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....
Health care is the diagnosis, treatment, and prevention of disease, illness, injury, and other physical and mental impairments in humans. Health care is delivered by practitioners in medicine, chiropractic, dentistry, nursing, pharmacy, allied health, and other care providers...
. It was designed for the production of multi-user database
Database
A database is an organized collection of data for one or more purposes, usually in digital form. The data are typically organized to model relevant aspects of reality , in a way that supports processes requiring this information...
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....
and most other popular languages in current usage, and has very different syntax and terminology.
It was largely adopted during the 1970s and early 1980s in healthcare and financial information systems/databases, and continues to be used by many of the same clients today. It is currently used in electronic health record systems as well as by multiple banking networks and online trading/investment services.
History
MUMPS was developed by Neil Pappalardo and colleagues in Dr. Octo Barnett's animal lab at Massachusetts General Hospital (MGH) in Boston
Boston
Boston is the capital of and largest city in Massachusetts, and is one of the oldest cities in the United States. The largest city in New England, Boston is regarded as the unofficial "Capital of New England" for its economic and cultural impact on the entire New England region. The city proper had...
during 1966 and 1967. The original MUMPS system was, like Unix
Unix
Unix is a multitasking, multi-user computer operating system originally developed in 1969 by a group of AT&T employees at Bell Labs, including Ken Thompson, Dennis Ritchie, Brian Kernighan, Douglas McIlroy, and Joe Ossanna...
Digital Equipment Corporation was a major American company in the computer industry and a leading vendor of computer systems, software and peripherals from the 1960s to the 1990s...
The DEC PDP-7 is a minicomputer produced by Digital Equipment Corporation. Introduced in 1965, it was the first to use their Flip-Chip technology. With a cost of only $72,000 USD, it was cheap but powerful by the standards of the time. The PDP-7 was the third of Digital's 18-bit machines, with...
.
Octo Barnett and Neil Pappalardo were also involved with MGH's planning for a Hospital Information System, obtained a backward compatible PDP-9
Programmed Data Processor
Programmed Data Processor was the name of a series of minicomputers made by Digital Equipment Corporation. The name 'PDP' intentionally avoided the use of the term 'computer' because, at the time of the first PDPs, computers had a reputation of being large, complicated, and expensive machines, and...
, and began using MUMPS in the admissions cycle and laboratory test reporting. MUMPS was then an interpreted language
Interpreted language
Interpreted language is a programming language in which programs are 'indirectly' executed by an interpreter program. This can be contrasted with a compiled language which is converted into machine code and then 'directly' executed by the host CPU...
, yet even then, incorporated a hierarchical database file system to standardize interaction with the data. Some aspects of MUMPS can be traced from Rand Corporation's JOSS
JOSS
JOSS was one of the very first interactive, time sharing programming languages.JOSS I, developed by J. Clifford Shaw at RAND was first implemented, in beta form, on the JOHNNIAC computer in May 1963...
BBN Technologies is a high-technology company which provides research and development services. BBN is based next to Fresh Pond in Cambridge, Massachusetts, USA...
TELCOMP was a programming language developed at Bolt, Beranek and Newman in about 1965 and in use until at least 1974.It was an interactive, conversational language based on JOSS, developed by BBN after Cliff Shaw from RAND visited the labs in 1964 as part of the NIH survey...
STRINGCOMP was a programming language developed at Bolt, Beranek and Newman .It was one of the three variants of JOSS II that were developed by BBN. It had extended string handling capabilities to augment JOSS's mathematical focus. It was a strong influence in the development of the programming...
. The MUMPS team deliberately chose to include portability between machines as a design goal. Another feature, not widely supported for machines of the era, in operating system
Operating system
An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...
Hardware is a general term for equipment such as keys, locks, hinges, latches, handles, wire, chains, plumbing supplies, tools, utensils, cutlery and machine parts. Household hardware is typically sold in hardware stores....
In computing, multitasking is a method where multiple tasks, also known as processes, share common processing resources such as a CPU. In the case of a computer with a single CPU, only one task is said to be running at any point in time, meaning that the CPU is actively executing instructions for...
, which was also built into the language itself.
The portability was soon useful, as MUMPS was shortly adapted to a DEC PDP-15, where it lived for some time. MUMPS was developed with the support of a government research grant, and so MUMPS was released to the public domain (no longer a requirement for grants), and was soon ported to a number of other systems including the popular DEC PDP-8
PDP-8
The 12-bit PDP-8 was the first successful commercial minicomputer, produced by Digital Equipment Corporation in the 1960s. DEC introduced it on 22 March 1965, and sold more than 50,000 systems, the most of any computer up to that date. It was the first widely sold computer in the DEC PDP series of...
The Data General Nova was a popular 16-bit minicomputer built by the American company Data General starting in 1969. The Nova was packaged into a single rack mount case and had enough power to do most simple computing tasks. The Nova became popular in science laboratories around the world, and...
The PDP-11 was a series of 16-bit minicomputers sold by Digital Equipment Corporation from 1970 into the 1990s, one of a succession of products in the PDP series. The PDP-11 replaced the PDP-8 in many real-time applications, although both product lines lived in parallel for more than 10 years...
Artronix Incorporated began in 1970 as a project in a computer science class at Washington University School of Medicine in St Louis. The class designed, built and tested a 12-bit minicomputer, which later became the PC12 minicomputer...
PC12 minicomputer. Word about MUMPS spread mostly through the medical community, and by the early 1970s was in widespread use, often being locally modified for their own needs.
By the early 1970s, there were many and varied implementations of MUMPS on a range of hardware platforms. The most widespread was DEC's MUMPS-11 on the PDP-11, and MEDITECH
Meditech
Medical Information Technology, Inc., commonly known as MEDITECH, is a Massachusetts-based software and service company selling information systems, which are installed in health care organizations throughout the world. The company was founded in 1969 by Chairman A. Neil Pappalardo.-Company...
's MIIS. In 1972, many MUMPS users attended a conference which standardized the then-fractured language, and created the MUMPS Users Group and MUMPS Development Committee (MDC) to do so. These efforts proved successful; a standard was complete by 1974, and was approved, on September 15, 1977, as ANSI
American National Standards Institute
The American National Standards Institute is a private non-profit organization that oversees the development of voluntary consensus standards for products, services, processes, systems, and personnel in the United States. The organization also coordinates U.S. standards with international...
standard, X11.1-1977. At about the same time DEC launched DSM-11 (Digital Standard MUMPS) for the PDP-11. This quickly dominated the market, and became the reference implementation of the time.
During the early 1980s several vendors brought MUMPS-based platforms that met the ANSI standard to market. The most significant were Digital Equipment Corporation with DSM (Digital Standard MUMPS), InterSystems
InterSystems
InterSystems Corporation is a privately held vendor of software for high-performance database management, rapid application development, integration, and healthcare information systems...
with ISM (InterSystems M) on VMS and UNIX, and M/11+ on the PDP-11 platform. Other companies developed important MUMPS implementations:
Greystone Technology Corporation with a compiled version called GT.M
GT.M
GT.M is a high-throughput key-value database engine optimized for transaction processing. GT.M is also an application development platform and a compiler for the ISO standard M language, also known as MUMPS.GT.M, an abbreviation for Greystone Technology M, was developed by the Greystone Technology...
DataTree Inc. with an Intel PC based product called DTM
Micronetics Design Corporation with a product line called MSM for UNIX and Intel PC platforms (later ported to IBM's VM operating system, VAX-VMS platforms and Alpha-VMS platforms)
Comp Consultants (later renamed MGlobal), a Houston-based company originally created CCSM on 6800, then 6809 processors, and eventually a port to the 68000, which later became MacMUMPS, a Mac OS
Mac OS
Mac OS is a series of graphical user interface-based operating systems developed by Apple Inc. for their Macintosh line of computer systems. The Macintosh user experience is credited with popularizing the graphical user interface...
based product. They also worked on a the MGM MUMPS implementation. MGlobal also ported their implementation to the DOS platform where it ran as a guest operating system started from DOS.
MGlobal MUMPS was the first commercial MUMPS for the IBM PC and the only Mac implementation. DSM-11 was superseded by VAX/DSM for the VAX/VMS platform, and that was ported to the Alpha
DEC Alpha
Alpha, originally known as Alpha AXP, is a 64-bit reduced instruction set computer instruction set architecture developed by Digital Equipment Corporation , designed to replace the 32-bit VAX complex instruction set computer ISA and its implementations. Alpha was implemented in microprocessors...
in two variants: DSM for OpenVMS, and as DSM for Ultrix.
This period also saw considerable MDC activity. The second revision of the ANSI standard for MUMPS (X11.1-1984) was approved on November 15, 1984. On November 11, 1990 the third revision of the ANSI standard (X11.1-1990) was approved. In 1992 the same standard was also adopted as ISO
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
standard 11756-1992. Use of M as an alternative name for the language was approved around the same time. On December 8, 1995 the fourth revision of the standard (X11.1-1995) was approved by ANSI, and by ISO
International Organization for Standardization
The International Organization for Standardization , widely known as ISO, is an international standard-setting body composed of representatives from various national standards organizations. Founded on February 23, 1947, the organization promulgates worldwide proprietary, industrial and commercial...
Middleware is computer software that connects software components or people and their applications. The software consists of a set of services that allows multiple processes running on one or more machines to interact...
vendor InterSystems had become the dominant player in the MUMPS market with the purchase of several other vendors. Initially they acquired DataTree Inc. in the early 1990s. And, on December 30, 1995, InterSystems acquired the DSM product line from DEC. InterSystems consolidated these products into a single product line, branding them, on several hardware platforms, as OpenM. In 1997, InterSystems essentially completed this consolidation by launching a unified successor named Caché
Caché (software)
InterSystems Caché is a commercial object database management system from InterSystems Corporation. It provides object and SQL access to the database, as well as allowing direct manipulation of Caché’s underlying data structures. The company claims Caché is the world’s fastest object database...
. This was based on their ISM product, but with influences from the other implementations. Micronetics Design Corporation assets were also acquired by InterSystems on June 21, 1998. InterSystems remains today (2011) the dominant MUMPS vendor, selling Caché to MUMPS developers who write applications for a variety of operating systems.
Greystone Technology Corporation's GT.M implementation was sold to Sanchez Computer Associates Inc. (now part of Fidelity National Financial Inc.) in the mid 1990s. On November 7, 2000 Sanchez made GT.M for Linux available under the GPL
GNU General Public License
The GNU General Public License is the most widely used free software license, originally written by Richard Stallman for the GNU Project....
OpenVMS , previously known as VAX-11/VMS, VAX/VMS or VMS, is a computer server operating system that runs on VAX, Alpha and Itanium-based families of computers. Contrary to what its name suggests, OpenVMS is not open source software; however, the source listings are available for purchase...
Tru64 UNIX is a 64-bit UNIX operating system for the Alpha instruction set architecture , currently owned by Hewlett-Packard . Previously, Tru64 UNIX was a product of Compaq, and before that, Digital Equipment Corporation , where it was known as Digital UNIX .As its original name suggests, Tru64...
were also made available under the AGPL license. GT.M continues to be available on other UNIX platforms under a traditional license.
The newest implementation of MUMPS, released in April 2002, is an MSM derivative called M21 from the Real Software Company of Rugby, UK.
There are also several open source implementations of MUMPS, including some research projects. The most notable of these is Mumps/II, by Professor Kevin O'Kane (now at the University of Northern Iowa
University of Northern Iowa
The University of Northern Iowa is a college located in Cedar Falls, Iowa, United States. UNI offers more than 120 majors across the colleges of Business Administration, Education, Humanities and Fine Arts, Natural Sciences, and Social and Behavioral sciences, and graduate college.UNI has...
) and students' project. Dr. O'Kane and Ryan Murphy have also ported the interpreter to Mac OS X.
One of the original creators of the MUMPS language, Neil Pappalardo, early founded a company called MEDITECH. They extended and built on the MUMPS language, naming the new language MIIS (and later, another language named MAGIC). Unlike InterSystems, MEDITECH no longer sells middleware, so MIIS and MAGIC are now only used internally at MEDITECH.
Current users of MUMPS applications
The U.S. Department of Veterans Affairs (formerly the Veterans Administration) was one of the earliest major adopters of the MUMPS language. Their development work (and subsequent contributions to the free MUMPS application codebase) was an influence on many medical users worldwide. In 1995, the Veterans Affairs' patient Admission/Tracking/Discharge system, Decentralized Hospital Computer Program (DHCP) was the recipient of the Computerworld Smithsonian Award
Smithsonian Award
The Computerworld Smithsonian Award is given out annually to individuals who have used technology to produce beneficial changes for society. Nominees are proposed by a group of 100 CEOs of information technology companies...
for best use of Information Technology in Medicine. A decade later (July, 2006), the Department of Veterans Affairs (VA) / Veterans Health Administration (VHA) was the recipient of the Innovations in American Government Award presented by the Ash Institute of the John F. Kennedy School of Government
John F. Kennedy School of Government
The John F. Kennedy School of Government at Harvard University is a public policy and public administration school, and one of Harvard's graduate and professional schools...
Harvard University is a private Ivy League university located in Cambridge, Massachusetts, United States, established in 1636 by the Massachusetts legislature. Harvard is the oldest institution of higher learning in the United States and the first corporation chartered in the country...
for its extension of DHCP into the Veterans Health Information Systems and Technology Architecture (VistA
VistA
The Veterans Health Information Systems and Technology Architecture is an enterprise-wide information system built around an Electronic Health Record , used throughout the United States Department of Veterans Affairs medical system, known as the Veterans Health Administration .It's a collection...
) in July, 2006. Nearly the entire VA hospital system in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
Indian Health Service is an Operating Division within the U.S. Department of Health and Human Services . IHS is responsible for providing medical and public health services to members of federally recognized Tribes and Alaska Natives...
The United States Department of Defense is the U.S...
CHCS hospital system all run systems using MUMPS databases for clinical data tracking.
Large companies currently using MUMPS include AmeriPath (now part of Quest Diagnostics), Care Centric, Epic Systems Corporation
Epic Systems Corporation
Epic Systems Corporation is a privately held health care software company founded in 1979 by Judy Faulkner. Originally headquartered in Madison, Wisconsin, Epic began moving staff to a new $300 million campus in Verona, Wisconsin in late 2005. Nearly all of Epic's staff are based in the greater...
Partners HealthCare is a non-profit organization that owns several hospitals in Massachusetts, primarily in the Boston area. Massachusetts General Hospital and Brigham and Women's Hospital founded the organization in 1994...
GE Healthcare is a division of GE Technology Infrastructure, which is itself a division of General Electric . It employs more than 46,000 people worldwide and is headquartered in Little Chalfont, Buckinghamshire, United Kingdom. GE Healthcare is the first GE business segment to be headquartered...
Centricity is a brand of 31 healthcare IT software solutions from GE Healthcare, a division of General Electric. It includes software for independent physician practices, academic medical centers, hospitals and large integrated delivery networks...
). Many reference laboratories, such as Quest Diagnostics and Dynacare, use MUMPS software written or based on by Antrim Corporation code. Antrim, and its parent Sunquest, was acquired by Misys in 2001.
Coventry Healthcare and Massachusetts Hospital have also been reported to use MUMPS.
MUMPS is also widely used in financial applications. MUMPS gained an early following in the financial sector, and MUMPS applications are in use at many banks and credit unions. It is used by Ameritrade, the largest online trading service in the US with over 12 billion transactions per day, as well as by the Bank of England
Bank of England
The Bank of England is the central bank of the United Kingdom and the model on which most modern central banks have been based. Established in 1694, it is the second oldest central bank in the world...
and Barclays Bank, among others.
The European Space Agency announced on May 13, 2010 that it will use MUMPS (InterSystems Caché) to support the Gaia mission. This mission aims to map the Milky Way
Milky Way
The Milky Way is the galaxy that contains the Solar System. This name derives from its appearance as a dim un-resolved "milky" glowing band arching across the night sky...
with unprecedented precision.
most use of M is either in the form of GT.M or InterSystems Caché. The latter is being aggressively marketed by InterSystems and has had success in penetrating new markets, such as telecommunications, in addition to existing markets.
Overview
MUMPS is a language intended for and designed to build database applications. Secondary language features were included to help programmers make applications using minimal computing resources. The original implementations were interpreted
Interpreter (computing)
In computer science, an interpreter normally means a computer program that executes, i.e. performs, instructions written in a programming language...
, though modern implementations may be fully or partially compiled
Compiler
A compiler is a computer program that transforms source code written in a programming language into another computer language...
. Individual "programs" run in memory "partitions". Early MUMPS memory partitions were limited to 2048 bytes so aggressive abbreviation greatly aided multi-programming on severely resource limited hardware, because more than one MUMPS job could fit into the very small memories extant in hardware at the time. The ability to provide multi-user systems was another language design. The Multi-Programming in the acronym of language name point to this. Even the earliest machines running MUMPS supported multiple jobs running at the same time. With the change from mini-computers to micro-computers a few years later, even a "single user PC" with a single 8-bit CPU with 16K or 64K of memory could support multiple users, running dumb terminals in command line mode. (without any trace of a graphical user interface
Gui
Gui or guee is a generic term to refer to grilled dishes in Korean cuisine. These most commonly have meat or fish as their primary ingredient, but may in some cases also comprise grilled vegetables or other vegetarian ingredients. The term derives from the verb, "gupda" in Korean, which literally...
).
Since memory was tight originally, the language design for MUMPS valued very terse code. Thus, every MUMPS command or function name could be abbreviated from one to three letters in length, e.g. Quit (exit program) as Q, $P = $Piece function, R = Read command, $TR = $Translate function. Spaces and end-of-line markers are significant in MUMPS because line scope promoted the same terse language design. Hence, an entire line of program code could express the same idea a small number of characters that other programming languages might easily take 5 to 10 times as many characters to express. Abbreviation was a common feature of languages designed in this period (e.g., FOCAL-69
FOCAL-69
FOCAL-69 was the landmark version of the FOCAL programming language, more widely publicized than the original version of the language created in 1968...
Tiny BASIC is a dialect of the BASIC programming language that can fit into as little as 2 or 3 KB of memory. This small size made it invaluable in the early days of microcomputers , when typical memory size was only 4–8 KB.- History :...
, etc.). An unfortunate side effect of this coupled with the early need to write minimalist code was that MUMPS programmers routinely did not comment code and used extensive abbreviations, meaning that even an expert MUMPS programmer could not just skim through a page of code to see its function but would have to analyze it line by line.
Database interaction is transparently built into the language. The MUMPS language provides a hierarchical database made up of persistent
Persistence (computer science)
Persistence in computer science refers to the characteristic of state that outlives the process that created it. Without this capability, state would only exist in RAM, and would be lost when this RAM loses power, such as a computer shutdown....
In computer science, a sparse array is an array in which most of the elements have the same value . The occurrence of zero elements in a large array is inconvenient for both computation and storage...
s, which is implicitly "opened" for every MUMPS application. All variable names prefixed with the caret character ("^") use permanent (instead of RAM) storage, will maintain their values after the application exits, and will be visible to (and modifiable by) other running applications. Variables using this shared and permanent storage are called Globals in MUMPS, because the scoping of these variables is "globally available" to all jobs on the system. The more recent and more common use of the name "global variables" in other languages is a more limited scoping of names, coming from the fact that unscoped variables are "globally" available to any programs running in the same process, but not shared among multiple processes. The MUMPS Storage mode (i.e. Globals stored as persistent sparse arrays), gives the MUMPS database the characteristics of a document-oriented database
Document-oriented database
A document-oriented database is a computer program designed for storing, retrieving, and managing document-oriented, or semi structured data, information...
.
All variable names which are not prefixed with caret character ("^") are temporary and private. Like global variables, they also have a hierarchical storage model, but are only "locally available" to a single job, thus they are called "locals". Both "globals" and "locals" can have child nodes (called subscripts in MUMPS terminology). Subscripts are not limited to numerals—any ASCII
ASCII
The American Standard Code for Information Interchange is a character-encoding scheme based on the ordering of the English alphabet. ASCII codes represent text in computers, communications equipment, and other devices that use text...
character or group of characters can be a subscript identifier. While this is not uncommon for modern languages such as Perl or JavaScript, it was a highly unusual feature in the late 1970s. This capability was not universally implemented in MUMPS systems before the 1984 ANSI standard, as only canonically numeric subscripts were required by the standard to be allowed) Thus, the variable named 'Car' can have subscripts "Door", "Steering Wheel" and "Engine", each of which can contain a value and have subscripts of their own. The variable ^Car("Door") could have a nested variable subscript of "Color" for example. Thus, you could say
SET ^Car("Door","Color")="BLUE"
to modify a nested child node of ^Car. In MUMPS terms, "Color" is the 2nd subscript of the variable ^Car (both the names of the child-nodes and the child-nodes themselves are likewise called subscripts). Hierarchical variables are similar to objects with properties in many object oriented
Object-oriented programming
Object-oriented programming is a programming paradigm using "objects" – data structures consisting of data fields and methods together with their interactions – to design applications and computer programs. Programming techniques may include features such as data abstraction,...
languages. Additionally, the MUMPS language design requires that all subscripts of variables are automatically kept in sorted order. Numeric subscripts (including floating-point numbers) are stored from lowest to highest. All non-numeric subscripts are stored in alphabetical order following the numbers. In MUMPS terminology, this is canonical order. By using only non-negative integer subscripts, the MUMPS programmer can emulate the arrays
Array data type
In computer science, an array type is a data type that is meant to describe a collection of elements , each selected by one or more indices that can be computed at run time by the program. Such a collection is usually called an array variable, array value, or simply array...
data type from other languages. Although MUMPS does not natively offer a full set of DBMS
Database management system
A database management system is a software package with computer programs that control the creation, maintenance, and use of a database. It allows organizations to conveniently develop databases for various applications by database administrators and other specialists. A database is an integrated...
features such as mandatory schemas, several DBMS systems have been built on top of it that provide application developers with flat-file, relational and network database features.
Additionally, there are built-in operators which treat a delimited string (e.g., comma-separated values
Comma-separated values
A comma-separated values file stores tabular data in plain-text form. As a result, such a file is easily human-readable ....
) as an array. Early MUMPS programmers would often store a structure of related information as a delimited string, parsing it after it was read in; this saved disk access time and offered considerable speed advantages on some hardware.
MUMPS has no data types. Numbers can be treated as strings of digits, or strings can be treated as numbers by numeric operators (coerced, in MUMPS terminology). Coercion can have some odd side effects, however. For example, when a string is coerced, the parser turns as much of the string (starting from the left) into a number as it can, then discards the rest. Thus the statement IF 20<"30 DUCKS" is evaluated as TRUE in MUMPS.
Other features of the language are intended to help MUMPS applications interact with each other in a multi-user environment. Database locks, process identifiers, and atomicity
Atomicity
In database systems, atomicity is one of the ACID transaction properties. In an atomic transaction, a series of database operations either all occur, or nothing occurs...
of database update transactions are all required of standard MUMPS implementations.
In contrast to languages in the C or Wirth traditions, some space characters between MUMPS statements are significant. A single space separates a command from its argument, and a space, or newline, separates each argument from the next MUMPS token. Commands which take no arguments (e.g., ELSE) require two following spaces. The concept is that one space separates the command from the (nonexistent) argument, the next separates the "argument" from the next command. Newlines are also significant; an IF, ELSE or FOR command processes (or skips) everything else til the end-of-line. To make those statements control multiple lines, you must use the DO command to create a code block.
A "Hello world" program is a computer program that outputs "Hello world" on a display device. Because it is typically one of the simplest programs possible in most programming languages, it is by tradition often used to illustrate to beginners the most basic syntax of a programming language, or to...
in MUMPS might be:
hello
write "Hello, World!",!
quit
and would be run from the MUMPS command line with the command 'do ^hello'. Since MUMPS allows commands to be strung together on the same line, and since commands can be abbreviated to a single letter, this routine could be made more compact:
hello w "Hello, World!",! q
The ',!' after the text generates a newline. The 'quit' is not strictly necessary at the end of a function like this, but is good programming practice in case other functions are added below 'hello' later.
Summary of key language features
The following summary seeks to give programmers familiar with other languages a feeling for what MUMPS is like. This is not a formal language specification, and many features and qualifiers have been omitted for brevity. ANSI X11.1-1995 gives a complete, formal description of the language; an annotated version of this standard is available online.
Data types: There is one universal datatype, which is implicitly coerced
Type conversion
In computer science, type conversion, typecasting, and coercion are different ways of, implicitly or explicitly, changing an entity of one data type into another. This is done to take advantage of certain features of type hierarchies or type representations...
to string, integer, or floating-point datatypes as context requires.
Booleans (called truthvalues in MUMPS): In IF commands and other syntax that has expressions evaluated as conditions, any string value is evaluated as a numeric value, and if that is a nonzero value, then it is interpreted as True. a<b yields 1 if a is less than b, 0 otherwise.
Declarations: None. All variables are dynamically created at the first time a value is assigned.
Lines: are important syntactic entities, unlike their status in languages patterned on C or Pascal. Multiple statements per line are allowed and are common. The scope of any IF, ELSE, and FOR command is "the remainder of current line."
Case sensitivity: Commands and intrinsic functions are case-insensitive. In contrast, variable names and labels are case-sensitive. There is no special meaning for upper vs. lower-case and few widely followed conventions. The percent sign (%) is legal as first character of variables and labels.
Postconditionals: execution of almost all commands can be controlled by following it with a colon and a truthvalue expression. SET:N<10 A="FOO" sets A to "FOO" if N is less than 10; DO:N>100 PRINTERR, performs PRINTERR if N is greater than 100. This construct provides a conditional whose scope is less than a full line.
Abbreviation: You can abbreviate nearly all commands and native functions to one, two, or three characters.
Reserved words: None. Since MUMPS interprets source code by context, there is no need for reserved words. You may use the names of language commands as variables. There has been no contest such as the International Obfuscated C Code Contest
International Obfuscated C Code Contest
The International Obfuscated C Code Contest is a programming contest for the most creatively obfuscated C code. It was held annually between 1984 and 1996, and thereafter in 1998, 2000, 2001, 2004, 2005 and 2006....
for MUMPS, despite the potential of examples such as the following, perfectly legal, MUMPS code:
GREPTHIS
NEW SET,NEW,THEN,IF,KILL,QUIT SET IF="KILL",SET="11",KILL="l1",QUIT="RETURN",THEN="KILL"
IF IF=THEN DO THEN
QUIT:$QUIT QUIT QUIT ; (quit)
THEN IF IF,SET&KILL SET SET=SET+KILL QUIT
MUMPS can be made more obfuscated by using the contracted operator syntax, as shown in this terse example derived from the example above:
GREPTHIS
N S,N,T,I,K,Q S I="K",S="11",K="l1",Q="R",T="K"
I I=T D T
Q:$Q Q Q
T I I,S&K S S=S+K Q
Arrays: are created dynamically, stored as B-trees, are sparse (i.e. use almost no space for missing nodes), can use any number of subscripts, and subscripts can be strings or numeric (including floating point). Arrays are always automatically stored in sorted order, so there is never any occasion to sort, pack, reorder, or otherwise reorganize the database. Built in functions such as $DATA, $ORDER, $NEXT(deprecated) and $QUERY functions provide efficient examination and traversal of the fundamental array structure, on disk or in memory.
for i=10000:1:12345 set sqtable(i)=i*i
set address("Smith","Daniel")="dpbsmith@world.std.com"
Local arrays: variable names not beginning with caret (i.e. "^") are stored in memory by process, are private to the creating process, expire when the creating process terminates. The available storage depends on implementation. For those implementations using partitions, it is limited to the partition size, (A small patition might be 32K). For other implementations, it may be several megabytes.
Global arrays: ^abc, ^def. These are stored on disk, are available to all processes, and are persistent when the creating process terminates. Very large globals (e.g., hundreds of gigabytes) are practical and efficient in most implementations. This is MUMPS' main "database" mechanism. It is used instead of calling on the operating system to create, write, and read files.
Indirection: in many contexts, @VBL can be used, and effectively substitutes the contents of VBL into another MUMPS statement. SET XYZ="ABC" SET @XYZ=123 sets the variable ABC to 123. SET SUBROU="REPORT" DO @SUBROU performs the subroutine named REPORT. This substitution allows for lazy evaluation and late binding as well as effectively the operational equivalent of "pointers" in other languages.
Piece function: This breaks variables into segmented pieces guided by a user specified separator string (sometimes called a "delimiter"). Those who know awk will find this familiar. $PIECE(STRINGVAR,"^",3) means the "third caret-separated piece of STRINGVAR." The piece function can also appear as an assignment (SET command) target. After
SET X="dpbsmith@world.std.com"
$PIECE("world.std.com",".",2) yields "std" SET $P(X,"@",1)="office" causes X to become "office@world.std.com" (note that $P is equivalent to $PIECE and could be written as such).
Order function: This function treats its input as a structure, and finds the next index that exists which has the same structure except for the last subscript. It returns the sorted value that is ordered after the one given as input. (This treats the array reference as a content-addressable data rather than an address of a value)
Set i="" For Set i=$O(stuff(i)) Quit:i="" Write !,i,10,stuff(i)
Here, the argument-less For repeats until stopped by a terminating Quit. This line prints a table of i and stuff(i) where i is successively 6, 10, and 15.
Multi-User/Multi-Tasking/Multi-Processor: MUMPS supports multiple simultaneous users and processes even when the underlying operating system does not (e.g., MS-DOS). Additionally, there is the ability to specify an environment for a variable, such as by specifying a machine name in a variable (as in SET ^|"DENVER"|A(1000)="Foo"), which can allow you to access data on remote machines.
For a thorough listing of the rest of the MUMPS commands, operators, functions and special variables, see these online resources:
MUMPS by Example, or the (out of print) book of the same name by Ed de Moel. Much of the language syntax is detailed there, with examples of usage.
Ansi is a village in Kaarma Parish, Saare County, on the island of Saaremaa, Estonia....
standard.
"MUMPS" vs. "M" naming debate
While of little interest to those outside the MUMPS/M community, this topic has been contentious there.
All of the following positions can, and have been, supported by knowledgeable people at various times:
The language's name became M in 1993 when the M Technology Association adopted it.
The name became M on December 8, 1995 with the approval of ANSI X11.1-1995
Both M and MUMPS are officially accepted names.
M is only an "alternate name" or "nickname" for the language, and MUMPS is still the official name.
Some of the contention arose in response to strong M advocacy on the part of one commercial interest, InterSystems, whose chief executive disliked the name MUMPS and felt that it represented a serious marketing obstacle. Thus, favoring M to some extent became identified as alignment with InterSystems. The dispute also reflected rivalry between organizations (the M Technology Association, the MUMPS Development Committee, the ANSI and ISO Standards Committees) as to who determines the "official" name of the language. Some writers have attempted to defuse the issue by referring to the language as M[UMPS], square brackets being the customary notation for optional syntax elements. A leading authority, and the author of an open source MUMPS implementation, Professor Kevin O'Kane, uses only 'MUMPS'.
The most recent standard (ISO/IEC 11756:1999, re-affirmed on 25 June 2010), still mentions both M and MUMPS as officially accepted names.
Epoch choice
In MUMPS, the current date and time is contained in a special system variable, $H (short for "HOROLOG"). The format is a pair of integers separated by a comma, e.g. "54321,12345" The first number is the number of days since December 31, 1840, i.e. day number 1 is January 1, 1841; the second is the number of seconds since midnight.
James M. Poitras has written that he chose this epoch for the date and time routines in a package developed by his group at MGH in 1969:
(More colorful versions have circulated in the folklore, suggesting, for example, that December 31, 1840 was the exact date of the first entry in the MGH records, but these seem to be urban legends. Another legend is that the date was chosen to commemorate the first use of ether as an anesthetic at Mass General.)
Sample programs
The direct execution of source code on historical computing platforms in an era of tiny disks, minuscule RAM and 300 baud
Baud
In telecommunications and electronics, baud is synonymous to symbols per second or pulses per second. It is the unit of symbol rate, also known as baud rate or modulation rate; the number of distinct symbol changes made to the transmission medium per second in a digitally modulated signal or a...
serial connections led to a historical coding style that was terse, dense and expert friendly, even as contemporary MUMPS coding styles produce more readable code.
First, an example of M code from 2010, a solution to a benchmarking exercise based on calculating the longest sequence encountered when calculating the longest sequence of the Collatz conjecture
Collatz conjecture
The Collatz conjecture is a conjecture in mathematics named after Lothar Collatz, who first proposed it in 1937. The conjecture is also known as the 3n + 1 conjecture, the Ulam conjecture , Kakutani's problem , the Thwaites conjecture , Hasse's algorithm The Collatz conjecture is a...
for a range of integers. This example is written in GT.M and exploits and illustrates many features of MUMPS.
threeen1f
; Find the maximum number of steps for the 3n+1 problem for all integers through two input integers.
; See http://docs.google.com/View?id=dd5f3337_24gcvprmcw
; Assumes input format is 3 integers separated by a space with the first integer smaller than the second.
; The third integer is the number of parallel computation streams. If it is less than twice the
; number of CPUs or cores, the parameter is modified to that value. An optional fourth integer is the
; sizes of blocks of integers on which spawned child processes operate. If it is not specified, the
; block size is approximately the range divided by the number of parallel streams. If the block size is
; larger than the range divided by the number of execution streams, it is reduced to that value.
; No input error checking is done.
; Although the problem can be solved by using strictly integer subscripts and values, this program is
; written to show that the GT.M key-value store can use arbitrary strings for both keys and values -
; each subscript and value is spelled out using the strings in the program source line labelled "digits".
; Furthermore, the strings are in a number of international languages when GT.M is run in UTF-8 mode.
; K.S. Bhaskar 2010612
; No claim of copyright is made with respect to this program.
; Variables do not have to be declared before use, but are New'd in subprograms to ensure that they
; do not conflict with names in the caller.
; The program reads the program source at the label digits to get strings (separated by ;) for each language used.
digits ;zero;eins;deux;tres;quattro;пять;ستة;सात;捌;ஒன்பது
Do digitsinit ; Initialize data for conversion between integers and strings
; Get number of CPUs from /proc/cpuinfo and calculate minimum number of execution streams
Open "cpus":(SHELL="/bin/sh":COMMAND="grep -i ^processor /proc/cpuinfo|wc -l":READONLY)::"PIPE"
Use "cpus" Read streams Use $PRINCIPAL
Close "cpus"
Set streams=2*streams ; At least two execution streams per CPU
; At the top level, the program reads and processes input lines, one at a time. Each line specifies
; one problem to solve. Since the program is designed to resume after a crash and reuse partial
; results computed before the crash, data in the database at the beginning is assumed to be partial
; results from the previous run. After computing and writing results for a line, the database is
; cleared for next line of input or next run of the program.
; Loop for ever, read a line (quit on end of file), process that line
For Read input Quit:$ZEOF!'$Length(input) Do ; input has entire input line
.
. Set i=$Piece(input," ",1) ; i - first number on line is starting integer for the problem
. Set j=$Piece(input," ",2) ; j - second number on line is ending integer for the problem
. Write $FNumber(i,",",0)," ",$FNumber(j,",",0) ; print starting and ending integers, formatting with commas
.
. Set k=$Piece(input," ",3) ; k - third number on input line is number of parallel streams
. If streams>k Do ; print number of execution streams, optionally corrected
.. Write " (",$FNumber(k,",",0)
.. Set k=streams
.. Write "->",$FNumber(k,",",0),")"
. Else Write " ",$FNumber(k,",",0)
.
. Set blk=+$Piece(input," ",4) ; blk - size of blocks of integers is optional fourth piece
. Set tmp=(j-i+k)\k ; default / maximum block size
. If blk&(blk'>tmp) Write " ",$FNumber(blk,",",0) ; print block size, optionally corrected
. Else Do
.. Write " (",$FNumber(blk,",",0)
.. Set blk=tmp
.. Write "->",$FNumber(blk,",",0),")"
.
. ; Define blocks of integers for child processes to work on
. Kill ^limits
. Set tmp=i-1
. For count=1:1 Quit:tmp=j Do
.. Set ^limits(count)=$increment(tmp,blk)
.. Set:tmp>j (tmp,^limits(count))=j
.
. ; Launch jobs. Grab lock l1, atomically increment counter, compute and launch one job for each block of numbers.
. ; Each child job locks l2(pid), decrements the counter and tries to grab lock l1(pid).
. ; When counter is zero, all jobs have started. Parent releases lock l1 and tries to grab lock l2.
. ; When all children have released their l2(pid) locks, they're done and parent can gather & report results.
. Set ^count=0 ; Clear ^count - may have residual value if restarting from crash
. Lock +l1 ; Set lock for process synchronization
. For s=1:1:k Do
.. Set c=$Increment(^count) ; Atomic increment of counter in database for process synchronization
.. Set def=$ZTRNLNM("gtm_tmp") Set:'$Length(def) def=$ZTRNLNM("PWD") ; Working directory for Jobbed process
.. Set err=$Text(+0)_"_"_$Job_"_"_s_".mje" ; STDERR for Jobbed process
.. Set out=$Extract(err,1,$Length(err)-1)_"o" ; STDOUT for Jobbed process
.. Set cmd="doblk(i):(ERROR="""_err_""":OUTPUT="""_out_""":DEFAULT="""_def_""")" ; Command to Job
.. Job @cmd ; Job child process for next block of numbers
. For Quit:'^count Hang 0.1 ; Wait for processes to start (^count goes to 0 when they do)
. Lock -l1 ; Release lock so processes can run
. Set startat=$HOROLOG ; Get starting time
. Lock +l2 ; Wait for processes to finish
.
. ; When parent gets lock l2, child processes have completed and parent gathers and reports results.
. set endat=$HOROLOG ; Get ending time - time between startat and endat is the elapsed time
. ; Calculate duration
. Set duration=(86400*($Piece(endat,",",1)-$Piece(startat,",",1)))+$Piece(endat,",",2)-$Piece(startat,",",2)
. Write " ",$FNumber(^result,",",0) ; Show largest number of steps for the range i through j
. Write " ",$FNumber(^highest,",",0) ; Show the highest number reached during the computation
. Write " ",$FNumber(duration,",",0) ; Show the elapsed time
. Write " ",$FNumber(^updates,",",0) ; Show number of updates
. Write " ",$FNumber(^reads,",",0) ; Show number of reads
. ; If duratation is greater than 0 seconds, display update and read rates
. Write:duration " ",$FNumber(^updates/duration,",",0)," ",$FNumber(^reads/duration,",",0)
. Write !
. Lock -l2 ; Release lock for next run
. Do dbinit ; Initialize database for next run
Quit
digitsinit ; Initialize arrays to convert between strings and integers
New m,x
Set x=$Text(digits)
For m=0:1:9 Set di($Piece(x,";",m+2))=m,ds(m)=$Piece(x,";",m+2)
Quit
inttostr(n) ; Convert an integer to a string
New m,s
Set s=ds($Extract(n,1))
For m=2:1:$Length(n) Set s=s_" "_ds($Extract(n,m))
Quit s
;
strtoint(s) ; Convert a string to an integer
New m,n
Set n=di($Piece(s," ",1))
For m=2:1:$Length(s," ") Set n=10*n+di($Piece(s," ",m))
Quit n
This is where Jobbed processes start
doblk(allfirst)
Set (reads,updates,highest)=0 ; Start with zero reads, writes and highest number
Do digitsinit ; Initialize data for conversion between integers and strings
Lock +l2($JOB) ; Get lock l2 that parent will wait on till this Jobbed processes is done
If $Increment(^count,-1) ; Decrement ^count to say this process is alive
Lock +l1($JOB) ; This process will get lock l1($JOB) only parent has released lock on l1
;
; Process the next block in ^limits that needs processing; quit when done
For Quit:'$Data(^limits($increment(tmp))) Do:1=$increment(^limits(tmp,1)) dostep($select($data(^limits(tmp-1)):^limits(tmp-1)+1,1:allfirst),^limits(tmp))
;
TStart ; Update global statistics inside a transaction
; The following line unconditionally adds the number of reads & write performed by this process to the
; number of reads & writes performed by all processes, and sets the highest for all processes if the
; highest calculated by this process is greater than that calculated so far for all processes
Set:$Increment(^reads,reads)&$Increment(^updates,updates)&(highest>$Get(^highest)) ^highest=highest
TCommit
Lock -l1($JOB),-l2($JOB) ; Release locks to tell parent this parent is done
Quit ; Jobbed processes terminate here
dostep(first,last) ; Calculate the maximum number of steps from first through last
New current,currpath,i,n
For current=first:1:last Do
. Set n=current ; Start n at current
. Kill currpath ; Currpath holds path to 1 for current
. ; Go till we reach 1 or a number with a known number of steps
. For i=0:1 Quit:$Increment(reads)&($Data(^step($$inttostr(n)))!(1=n)) Do
.. Set currpath(i)=n ; log n as current number in sequence
.. Set n=$Select('(n#2):n/2,1:3*n+1) ; compute the next number
.. Set:n>highest highest=n ; see if we have a new highest number reached
. Do:0
.. If 1
.. TStart ; Atomically set maximum
.. Set:i>$Get(^result) ^result=i
.. TCommit
.. Set n="" For Set n=$Order(currpath(n)) Quit:""=n Set:$Increment(updates) ^step($$inttostr(currpath(n)))=$$inttostr(i-n)
Quit
Next, an example of "traditional" M coding style, a VistA source code routine from the late 1970s (last edited in 1992), written originally by George Timson at a time when the language standard had not evolved features such as variable scoping. It is generally recognized that this code is not very readable to many programmers today. Though it should be noted that the code is expert friendly, (i.e. to acculturated VistA programmers it is readable and appropriately structured) - this code is an example of code that has been used effectively for many years. The culture and style of long lived application code cannot and does not change overnight, and when code continues to work, such cultures focus on adding new functionality rather than updating code simply for stylistic reasons.
Due to the terse nature of fully abbreviated MUMPS code, the size of similar code in other programming languages providing the same functionality would be considerably larger.
%DTC
%DTC ; SF/XAK - DATE/TIME OPERATIONS ;1/16/92 11:36 AM
;;19.0;VA FileMan;;Jul 14, 1992
D I 'X1!'X2 S X="" Q
S X=X1 D H S X1=%H,X=X2,X2=%Y+1 D H S X=X1-%H,%Y=%Y+1&X2
K %H,X1,X2 Q
;
C S X=X1 Q:'X D H S %H=%H+X2 D YMD S:$P(X1,".",2) X=X_"."_$P(X1,".",2) K X1,X2 Q
S S %=%#60/100+(%#3600\60)/100+(%\3600)/100 Q
;
H I X<1410000 S %H=0,%Y=-1 Q
S %Y=$E(X,1,3),%M=$E(X,4,5),%D=$E(X,6,7)
S %T=$E(X_0,9,10)*60+$E(X_"000",11,12)*60+$E(X_"00000",13,14)
TOH S %H=%M>2&'(%Y#4)+$P("^31^59^90^120^151^181^212^243^273^304^334","^",%M)+%D
S %='%M!'%D,%Y=%Y-141,%H=%H+(%Y*365)+(%Y\4)-(%Y>59)+%,%Y=$S(%:-1,1:%H+4#7)
K %M,%D,% Q
;
DOW D H S Y=%Y K %H,%Y Q
DW D H S Y=%Y,X=$P("SUN^MON^TUES^WEDNES^THURS^FRI^SATUR","^",Y+1)_"DAY"
S:Y<0 X="" Q
7 S %=%H>21608+%H-.1,%Y=%\365.25+141,%=%#365.25\1
S %D=%+306#(%Y#4=0+365)#153#61#31+1,%M=%-%D\29+1
S X=%Y_"00"+%M_"00"+%D Q
;
YX D YMD S Y=X_% G DD^%DT
YMD D 7 S %=$P(%H,",",2) D S K %D,%M,%Y Q
T F %=1:1 S Y=$E(X,%) Q:"+-"[Y G 1^%DT:$E("TODAY",%)'=Y
S X=$E(X,%+1,99) G PM:Y="" I +X'=X D DMW S X=%
G:'X 1^%DT
PM S @("%H=$H"_Y_X) D TT G 1^%DT:%I(3)'?3N,D^%DT
N F %=2:1 S Y=$E(X,%) Q:"+-"[Y G 1^%DT:$E("NOW",%)'=Y
I Y="" S %H=$H G RT
S X=$E(X,%+1,99)
I X?1.N1"H" S X=X*3600,%H=$H,@("X=$P(%H,"","",2)"_Y_X),%=$S(X<0:-1,1:0)+(X\86400),X=X#86400,%H=$P(%H,",")+%_","_X G RT
D DMW G 1^%DT:'% S @("%H=$H"_Y_%),%H=%H_","_$P($H,",",2)
RT D TT S %=$P(%H,",",2) D S S %=X_% I %DT'["S" S %=+$E(%,1,12)
Q:'$D(%(0)) S Y=% G E^%DT
PF S %H=$H D YMD S %(9)=X,X=%DT["F"*2-1 I @("%I(1)*100+%I(2)"_$E("> <",X+2)_"$E(%(9),4,7)") S %I(3)=%I(3)+X
Q
TT D 7 S %I(1)=%M,%I(2)=%D,%I(3)=%Y K %M,%D,%Y Q
NOW S %H=$H,%H=$S($P(%H,",",2):%H,1:%H-1)
D TT S %=$P(%H,",",2) D S S %=X_$S(%:%,1:.24) Q
DMW S %=$S(X?1.N1"D":+X,X?1.N1"W":X*7,X?1.N1"M":X*30,+X=X:X,1:0)
Q
COMMA ;
S %D=X<0 S:%D X=-X S %=$S($D(X2):+X2,1:2),X=$J(X,1,%),%=$L(X)-3-$E(23456789,%),%L=$S($D(X3):X3,1:12)
F %=%:-3 Q:$E(X,%)="" S X=$E(X,1,%)_","_$E(X,%+1,99)
S:$D(X2) X=$E("$",X2["$")_X S X=$J($E("(",%D)_X_$E(" )",%D+1),%L) K %,%D,%L
Q
HELP S DDH=$S($D(DDH):DDH,1:0),A1="Examples of Valid Dates:" D %
S A1=" JAN 20 1957 or 20 JAN 57 or 1/20/57"_$S(%DT'["N":" or 012057",1:"") D %
S A1=" T (for TODAY), T+1 (for TOMORROW), T+2, T+7, etc." D %
S A1=" T-1 (for YESTERDAY), T-3W (for 3 WEEKS AGO), etc." D %
S A1="If the year is omitted, the computer "_$S(%DT["P":"assumes a date in the PAST.",1:"uses the CURRENT YEAR.") D %
I %DT'["X" S A1="You may omit the precise day, as: JAN, 1957" D %
I %DT'["T",%DT'["R" G 0
S A1="If the date is omitted, the current date is assumed." D %
S A1="Follow the date with a time, such as JAN 20@10, T@10AM, 10:30, etc." D %
S A1="You may enter a time, such as NOON, MIDNIGHT or NOW." D %
I %DT["S" S A1="Seconds may be entered as 10:30:30 or 103030AM." D %
I %DT["R" S A1="Time is REQUIRED in this response." D %
0 Q:'$D(%DT(0))
S A1=" " D % S A1="Enter a date which is "_$S(%DT(0)["-":"less",1:"greater")_" than or equal to " D %
S Y=$S(%DT(0)["-":$P(%DT(0),"-",2),1:%DT(0)) D DD^%DT:Y'["NOW"
I '$D(DDS) W Y,"." K A1 Q
S DDH(DDH,"T")=DDH(DDH,"T")_Y_"." K A1 Q
;
% I '$D(DDS) W !," ",A1 Q
S DDH=DDH+1,DDH(DDH,"T")=" "_A1 Q
The following code is a complete implementation of ROT13
ROT13
ROT13 is a simple substitution cipher used in online forums as a means of hiding spoilers, punchlines, puzzle solutions, and offensive materials from the casual glance. ROT13 has been described as the "Usenet equivalent of a magazine printing the answer to a quiz upside down"...
, a trivially breakable cipher used for various purposes on the Net, not high security. It illustrates the compact nature of MUMPS code and is rather less cryptic than the sample above.
ST ; ROT13 ; Gunter Rensch ; 2000-01-03 ; Encrypt/Decrypt ROT13
Q ; no direct execution
;
; call from your program with
; S A="String"
; S A=$$ROT^ROT13(.A)
;
ROT(R) ;
S S1="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
S S2="NOPQRSTUVWXYZABCDEFGHIJKLM"
S s1="abcdefghijklmnopqrstuvwxyz"
S s2="nopqrstuvwxyzabcdefghijklm"
S R=$TR(R,S1_s1,S2_s2)
Q R
A second implementation is below, which illustrates the possibilities of concision in MUMPS.
s A="String" F i=1:1:$L(A) W $c($S($A($E(A,i))<91:$A($E(A,i))-52#26+65,1:$A($E(A,i))-84#26+97))
Finally, one of the shortest programs ever written in a high-level language, demonstrating the extreme concision of which MUMPS is capable. s x="x x" x x
The same algorithm using expanded variable and command names Set X="Xecute X" Xecute X
This program sets a value of "x x" to a variable named x, and then launches an infinite recursive execution of x, probably resulting in a stack overflow. At just 13 characters, including spaces and an end-of-line mark (since the MUMPS standard specifies storage in characters, not in bytes), using just two characters, the first variant demonstrates that it is also possible to write obscure and obfuscated code in M.
Profile Scripting Language is a superset of MUMPS that adds object-oriented language features.-History:Profile Scripting Language is a language that implements OO concepts such as classes, methods, encapsulation and inheritance as extensions to the MUMPS language...
Caché ObjectScript is a part of the Caché database system sold by Intersystems Corp. The language is a functional superset of the ANSI-standard M programming language. MUMPS programmers can run existing MUMPS routines under Caché with little or no change...
an object oriented extension to MUMPS from a prominent MUMPS vendor
EsiObjects an Open Source Object Oriented extension to MUMPS
Further reading
Walters, Richard (1989). "ABCs of MUMPS. 1989: Butterworth-Heinemann, ISBN 1-55558-017-3.
Walters, Richard (1997). M Programming: A Comprehensive Guide. Digital Press. ISBN 1-55558-167-6.
Lewkowicz, John. The Complete MUMPS : An Introduction and Reference Manual for the MUMPS Programming Language. ISBN 0-13-162125-4
Kirsten, Wolfgang, et al. (2003) Object-Oriented Application Development Using the Caché Postrelational Database ISBN 3-540-00960-4
Martínez de Carvajal Hedrich, Ernesto (1993). "El Lenguaje MUMPS". Completa obra en castellano sobre el lenguaje Mumps. ISBN 84-477-0125-5. Distribuido exclusivamente por su author (ecarvajal@hedrich.es)
O'Kane, K.C.; A language for implementing information retrieval software, Online Review, Vol 16, No 3, pp 127–137 (1992).
O'Kane, K.C.; and McColligan, E. E., A case study of a Mumps intranet patient record, Journal of the Healthcare Information and Management Systems Society, Vol 11, No 3, pp 81–95 (1997).
O'Kane, K.C.; and McColligan, E.E., A Web Based Mumps Virtual Machine, Proceedings of the American Medical Informatics Association 1997
O'Kane, K.C., The Mumps Programming Language, Createspace, ISBN 1438243383, 120 pages (2010).
