9: Mainline

The enormous power of Smalltalk development environments is derived from an unusual armamentarium of powerful tools:

• Smalltalk development environments provide powerful browsers that allow you to examine all class and method definitions—even the built-in classes and methods.
• Smalltalk development environments provide powerful debugging tools. Using these tools, you see the message sequences that lead to program interruption, you inspect parameter and variable values to zero in on errors, you modify method definitions, and you restart or resume your interrupted program.
• Smalltalk classes and methods are compiled as you write them, incrementally. You never have to waste time waiting for a compiler to translate an entire program or program module into machine instructions.