Introduction

The tracing facility allows you to see a structured log of the flow of control through your system, feature by feature. By default, execution traces are written to standard output.

Note: The tracing facility is not supported on the Microsoft .NET platform.

The "Trace" project setting

You can make tracing usable for a particular cluster by setting the Trace setting to True in your project settings for a particular cluster.

To do this:

• Open the Project Settings dialog.

Instructions

Eiffel has a remarkably small set of instructions. The basic computational instructions have been seen: creation, assignment, procedure call, retry. They are complemented by control structures: conditional, multi-branch, loop, as well as debug and check.

Assignment and attachment

As noted above we have already introduced assignment. But let's take another look at the assignment in the context of the more abstract concept of attachment.

A debugger is a tool that allows you to run an application and view its state at any moment. This includes having information concerning the current call stack and the state of objects of the system, i.e. the values of their attributes. This kind of information can be used to spot objects that have invalid states, to see the consequences of the execution of a feature over an object state, and so on.