In
computer programming
Computer programming is the process of performing a particular computation (or more generally, accomplishing a specific computing result), usually by designing and building an executable computer program. Programming involves tasks such as ana ...
, a free-form language is a
programming language
A programming language is a system of notation for writing computer programs. Most programming languages are text-based formal languages, but they may also be graphical. They are a kind of computer language.
The description of a programming ...
in which the positioning of
characters
Character or Characters may refer to:
Arts, entertainment, and media Literature
* ''Character'' (novel), a 1936 Dutch novel by Ferdinand Bordewijk
* ''Characters'' (Theophrastus), a classical Greek set of character sketches attributed to The ...
on the page in program text is insignificant. Program text does not need to be placed in specific columns as on old
punched card
A punched card (also punch card or punched-card) is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to di ...
systems, and frequently ends of lines are insignificant.
Whitespace character
In computer programming, whitespace is any character or series of characters that represent horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visible mark, but typically does occupy an area ...
s are used only to delimit
tokens, and have no other significance.
Most free-form languages descend from
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 the ...
, including
C,
Pascal
Pascal, Pascal's or PASCAL may refer to:
People and fictional characters
* Pascal (given name), including a list of people with the name
* Pascal (surname), including a list of people and fictional characters with the name
** Blaise Pascal, Fren ...
, and
Perl
Perl is a family of two high-level, general-purpose, interpreted, dynamic programming languages. "Perl" refers to Perl 5, but from 2000 to 2019 it also referred to its redesigned "sister language", Perl 6, before the latter's name was offici ...
.
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 lisping ...
languages are free-form, although they do not descend from ALGOL.
Rexx
Rexx (Restructured Extended Executor) is a programming language that can be interpreted or compiled. It was developed at IBM by Mike Cowlishaw. It is a structured, high-level programming language designed for ease of learning and reading. ...
is mostly free-form, though in some cases whitespace characters are
concatenation
In formal language, formal language theory and computer programming, string concatenation is the operation of joining character string (computer science), character strings wikt:end-to-end, end-to-end. For example, the concatenation of "sno ...
operators.
SQL, though not a full programming language, is also free-form.
Most free-form languages are also
structured programming
Structured programming is a programming paradigm aimed at improving the clarity, quality, and development time of a computer program by making extensive use of the structured control flow constructs of selection ( if/then/else) and repetition ( ...
languages, which is sometimes thought to go along with the free-form syntax: Earlier
imperative programming
In computer science, imperative programming is a programming paradigm of software that uses statements that change a program's state. In much the same way that the imperative mood in natural languages expresses commands, an imperative program c ...
languages such as
Fortran 77 used particular columns for line numbers, which many structured languages do not use or need.
Structured languages exist which are not free-form, such as
ABC
ABC are the first three letters of the Latin script known as the alphabet.
ABC or abc may also refer to:
Arts, entertainment, and media Broadcasting
* American Broadcasting Company, a commercial U.S. TV broadcaster
** Disney–ABC Television ...
,
Curry
A curry is a dish with a sauce seasoned with spices, mainly associated with South Asian cuisine. In southern India, leaves from the curry tree may be included.
There are many varieties of curry. The choice of spices for each dish in tradit ...
,
Haskell
Haskell () is a general-purpose, statically-typed, purely functional programming language with type inference and lazy evaluation. Designed for teaching, research and industrial applications, Haskell has pioneered a number of programming lan ...
,
Python
Python may refer to:
Snakes
* Pythonidae, a family of nonvenomous snakes found in Africa, Asia, and Australia
** ''Python'' (genus), a genus of Pythonidae found in Africa and Asia
* Python (mythology), a mythical serpent
Computing
* Python (pro ...
and others. Many of these use some variant of the
off-side rule
A computer programming language is said to adhere to the off-side rule of syntax if blocks in that language are expressed by their indentation. The term was coined by Peter Landin, possibly as a pun on the offside rule in association football. ...
, in which indentation, rather than keywords or braces, is used to group blocks of code.
See also
*
Indent style
In computer programming, an indentation style is a convention governing the indentation of blocks of code to convey program structure. This article largely addresses the free-form languages, such as C and its descendants, but can be (and often ...
*
Obfuscated code
In software development, obfuscation is the act of creating source or machine code that is difficult for humans or computers to understand. Like obfuscation in natural language, it may use needlessly roundabout expressions to compose statement ...
*
Curly-bracket programming language Many free-form languages are within this set.
Programming language classification
{{Prog-lang-stub