In
computer science
Computer science is the study of computation, automation, and information. Computer science spans theoretical disciplines (such as algorithms, theory of computation, information theory, and automation) to practical disciplines (includin ...
, a high-level programming language is a
programming language with strong
abstraction from the details of the
computer. In contrast to
low-level programming languages, it may use
natural language ''elements'', be easier to use, or may automate (or even hide entirely) significant areas of computing systems (e.g.
memory management), making the process of developing a program simpler and more understandable than when using a lower-level language. The amount of abstraction provided defines how "high-level" a programming language is.
In the 1960s, a high-level programming language using a
compiler
In computing, a compiler is a computer program that translates computer code written in one programming language (the ''source'' language) into another language (the ''target'' language). The name "compiler" is primarily used for programs that ...
was commonly called an ''
autocode''.
Examples of autocodes are
COBOL and
Fortran.
The first high-level programming language designed for computers was
Plankalkül, created by
Konrad Zuse. However, it was not implemented in his time, and his original contributions were largely isolated from other developments due to
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
, aside from the language's influence on the "Superplan" language by
Heinz Rutishauser and also to some degree
ALGOL
ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by th ...
. The first significantly widespread high-level language was
Fortran, a machine-independent development of IBM's earlier
Autocode systems. The
ALGOL
ALGOL (; short for "Algorithmic Language") is a family of imperative computer programming languages originally developed in 1958. ALGOL heavily influenced many other languages and was the standard method for algorithm description used by th ...
family, with
ALGOL 58 defined in 1958 and
ALGOL 60 defined in 1960 by committees of European and American computer scientists, introduced
recursion as well as
nested functions under
lexical scope. ALGOL 60 was also the first language with a clear distinction between
value and
name-parameters and their corresponding
semantics. ALGOL also introduced several
structured programming concepts, such as the
while-do
and
if-then-else
constructs and its
syntax was the first to be described in formal notation – ''
Backus–Naur form'' (BNF). During roughly the same period,
COBOL introduced
record
A record, recording or records may refer to:
An item or collection of data Computing
* Record (computer science), a data structure
** Record, or row (database), a set of fields in a database related to one entity
** Boot sector or boot record, ...
s (also called structs) and
Lisp
A lisp is a speech impairment in which a person misarticulates sibilants (, , , , , , , ). These misarticulations often result in unclear speech.
Types
* A frontal lisp occurs when the tongue is placed anterior to the target. Interdental lispi ...
introduced a fully general
lambda abstraction in a programming language for the first time.
Features
"High-level language" refers to the higher level of abstraction from
machine language. Rather than dealing with registers, memory addresses, and call stacks, high-level languages deal with variables, arrays,
objects, complex arithmetic or boolean expressions, subroutines and functions, loops,
thread
Thread may refer to:
Objects
* Thread (yarn), a kind of thin yarn used for sewing
** Thread (unit of measurement), a cotton yarn measure
* Screw thread, a helical ridge on a cylindrical fastener
Arts and entertainment
* ''Thread'' (film), 2016 ...
s, locks, and other abstract computer science concepts, with a focus on
usability over optimal program efficiency. Unlike low-level
assembly languages, high-level languages have few, if any, language elements that translate directly into a machine's native
opcodes. Other features, such as string handling routines, object-oriented language features, and file input/output, may also be present. One thing to note about high-level programming languages is that these languages allow the programmer to be detached and separated from the machine. That is, unlike low-level languages like assembly or machine language, high-level programming can amplify the programmer's instructions and trigger a lot of data movements in the background without their knowledge. The responsibility and power of executing instructions have been handed over to the machine from the programmer.
Abstraction penalty
High-level languages intend to provide features that standardize common tasks, permit rich debugging, and maintain architectural agnosticism; while low-level languages often produce more efficient code through
optimization for a specific system architecture. ''Abstraction penalty'' is the cost that high-level programming techniques pay for being unable to optimize performance or use certain hardware because they don't take advantage of certain low-level architectural resources. High-level programming exhibits features like more generic data structures and operations, run-time interpretation, and intermediate code files; which often result in execution of far more operations than necessary, higher memory consumption, and larger binary program size. For this reason, code which needs to run particularly quickly and efficiently may require the use of a lower-level language, even if a higher-level language would make the coding easier. In many cases, critical portions of a program mostly in a high-level language can be hand-coded in
assembly language, leading to a much faster, more efficient, or simply reliably functioning
optimised program.
However, with the growing complexity of modern
microprocessor
A microprocessor is a computer processor where the data processing logic and control is included on a single integrated circuit, or a small number of integrated circuits. The microprocessor contains the arithmetic, logic, and control circu ...
architectures, well-designed compilers for high-level languages frequently produce code comparable in efficiency to what most low-level programmers can produce by hand, and the higher abstraction may allow for more powerful techniques providing better overall results than their low-level counterparts in particular settings.
High-level languages are designed independent of a specific computing system architecture. This facilitates executing a program written in such a language on any computing system with compatible support for the Interpreted or
JIT program. High-level languages can be improved as their designers develop improvements. In other cases, new high-level languages evolve from one or more others with the goal of aggregating the most popular constructs with new or improved features. An example of this is
Scala which maintains backward compatibility with
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
which means that programs and libraries written in Java will continue to be usable even if a programming shop switches to Scala; this makes the transition easier and the lifespan of such high-level coding indefinite. In contrast, low-level programs rarely survive beyond the system architecture which they were written for without major revision. This is the engineering 'trade-off' for the 'Abstraction Penalty'.
Relative meaning
Examples of high-level programming languages in active use today include
Python,
JavaScript
JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of Website, websites use JavaScript on the Client (computing), client side ...
,
Visual Basic,
Delphi,
Perl
Perl is a family of two High-level programming language, high-level, General-purpose programming language, general-purpose, Interpreter (computing), interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it ...
,
PHP,
ECMAScript,
Ruby
A ruby is a pinkish red to blood-red colored gemstone, a variety of the mineral corundum (aluminium oxide). Ruby is one of the most popular traditional jewelry gems and is very durable. Other varieties of gem-quality corundum are called sapp ...
,
C#,
Java
Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...
and many others.
The terms ''high-level'' and ''low-level'' are inherently relative. Some decades ago, the
C language, and similar languages, were most often considered "high-level", as it supported concepts such as expression evaluation,
parameterised recursive functions, and data types and structures, while
assembly language was considered "low-level". Today, many programmers might refer to C as low-level, as it lacks a large
runtime-system (no garbage collection, etc.), basically supports only scalar operations, and provides direct memory addressing. It, therefore, readily blends with assembly language and the machine level of
CPU
A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, and ...
s and
microcontrollers. Also, in the introduction chapter of
The C Programming Language
''The C Programming Language'' (sometimes termed ''K&R'', after its authors' initials) is a computer programming book written by Brian Kernighan and Dennis Ritchie, the latter of whom originally designed and implemented the language, as well as ...
(second edition) by K&R, C is considered as a relatively "low level" language.
Assembly language may itself be regarded as a higher level (but often still one-to-one if used without
macro
Macro (or MACRO) may refer to:
Science and technology
* Macroscopic, subjects visible to the eye
* Macro photography, a type of close-up photography
* Image macro, a picture with text superimposed
* Monopole, Astrophysics and Cosmic Ray Observat ...
s) representation of
machine code, as it supports concepts such as constants and (limited) expressions, sometimes even variables, procedures, and
data structures.
Machine code, in its turn, is inherently at a slightly higher level than the
microcode or
micro-operations used internally in many processors.
Execution modes
There are three general modes of execution for modern high-level languages:
; Interpreted: When code written in a language is
interpreted, its syntax is read and then executed directly, with no compilation stage. A program called an ''interpreter'' reads each program statement, following the program flow, then decides what to do, and does it. A hybrid of an interpreter and a compiler will compile the statement into machine code and execute that; the machine code is then discarded, to be interpreted anew if the line is executed again. Interpreters are commonly the simplest implementations of the behavior of a language, compared to the other two variants listed here.
; Compiled: When code written in a language is
compiled, its syntax is transformed into an executable form before running. There are two types of compilation:
:; Machine code generation: Some compilers compile source code directly into
machine code. This is the original mode of compilation, and languages that are directly and completely transformed to machine-native code in this way may be called ''truly compiled'' languages. See
assembly language.
:; Intermediate representations: When code written in a language is compiled to an
intermediate representation, that representation can be optimized or saved for later execution without the need to re-read the source file. When the intermediate representation is saved, it may be in a form such as
bytecode
Bytecode (also called portable code or p-code) is a form of instruction set designed for efficient execution by a software interpreter. Unlike human-readable source code, bytecodes are compact numeric codes, constants, and references (norma ...
. The intermediate representation must then be interpreted or further compiled to execute it.
Virtual machines that execute bytecode directly or transform it further into machine code have blurred the once clear distinction between intermediate representations and truly compiled languages.
; Source-to-source translated or transcompiled: Code written in a language may be translated into terms of a lower-level language for which native code compilers are already common.
JavaScript
JavaScript (), often abbreviated as JS, is a programming language that is one of the core technologies of the World Wide Web, alongside HTML and CSS. As of 2022, 98% of Website, websites use JavaScript on the Client (computing), client side ...
and the language
C are common targets for such translators. See
CoffeeScript,
Chicken
The chicken (''Gallus gallus domesticus'') is a domestication, domesticated junglefowl species, with attributes of wild species such as the grey junglefowl, grey and the Ceylon junglefowl that are originally from Southeastern Asia. Rooster ...
Scheme, and
Eiffel as examples. Specifically, the generated C and C++ code can be seen (as generated from the Eiffel language when using the
EiffelStudio IDE) in the EIFGENs directory of any compiled Eiffel project. In Eiffel, the ''translated'' process is referred to as transcompiling or transcompiled, and the Eiffel compiler as a transcompiler or
source-to-source compiler.
Note that languages are not strictly ''interpreted'' languages or ''compiled'' languages. Rather, implementations of language behavior use interpreting or compiling. For example,
ALGOL 60 and
Fortran have both been interpreted (even though they were more typically compiled). Similarly, Java shows the difficulty of trying to apply these labels to languages, rather than to implementations; Java is compiled to bytecode which is then executed by either interpreting (in a
Java virtual machine (JVM)) or compiling (typically with a just-in-time compiler such as
HotSpot
Hotspot, Hot Spot or Hot spot may refer to:
Places
* Hot Spot, Kentucky, a community in the United States
Arts, entertainment, and media Fictional entities
* Hot Spot (comics), a name for the DC Comics character Isaiah Crockett
* Hot Spot (Tra ...
, again in a JVM). Moreover, compiling, transcompiling, and interpreting is not strictly limited to only a description of the compiler artifact (binary executable or IL assembly).
High-level language computer architecture
Alternatively, it is possible for a high-level language to be directly implemented by a computer – the computer directly executes the HLL code. This is known as a ''
high-level language computer architecture'' – the
computer architecture
In computer engineering, computer architecture is a description of the structure of a computer system made from component parts. It can sometimes be a high-level description that ignores details of the implementation. At a more detailed level, the ...
itself is designed to be targeted by a specific high-level language. The
Burroughs large systems were target machines for
ALGOL 60, for example.
See also
*
Abstraction (computer science)
*
Generational list of programming languages
*
Low-level programming languages
*
High-level assembler
*
Very high-level programming languages
*
Categorical list of programming languages
Notes
References
External links
* http://c2.com/cgi/wiki?HighLevelLanguage - The
WikiWikiWeb's article on high-level programming languages
{{DEFAULTSORT:High-Level Programming Language
Programming language classification