Eiffel programming languageFeaturesElegance, simplicity, or fascism?Lexical simplicitySyntactic simplicityNon-OO operationsHello World in EiffelEiffel programming language Eiffel was created in 1987 by Bertrand Meyer his company Interactive Software Engineering (ISE). It closely follows Dr. Meyer's work in Object Oriented Software Construction, Second Edition. Eiffel differs from most popular languages in several ways. Eiffel is an object-oriented (OO) programming language which emphasizes the production of robust software. Many find its syntax to be reminiscent of Pascal. Eiffel is strongly statically typed, with automatic memory management (typically implemented by garbage collection). Eiffel is a mature OO language with a generally excellent reputation among those who are familiar with the language. However, Eiffel has failed to gain much interest from software developers. The reasons for this lack of interest are unclear, and are a topic of frequent discussion within the Eiffel community. Distinguishing characteristics of Eiffel include Design by Contract™, liberal use of implementation inheritance including multiple inheritance, value types implemented via value semantics, and generic classes. Eiffel has a unified type system—because all types in Eiffel are classes, it is possible to create subclasses of the basic classes such as INTEGER. Eiffel has operator overloading, including the ability to define new operators, but does not have method overloading. The aim of Eiffel is to improve the quality of software systems and the productivity of the development process. It particularly promotes the production of software that has the following qualities: reliability (absence of bugs) extendibility (ease of change) reusability (reliance of libraries of packaged components) and portability (adaptability on many platforms with full source compatibility). It supports multiple inheritance, genericity, polymorphism, and encapsulation. Its most important contribution to software engineering is Design by Contract, in which assertions, preconditions, postconditions, and class invariants are used to assist in assuring program correctness without sacrificing efficiency. Eiffel also makes it possible to produce compilers, such as ISE's, which generate extremely efficient code. Eiffel also offers multiple class inheritance. Many people (such as the designers of Java) have objections to multiple inheritance. The Eiffel implementation of multiple inheritance, in the opinion of its supporters, successfully meets these objections.Eiffel's design is closely based on OOP theory, with less influence from other paradigms or support for legacy code. The language has formal support for abstract data types. In accordance with Self Documentation, a software text should be able to reproduce its design documentation from the text itself. Eiffel accomplishes this by using a formalized implementation of the Abstract Data Type. Eiffel Studio, an integrated development environment for Eiffel, offers an object-oriented interface for software engineering. However, many programmers disliked it because it was very different from user interfaces for other integrated development environments. Features As a language Eiffel is a "pure" object-oriented language (arguably the most systematic application of object-oriented principles in existing languages) based on a small number of powerful concepts:   Seamless development: Eiffel is applicable to the entire lifecycle, from analysis and high-level design to implementation and maintenance, providing a single conceptual framework throughout the software process.   Classes, serving as the sole basis for both the module structure and the type system.   Inheritance for classification, subtype and reuse.   A careful and effective approach to multiple inheritance (renaming, selection, redefinition, undefinition, repeated inheritance).   Assertions for writing correct and robust software, debugging it, and documenting it automatically.   Disciplined exception handling to recover gracefully from abnormal cases.   Static typing with no loopholes in the type system for safety.   Dynamic binding for flexibility and safety.   Genericity, constrained and unconstrained, for describing flexible container structures.   Open architecture providing easy access to software written in other languages such as C, C++ and others. Elegance, simplicity, or fascism?The Eiffel language aims to promote clear and elegant coding. Eiffel emphasizes declarative statements over procedural code, and it eliminates the need for bookkeeping instructions. More controversially, Eiffel intentionally limits stylistic expression, providing no room for clever coding tricks or coding techniques intended as optimization hints to the compiler. Some software developers feel constrained by Eiffel's simplicity, sometimes to the extent of describing Eiffel programming as "bondage and discipline". Lexical simplicity Eiffel is not case-sensitive. Both keywords and identifiers can be written in any combination of upper and lower case. The tokens MaKe and make and MAKE all refer to the same identifier. Coding style standards, however, generally prescribe the use of all-capitals for class names, all lower-case for variables and method names, and initial capitals for constants. Eiffel's syntax can be parsed without requiring end-of-statement markers. The use of semicolons as statement terminators or as statement separators is left to the discretion of the programmer. Putting a semicolon in or leaving one out will make no difference except in the unusual case of a statement starting with a left parenthesis. Most Eiffel programmers choose to omit semicolons except when putting multiple statements on a line. Eiffel requires that sections and clauses appear in a specific order. In contrast to most members of the curly brace family of programming languages, Eiffel does not permit expressions to be used as statements, nor statements to be used as expressions. Accordingly, a method which returns a value can only be used in expressions, while a method which does not return a value can only be invoked by method call statements. This philosophy—that expressions and statements are fundamentally different in nature—is expanded into the concept of Command-Query Separation (CQS). Under CQS, a query method (a function which returns a