Assembly languages directly correspond to a machine language (see below) in order to allow machine code instructions to be written in a form understandable by humans. Assembly languages allow programmers to use symbolic addresses which are later converted to absolute addresses by the assembler. Most assemblers also allow for macros and symbolic constants as well.
SSK (Sistema Simvolicheskogo Kodirovaniya, or "System of symbolic coding") for Minsk family of computers.
AKI (AvtoKod Ingenera, i.e., "engineer's autocode") for Minsk family of computers was half-step away from assembly languages and doesn't really fit into any other categories in this article.
Curly-brace languagess are languages whose syntax defines statement blocks using curly-brace characters { and }. All are descended from or strongly influenced by C. Examples of curly-brace languages include:
C (dev ca 1970 by D Ritchie & K Thompson at Bell Labs -- closely associated with the Unix operating system)
Dataflow languages rely on a (usually visual) representation of the flow of data to specify the program. Frequently used for reacting to discrete events or for processing streams of data. Examples of dataflow languages include:
LabView
Max
Pure Data
Data-oriented languages provide powerful ways of searching and manipulating the relations that have been described as entity relationship tables which map one set of things into other sets. Examples of data-oriented languages include:
M (an ANSI standard general purpose language with specializations for database work.)
Data-structured languages are languages whose logic is structured in a way similar to their data. These languages are generally well suited to reflection and introspection. Examples of data-structured languages include:
Lisp, and descendants like Scheme and Tcl. Also TRAC. All use lists as their organizing principle
APL (in which data and code alike are stored and operated on as arrays. By Kenneth Iverson)
It may be argued that assembly languages which statically link data inline with instructions can be considered in this class, albeit in the most primitive way.
In JOY lists are just a special case of quoted programs.
Functional languagess define programs and subroutines as mathematical functions. Many so-called functional languages are "impure" and also contain imperative features. Examples of functional languages include:
Lisp (a very early language based (mostly) on Church's lambda calculus -- By John McCarthy et al at MIT -- very early implementations were interpreted, and had no compiler)
SQL has only a few keywords, and not all the constructs needed for a full programming language
Awk can serve as a prototyping language for C, because the syntax is similar
Logical languagess specify a set of attributes that a solution should have rather then a set of steps to obtain such a solution. Examples of logical languages include:
Prolog which formulates data and the program evaluation mechanism as a special form of mathematical logic known as Horn logic and a general proving mechanism called logical resolution
Machine languages are directly executable by the computer's CPU. It is typically formulated as bit patterns, usually represented in octal or hexadecimal. Each group of npatterns (often 1 or more bytes) caused the circuits in the CPU to execute one of the fundamental operations of the hardware. The activation of specific electrical inputs (eg, CPU package pins for microprocessors), and logical settings for CPU state values, control the processor's computation. Individual machine languages are processor specific and are not portable; they are (essentially) always defined by the CPU developer, not by 3rd parties. The symbolic version, the processor's assembly language, is also -- in most cases -- defined by the developer. Since processors come in families which are based on a shared architecture, the same basic assembly language style can often be used for more than one CPU. Each of the following CPUs served as the basis for a family of processors:
Procedural languagess are based upon the concept of the unit and scope (the data viewing range of an executable code statement). A procedural program is composed of one or more units or modules--either user coded or provided in a code library; each module is composed of one or more procedures, also called a function, routine, subroutine, or method, depending on the programming language. Examples of procedural languages include:
Ada (developed as a result of a DoD initiative to define a standard programming language)
BASIC (BASICs are innocent of most modularity in (especially) versions prior to about 1990)
Object-oriented languagess are languages that support 'data & method' objects. The data structures are defined in object classes, which also include executable code (methods). Thus the effects of a change to the code remain localized. Object classes can be extended by inheritance in most of these languages. Examples of object-oriented languages include:
Java (closely related to C++, but with garbage collection, removal of unsafe features, compilation to universally runnable 'bytecode', protective sandbox for security -- originally from Sun Micro)
Modula-2|modula-3 (data abstraction, information hiding, strong typing, full modularity -- from N Wirth)
Modula-3 (added more object oriented features to Modula-2)
Prototype-based languagess are a special type of object-oriented programming languages, where the distinction between classes and instances have been removed. Examples of prototype-based languages include:
Rule-based languages instantiate rules when activated by conditions in a set of data. Of all possible activations, some set will be selected and the statements belonging to those rules will be executed. Examples of rule-based languages include:
Scripting languages: This term has two apparently diffirent, but in fact similar meanings.
In traditional sense, scripting languages are designed to automate frequently used tasks that usually involve calling or passing commands to external programs.
Many complex aplication programs allow users to implement custom functions by providing them with built-in languages. Those which are ofinterpretive type, are often called scripting languages.
More recently many of these applications have chosen to "build in" traditional scripting languages, such as Perl or Visual BASIC, but there are quite a few "native" scripting languages still in use.
XML-based languagess are languages based on or that operate on XML. Although the big-boy equivalents of oracle/postgresql/mssql don't yet exist for XML, there are languages to navigate through it and its more tree-oriented structure:
Concurrent languages are those that define commands as messages to a process. Processes are collections of message passes. Generally based on the Pi-Calculus, these have had no commercial success.
