i3e6116c5_expr_7, typeof(string));
            var i3e6116c5_expr_12 = typeof(T1).GetConstructors()[0];
            var i3e6116c5_expr_0 = global::System.Linq.Expressions.Expression.New(i3e6116c5_expr_12, new global::System.Linq.Expressions.Expression[] { i3e6116c5_expr_1, i3e6116c5_expr_11 }, new global::System.Reflection.MemberInfo[] { typeof(T1).GetProperty("Id"), typeof(T1).GetProperty("StatusLabel") });
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<T0, T1>>(i3e6116c5_expr_0, i3e6116c5_p_o);
            return (global::ExpressiveSharp.IExpressiveQueryable<T1>)(object)
                global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                    global::System.Linq.Queryable.Select(
                        (global::System.Linq.IQueryable<T0>)(object)source,
                        __lambda));
        }
        [global::System.Runtime.CompilerServices.InterceptsLocationAttribute(1, "TIpck8hPSLOT9AYEb1m1XYQBAABfX1NuaXBwZXQuY3M=")]
        internal static global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> __Polyfill_Where_3e61_15_5(
            this global::ExpressiveSharp.IExpressiveQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order> source,
            global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool> __func)
        {
            // Source: o => o.IsActive() && o.Customer.Country == "US"
            var i3e6115c5_p_o = global::System.Linq.Expressions.Expression.Parameter(typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order), "o");
            var i3e6115c5_expr_1 = global::System.Linq.Expressions.Expression.Call(typeof(global::ExpressiveSharp.Docs.Playground.Snippet.OrderActiveForDbSet).GetMethod("IsActive", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Static, null, new global::System.Type[] { typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order) }, null), new global::System.Linq.Expressions.Expression[] { i3e6115c5_p_o }); // o.IsActive()
            var i3e6115c5_expr_4 = global::System.Linq.Expressions.Expression.Property(i3e6115c5_p_o, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order).GetProperty("Customer", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance)); // o.Customer
            var i3e6115c5_expr_3 = global::System.Linq.Expressions.Expression.Property(i3e6115c5_expr_4, typeof(global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Customer).GetProperty("Country", global::System.Reflection.BindingFlags.Public | global::System.Reflection.BindingFlags.NonPublic | global::System.Reflection.BindingFlags.Instance));
            var i3e6115c5_expr_5 = global::System.Linq.Expressions.Expression.Constant("US", typeof(string)); // "US"
            var i3e6115c5_expr_2 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.Equal, i3e6115c5_expr_3, i3e6115c5_expr_5);
            var i3e6115c5_expr_0 = global::System.Linq.Expressions.Expression.MakeBinary(global::System.Linq.Expressions.ExpressionType.AndAlso, i3e6115c5_expr_1, i3e6115c5_expr_2);
            var __lambda = global::System.Linq.Expressions.Expression.Lambda<global::System.Func<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order, bool>>(i3e6115c5_expr_0, i3e6115c5_p_o);
            return global::ExpressiveSharp.ExpressiveQueryableExtensions.AsExpressive(
                global::System.Linq.Queryable.Where(
                    (global::System.Linq.IQueryable<global::ExpressiveSharp.Docs.PlaygroundModel.Webshop.Order>)source,
                    __lambda));
        }
    }
}

namespace System.Runtime.CompilerServices
{
    [global::System.AttributeUsage(global::System.AttributeTargets.Method, AllowMultiple = true)]
    file sealed class InterceptsLocationAttribute : global::System.Attribute
    {
        public InterceptsLocationAttribute(int version, string data) { }
    }
}

See Modern Syntax in LINQ Chains for more on this approach.

Tips

Compose at the member level

Compose filters inside [Expressive] members rather than chaining multiple .Where() calls. This creates more reusable building blocks.

Name clearly

Use names that express business intent (IsEligibleForRefund) rather than technical details (HasRefundDateNullAndStatusIsComplete).

Prefer entity-level properties for entity-specific filters

Use extension methods for cross-entity or parameterized filters.

Keep filters pure

Filter members should only read data, never modify it. Everything in the body must be translatable by your provider.

Reusable Query Filters ​

The Pattern ​

Example: Active Entity Filter ​

Example: Parameterized Filters with Extension Methods ​

Example: Composing Filters ​

Example: Global Query Filters with EF Core ​

Example: Specification Pattern ​

Using Filters with ExpressiveDbSet ​

Tips ​

See Also ​