匿名方法的乐趣：在 Delphi 中使用高阶函数

发布于 2019-01-07

Since 2009: Delphi language (Object Pascal dialect) has supported anonymous methods.
- What Is an Anonymous Method: It's a procedure or function without a name, treats code block as a value, can refer to variables and bind values. Declared as a reference to a function.
- Higher-Order Functions: In mathematics and computer science, a function that takes or outputs other functions. Includes Map, Reduce, and Filter.
Getting Ready: Use Delphi's anonymous methods with popular higher-order functions.
- Map: Takes a function and a list, returns a new list with function applied to each element.
- Reduce: Combines elements of a data structure using an injected function, starting from a default value.
- Filter: Returns elements in a structure that match a filter condition.
How to Do It:
- Implement higher-order functions in the HigherOrderFunctionsU.pas unit as generic class functions.
- Map function example: Maps each element of an input data structure and builds a new list.
- Reduce function example: Sums elements of an input data structure using a specified function and a starting value.
- Filter function example: Filters an input data structure based on a filter condition.
There's More: Higher-order functions are a vast topic. One example is the parallel extension of the OmniThreadLibrary using anonymous methods and multiple threads.
Reference: The code is from the third edition of "Delphi Cookbook" by Daniele Teti and Daniele Spinetti published by Packt. It can be used as a development guide or reference.

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