The Timeless Marriage: GoF Visitor, LINQ Expression Trees, and Why 30-Year-Old Patterns Still Ship Code

Patterns Don't Die — They Get Promoted to the Standard Library LINQ: Still Beautiful After All These Years The Marriage: How LINQ Queries Actually Work What Else Can This Marriage Do? HashCodeVisitor: The Simplest Visitor You'll Ever Write DeepEqualsComparer: The Kitchen Fight that Copilot Won The Serialization Visitors: Where the Boring Details Live A Word on Security (Yes, Again) Performance: XML vs JSON, and the Validation Tax Document Validation: Two Implementations, One Honest Recommendatio