ABC (programming language)
| ABC | |
|---|---|
| Paradigms | multi-paradigm: imperative, procedural, structured |
| Designed by | Leo Geurts, Lambert Meertens, Steven Pemberton |
| Developer | Centrum Wiskunde & Informatica (CWI) |
| First appeared | January 1987; 38 years ago (1987-01) |
| Stable release | 1.05.02
/ 1990; 35 years ago (1990) |
| Typing discipline | strong, polymorphic |
| OS | Unix-like, Windows, MacOS, and Atari TOS |
| Website | homepages |
| Influenced by | |
| SETL, ALGOL 68 [1] | |
| Influenced | |
| Python | |
ABC is an imperative general-purpose programming language and integrated development environment (IDE) developed at Centrum Wiskunde & Informatica (CWI), in Amsterdam, Netherlands by Leo Geurts, Lambert Meertens, and Steven Pemberton.[2] It is interactive, structured, high-level, and intended to be used instead of BASIC, Pascal, or AWK. It is intended for teaching or prototyping, but not as a systems-programming language.
ABC had a major influence on the design of the language Python, developed by Guido van Rossum, who formerly worked for several years on the ABC system in the mid-1980s.[3] [4]
Features
[edit ]Its designers claim that ABC programs are typically around a quarter the size of the equivalent Pascal or C programs, and more readable.[5] Key features include:
- Only five basic data types
- No required variable declarations
- Explicit support for top-down programming
- Statement nesting is indicated by indentation, via the off-side rule
- Infinite precision arithmetic, unlimited-sized lists and strings, and other features supporting orthogonality and ease of use by novices
- Polymorphic commands and functions
- Interactive environment with command completion, persistent workspaces, and no separate file handling
ABC was originally a monolithic implementation, leading to an inability to adapt to new requirements, such as creating a graphical user interface (GUI). ABC could not directly access the underlying file system and operating system.
The full ABC system includes a programming environment with a structure editor (syntax-directed editor), suggestions, static variables (persistent), and multiple workspaces, and is available as an interpreter–compiler. As of 2020[update] , the latest version is 1.05.02, for Unix, MS-DOS, Atari ST, and MacOS.
Example
[edit ]An example function to collect the set of all words in a document:[6]
HOW TO RETURN words document:
PUT {} IN collection
FOR line IN document:
FOR word IN split line:
IF word not.in collection:
INSERT word IN collection
RETURN collection
Implementations
[edit ]ABC has been through multiple iterations, with the current version being the 4th major release. Implementations exist for Unix-like systems, MS-DOS/Windows, Macintosh, and other platforms. The source code was made available via Usenet in the late 1980s/early 1990s.
References
[edit ]- ^ Biancuzzi, Federico; Warden, Shane (April 2009). Masterminds of Programming: Conversations with the Creators of Major Programming Languages. O'Reilly Media. p. 32. ISBN 978-0-596-51517-1 . Retrieved December 14, 2009.
He [Lambert Meertens] was clearly influenced by ALGOL 68's philosophy of providing constructs that can be combined in many different ways to produce all sorts of different data structures or ways of structuring a program. – Guido van Rossum
- ^ Pemberton, Steven (January 1987). "An Alternative Simple Language and Environment for PCs". IEEE Software. 4 (1): 56–64. doi:10.1109/MS.1987.229797. S2CID 12788361.
- ^ Hamilton, Naomi (2008年05月08日). "The A-Z of Programming Languages: Python". Computerworld. IDG Communications. Archived from the original on 2008年12月29日. Retrieved 2020年09月04日.
... I figured I could design and implement a language 'almost, but not quite, entirely unlike' ABC, improving upon ABC's deficiencies, ...
- ^ Stewart, Bruce (2002年06月04日). "An Interview with Guido van Rossum". ONLamp.com. O’Reilly Media. Archived from the original on 2013年03月13日. Retrieved 2020年09月04日.
... in my head I had analyzed some of the reasons it had failed.
- ^ Pemberton, Steven (2012年02月22日). "The ABC Programming Language: a short introduction". Centrum Wiskunde & Informatica (CWI). Amsterdam. Retrieved 2020年09月04日.
- ^ This article is based on material taken from ABC at the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.
Further reading
[edit ]- Geurts, Leo; Meertens, Lambert; Pemberton, Steven (1990年01月01日). ABC Programmer's Handbook. New York: Prentice Hall. ISBN 0-13-000027-2.