In computer programming

Computer programming

Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...

, a free-form language is a programming language

Programming language

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

 in which the positioning of characters

Character (computing)

In computer and machine-based telecommunications terminology, a character is a unit of information that roughly corresponds to a grapheme, grapheme-like unit, or symbol, such as in an alphabet or syllabary in the written form of a natural language....

 on the page in program text is not significant. Program text does not need to be placed in specific columns as on old punched card

Punched card

A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...

 systems, and frequently ends of lines are not significant. Whitespace is used to delimit tokens, and does not have other significance.

Most free-form languages descend from Algol, including C

C (programming language)

C is a general-purpose computer programming language developed between 1969 and 1973 by Dennis Ritchie at the Bell Telephone Laboratories for use with the Unix operating system....

, Pascal, and Perl

Perl

Perl is a high-level, general-purpose, interpreted, dynamic programming language. Perl was originally developed by Larry Wall in 1987 as a general-purpose Unix scripting language to make report processing easier. Since then, it has undergone many changes and revisions and become widely popular...

. Lisp

Lisp programming language

Lisp is a family of computer programming languages with a long history and a distinctive, fully parenthesized syntax. Originally specified in 1958, Lisp is the second-oldest high-level programming language in widespread use today; only Fortran is older...

 languages are also free-form, although they do not descend from Algol.
REXX

REXX

REXX is an interpreted programming language that was developed at IBM. It is a structured high-level programming language that was designed to be both easy to learn and easy to read...

 is mostly free-form, though in some cases whitespace

Whitespace (computer science)

In computer science, whitespace is any single character or series of characters that represents horizontal or vertical space in typography. When rendered, a whitespace character does not correspond to a visual mark, but typically does occupy an area on a page...

 is a concatenation

Concatenation

In computer programming, string concatenation is the operation of joining two character strings end-to-end. For example, the strings "snow" and "ball" may be concatenated to give "snowball"...

 operator. SQL, though not a full-fledged programming language, is also free-form.

Most free-form languages are also structured programming

Structured programming

Structured programming is a programming paradigm aimed on improving the clarity, quality, and development time of a computer program by making extensive use of subroutines, block structures and for and while loops - in contrast to using simple tests and jumps such as the goto statement which could...

 languages, which is sometimes thought to go along with the free-form syntax: Earlier imperative programming

Imperative programming

In computer science, imperative programming is a programming paradigm that describes computation in terms of statements that change a program state...

 languages such as Fortran 77 used particular columns for line numbers, which many structured languages don't use or need. However, there exist structured languages which are not free-form, such as Python

Python (programming language)

Python is a general-purpose, high-level programming language whose design philosophy emphasizes code readability. Python claims to "[combine] remarkable power with very clear syntax", and its standard library is large and comprehensive...

, in which the indentation level of each line is important.

See also

• Indent style
  Indent style
  In computer programming, an indent style is a convention governing the indentation of blocks of code to convey the program's structure. This article largely addresses the C programming language and its descendants, but can be applied to most other programming languages...
  
  
• Obfuscated code
  Obfuscated code
  Obfuscated code is source or machine code that has been made difficult to understand for humans. Programmers may deliberately obfuscate code to conceal its purpose or its logic to prevent tampering, deter reverse engineering, or as a puzzle or recreational challenge for someone reading the source...
  
  
• Curly bracket programming language - most free-form languages fall within this category
• Off-side rule
  Off-side rule
  A computer programming language is said to adhere to the off-side rule if the scope of declarations in that language is expressed by their indentation. The term and the idea are attributed to Peter J. Landin, and the term can be seen as a pun on the offside law of football .- Definition :Peter J...
  
  - using indentation rather than punctuation to express scope