Introduction
Reflection in programming is a fundamental technique where you examine the state of your program at a particular point in time. This allows you to understand how the program has evolved, identify potential issues, and plan for future changes. It's not about re-writing the code, but about *observing* it.
It is crucial for debugging, performance analysis, and understanding complex control flows. It helps in identifying hotspots where code is executed repeatedly, leading to optimizations.
The core principle is to understand the past behavior of the code to help predict its future behavior.
Key Concepts
• **Call Stack:** The chain of calls that led to the current point of execution.
• **State:** The current values of variables and data within the program.
• **Reflection:** The process of examining a program's structure and code at runtime.
• Context:** The parameters passed to functions or methods. Crucially important for understanding how a function operates.
Example - Reflection in Action
Consider a simple function that increments a counter. When called, it will: 1. Execute the function body. 2. Set the counter variable. 3. Execute the function body again. This creates a stack of function calls.
Understanding this allows you to see how the counter gets modified, and potentially find bugs, and to make the program more efficient.