Modula-2+
{{Short description|Programming language}}
{{Infobox programming language
| name = Modula-2+
| logo =
| paradigms = imperative, structured, modular, data and procedure hiding, concurrent
| designers = Paul Rovner, Roy Levin, John Wick
| developer = DEC Systems Research Center (SRC)
Acorn Research Center
| released = {{Start date and age|1984}}
| latest release version =
| latest release date =
| typing = Static, strong, safe
| scope = Lexical
| programming language =
| discontinued = Yes
| platform =
| operating system = Cross-platform
| license = Proprietary
| file ext =
| file format =
| website =
| implementations = DEC SRC Modula-2+, CAMEL (C and Modula Execution Library)
| dialects = DEC SRC
| influenced by = Pascal, ALGOL, Modula-2
| influenced = Modula-3
}}
Modula-2+ is a programming language descended from the Modula-2 language. It was developed at DEC Systems Research Center (SRC) and Acorn Computers Ltd Research Centre in Palo Alto, California. Modula-2+ is Modula-2 with exceptions and threads. The group which developed the language was led by P. Rovner in 1984.{{Cite report |last1=Rovner |first1=Paul |last2=Levin |first2=Roy |last3=Wick |first3=John |date=January 11, 1985 |title=SRC-RR-3 On extending Modula-2 for building large, integrated systems |url=http://www.hpl.hp.com/techreports/Compaq-DEC/SRC-RR-3.html |website=Hewlett-Packard Labs}}
Main differences with Modula-2:
- Concurrency;{{Cite report |last=DeTreville |first=John |date=November 22, 1990 |title=Experience with concurrent garbage collectors for Modula-2+ SRC-RR-64 |url=http://www.hpl.hp.com/techreports/Compaq-DEC/SRC-RR-64.html |website=Hewlett-Packard Labs}} different than the concept of coroutine, which was already part of Modula-2
- Exception handling
- Garbage collection
Implementations
Modula-2+ was used to develop Topaz, an operating system for the SRC DEC Firefly shared memory asymmetric multiprocessing workstation.{{Cite report |last1=Thacker |first1=Charles P. |author1-link=Charles P. Thacker |last2=Stewart |first2=Lawrence C. |last3=Satterthwaite |first3=Edwin H. Jr. |date=December 30, 1987 |title=Firefly: a multiprocessor workstation SRC-RR-23 |url=http://www.hpl.hp.com/techreports/Compaq-DEC/SRC-RR-23.html |website=Hewlett-Packard Labs}} Most Topaz applications were written in Modula-2+, which grew along with the development of the system.{{Cite report |last1=McJones |first1=Paul R. |last2=Swart |first2=Garret F. |date=September 28, 1987 |title=Evolving the Unix system interface to support multithreaded programs SRC-RR-21 |url=http://www.hpl.hp.com/techreports/Compaq-DEC/SRC-RR-21.html |website=Hewlett-Packard Labs}} Modula-2+ was also used by Acorn in the ARX operating system, and to build an integrated development environment in the Acorn Research Center (ARC).{{Cite FTP |last1=Cardelli |first1=Luca |last2=Donahue |first2=James |last3=Glassman |first3=Lucille |last4=Jordan |first4=Mick |last5=Kalsow |first5=Bill |last6=Nelson |first6=Greg |date=November 1989 |server=Hewlett-Packard Labs |url-status=dead |title=Modula-3 Report (revised), Research Report 52, SRC-RR-052 |url=ftp://apotheca.hpl.hp.com/pub/dec/SRC/research-reports/abstracts/src-rr-052.html }} Modula-2+ strongly influenced other languages such as Modula-3, but as of 2005, it had disappeared.
The original developers of Modula-2+ were both acquired: Acorn by Olivetti and Digital Equipment Corporation by Compaq. Compaq was bought by Hewlett-Packard. Olivetti sold the Olivetti Research Center and Olivetti Software Technology Laboratory (after bought Acorn ARC) to Oracle Corporation and was later absorbed by AT&T.{{Cite web |url=http://neil.franklin.ch/Usenet/alt.folklore.computers/20010824_Not_A_RISC_By_Thursday |title=Not a RISC by Thursday |last=Kossow |first=Al |date=August 2001 |website=Newsgroup alt.folklore.computers,comp.sys.acorn.misc}} DEC have made the SRC-reports available to the public.