CS 4448 - Spring 1998
Object-Oriented Programming and Design
Talk 6.2.2
by
Adam Patacchiola

Summary of Eiffel Discussion

• Eiffel is more than just another OO language.
• It is a complete development environment, which includes tools for:
• Analysis
• Design
• Implementation
• Why is eiffel so great?
• It uses a simple, powerful language and method.
• It is seamless, providing a single thread throughout the software lifecycle.
• Designed to be completely OO from the ground up.
• Allows elements of different languages (such as C or C++) to be used together.
• Very reliable due to unique Design by Contract feature.
• Eiffel is available for a variety of platforms including:
• Windows (NT,95)
• Unix
• Solaris
• SunOS
• HP 9000
• IBM AIX
• Linux
• Unixware
• Silicon Graphics
• Data General
• Fujitsu
• DEC OSF/1
• etc.
• VMS
• Alpha
• Vax
• Source code is compatible between platforms.
• Eiffel can be used with existing software.
• Possesses sophisticated C/C++ interface which supports:
• Calling C functions from Eiffel
• Accessing C++ classes and components from Eiffel.
• Accessing Eiffel mechanisms from C or C++ through Cecil library (C-Eiffel Call-In Library)
• Automatically produdig a "wrapper" Eiffel class from a C++ class.
• Similar in speed to C and Fortran, and better in some cases.
• Uses special "Melting Ice" compilation technology.
• Combines compilation with bytecode interpretation to generate efficient code while allowing for fast recompiles to test new implementation changes.
• Final version of code translated into C to allow for optimizations and permitting excellent performance.
• Eiffel written in itself.
• Provides lots of libraries which include:
• Graphical libraries for:
• Windows 95/NT
• OS/2
• Motif
• Relational database library.
• Math, Data Structures, Web, Internet, etc. Libraries.
• Designed from day one to provide excellent reuse of code.
• Includes unique Design by Contract feature.
• Built in reliability mechanism called assestions, directly enforced through class:
• Invariants
• Preconditions
• Postconditions
• For example, a precondition on a file opening routine may express that the file must be readable.
• Very powerful mechanism to ensure correctness of program.
• Build software together with the arguments that justify it's correctness.
• Can select different levels of assertion checking for each class.
• Allows for easy documentation of classes through automatically generated short form which hides the implementation but shows the interface and assertions.
• Supports inheritance and clean mulitple inheritance.
• Renaming mechanism to eliminated name clashes.
• Selection facility to remove ambiguities resulting from multiple redeclarations.
• Statically typed
• Ensures errors caught at compile time, not run time.
• Dynamically bound
• Guarantees that the right version of an operation will always be applied depending on the target object.