DeHL (Delphi Helper Library) is discontinued starting with 09.01.2012. You can reuse parts of this project for whatever particular needs you have. The source code is BSD licensed.

The most important features of DeHL for now are:

• A set of generic collections classes (TList, TDictionary, THashSet, TMultiMap, TPriorityQueue and etc).
• Linq-like extensions (called Enex) for collections which allow writing queries on collection classes.
• Date/Time functionality all combined in a few structures (somehow equivalent to .NET's DateTime structure)
• Type Support concept that defines a set of default "support classes" for each built-in Delphi types (used as defaults in collections). Custom "type support" classes can be registered for your custom data types.
• BigCardinal and BigInteger data types.
• BigDecimal for infinite precision Decimal calculus
• Scoped objects in Delphi.
• Nullable types in Delphi.
• Tuples
• Array extensions and utilities.
• Wide charset implementation.
• OOP TString type.
• Full generic serialization for all included types and collections.
• Type conversion system with custom conversion support.
• ... and more!

All classes and functions have unit tests. We're trying to maintain a large set of tests to find and fix early all possible bugs.