View source for Mary (programming language)

{{more citations needed|date=August 2024}}
{{Infobox programming language
| name =Mary
| logo =
| paradigm = [[Imperative programming|imperative]]
| family = [[ALGOL]]
| developer =[[SINTEF|RUNIT]]
| released = {{Start date and age|1971}}<!-- If known, add |mm|dd|mf=yes -->
| latest_release_version = <!--{{Start date and age|198y|mm|dd|mf=yes}}-->
| latest release date =
| typing = [[static typing|static]], [[strong typing|strong]]
| implementations =
| influenced by = [[ALGOL 68]]
| influenced =
| operating system = [[Cross-platform]]: [[Kongsberg Defence Systems|Kongsberg Våpenfabrikk]] SM-4, [[Norsk Data]] Nord-10/ND-100, Univac-1100 series, [[Norsk Data|ND-100]]/[[Sintran]]-III, [[i386]], [[SPARC]]
| license =
| website =
| file ext =
}}
'''Mary''' is a [[programming language]] designed and implemented by Mark Rain<ref name="van der Meulen"/> at [[SINTEF|RUNIT]] in [[Trondheim]], [[Norway]] during the 1970s. It borrowed many features from [[ALGOL 68]] but was designed for [[systems programming]] (machine-oriented programming), with a subset of operations being reserved for higher-level usage.<ref name="gjessing"/>
 
An unusual feature of its syntax was that expressions were constructed using the conventional [[infix operator]]s, but all of them had the same precedence and evaluation went from left to right unless there were brackets.<ref name="maryassign"/> Assignment had the destination on the right and assignment was considered just another operator.

Similar to [[C (programming language)|C]], several language features appear to have existed to allow producing reasonably well optimised code, despite a quite primitive code generator in the compiler. These included operators similar to the <code>+=</code> ''et alter'' in C and explicit [[Processor register|register]] [[Declaration (computer programming)|declarations]] for [[Variable (computer science)|variables]].

Notable features:
* [[Dataflow]] syntax – values flow from left to right, including assignment
* Expression-based;<ref name="hills"/> most constructs could be used in expressions: blocks, IF, CASE, etc.
* Text-based recursive macros
* Overloaded user-defined operators, not constrained to predefined identifiers as in [[C++]]
* Automatic building and dereferencing of pointers from type context
* Scalar range types
* Array and set enumeration in loop iterators
* Dynamic array descriptors (ROW)

Compilers were made for [[Kongsberg Defence Systems|Kongsberg Våpenfabrikk]]'s SM-4 and [[Norsk Data]] Nord-10/ND-100 mini-computers. The original Mary compiler was written in NU [[ALGOL]], ran on the Univac-1100 series and was used to bootstrap a native compiler for [[Norsk Data|ND-100]]/[[Sintran]]-III. [[SINTEF|RUNIT]] implemented a [[CHILL]] compiler written in Mary which ran on ND-100 and had [[Intel 8086]] and [[Intel 80286|80286]] targets. When this compiler was ported to the [[VAX]] platform, a common backend for Mary and CHILL was implemented. Later, backends for [[i386]] and [[SPARC]] were available. Since the Mary compiler was implemented in Mary, it was possible to run the compiler on all these platforms. An improved version, Mary/2, was developed using a new compiler in the United States.<ref name="mary2"/>

Mary is no longer maintained.

== Example ==

 BEGIN
    INT i := 10;          %% Variable with initial value.
    REF INT ri := i;      %% Pointer initialized to point to i.
    INT j := 11;
    j :- REF INT =: ri;   %% Type conversion and assignment
                          %% ri now points to j.
    i =: (ri :- VAL REF INT);     
                          %% Assignment and type conversion
                          %% ri points to j so j is changed.
    IF j > 10             %% Conditional statement with result
    THEN                  %% used inside an arithmetic expression.
       1
    ELSE
       2
    FI + j =: j;
 END

== See also ==
* [[ALGOL 68]]

==References==
{{FOLDOC}}

{{reflist|refs=
<ref name="mary2">{{cite journal |last1=Rain |first1=Mark |title=The Structure of the MARY/2 Compiler |journal=Software, Practice and Experience |volume=11 |pages=225-235 |publisher=[[Wiley (publisher)|Wiley]] |location=Penobscot Research Center}}</ref>
<ref name="van der Meulen">{{cite journal |last1=van der Meulen |first1=S. G. |title=ALGOL 68 might-have-beens |journal=ACM SIGPLAN Notices |date=June 1977 |volume=12 |issue=6 |pages=1–18 |doi=10.1145/872738.807137}}</ref>
<ref name="maryassign">{{cite journal |last1=Rain |first1=Mark |title=Operation expressions in MARY |journal=ACM SIGPLAN Notices |date=January 1973 |volume=8 |issue=1 |pages=7–14 |doi=10.1145/986925.986927}}</ref>
<ref name="hills">{{cite book |last1=Hills |first1=Michael Turner |last2=Kanō |first2=Sadahiko |title=Programming Electronic Switching Systems: Real-time Aspects and Their Language Implications |date=1976 |publisher=Peregrinus [for] the Institution of Electrical Engineers |isbn=978-0-901223-80-7 |language=en}}</ref>
<ref name="gjessing">{{cite book |last1=Gjessing |first1=Stein |last2=Nygaard |first2=Kristen |title=ECOOP '88 European Conference on Object-Oriented Programming: Oslo, Norway, August 15-17, 1988. Proceedings |date=1988 |publisher=Springer Science & Business Media |isbn=978-3-540-50053-7 |language=en}}</ref>
}}

==Further reading==
* {{cite book |last1=Conradi |first1=Reidar |last2=Holager |first2=Per |title=MARY Textbook |date=1974 |publisher=RUNIT |isbn=978-82-595-0403-6 |language=en}}

{{ALGOL programming}}

[[Category:ALGOL 68 dialect]]
[[Category:Norsk Data software]]
[[Category:Kongsberg Gruppen]]