LANGUAGE CATEGORIES

• Programming languages are often categorized into four bins:
1. Imperative
2. Functional
3. logic, and
4. object oriented
• languages that support object-oriented programming to form a separate category of languages.
• The most popular languages that support object-oriented programming grew out of imperative languages.
• Although the object-oriented software development paradigm differs significantly from the procedure-oriented paradigm usually used with imperative languages, the extensions to an imperative language required to support object-oriented programming are not intensive.
• For example, the expressions, assignment statements, and control statements of C and Java are nearly identical. Similar statements can be made for functional languages that support object-oriented programming.
• Another kind of language, the visual language, is a subcategory of the imperative languages.
• The most popular visual languages are the .NET languages. These languages include capabilities for drag-and-drop generation of code segments.
• Such languages were once called fourth-generation languages, although that name has fallen out of use.
• The visual languages provide a simple way to generate graphical user interfaces to programs.
• For example, using Visual Studio to develop software in the .NET languages, the code to produce a display of a form control, such as a button or text box, can be created with a single keystroke.
• These capabilities are now available in all of the .NET languages.
• Languages in this category are bound together more by their implementation method, partial or full interpretation, than by a common language design.
• The languages that are typically called scripting languages, among them Perl, JavaScript, and Ruby, are imperative languages in every sense.
• A logic programming language is an example of a rule-based language.
• In a rule-based language, rules are specified in no particular order, and the language implementation system must choose an order in which the rules are used to produce the desired result.
• This approach to software development is radically different from those used with the other two categories of languages and clearly requires a completely different kind of language. (Prolog).
• A new category of languages has emerged, the markup/programming hybrid languages. Markup languages are not programming languages.
• For instance, HTML, the most widely used markup language, is used to specify the layout of information in Web documents.
• Programming capability has crept into some extensions to HTML and XML. Among these are the Java Server Pages Standard Tag Library (JSTL) and eXtensible Stylesheet Language Transformations (XSLT).