☜	OMI and MUMPS Draft MDC Standard					☞

4 General description
4.1 OMI and M[UMPS]

ANSI/MDC X11.1 defines the components of the M[UMPS] database and operations on them. OMI makes some of these operations, listed here, available over a network. The following references are to the formal definitions in ANSI/MDC X11.1; the additional text is for information only:

• actuallist: 8.1.7 a list of actual arguments passed to a subroutine or process.
• character set profile: Annex A. A character set profile defines 5 attributes of a global or a device: the names of the characters in its character set, the internal codes that represent them, which characters match which pattern codes, which characters may appear in the global name and subscripts, and the collation scheme.
• Close: 8.2.2 relinquishes ownership of a device.
• command: 8.1 The language’s basic unit of execution consists of a verb and arguments on which it operates.
• controlmnemonic: 8.2.29 when used in the argument of a READ or WRITE command, produces a control effect on the device.
• $Data: 7.1.5.3 Function of a gvn indicates whether the variable it names has a value and whether it has descendants.
• $Device: 7.1.4.10 Special variable contains the status of the current device.
• deviceparam: 8.2.2 qualifies a command that applies to a device.
• environment: 7.1.2.4 identifies a specific set of all possible names – a name space. A particular name may appear only once in an environment. Typical implementations place an environment in a directory or a user class, and – with a network – on a node as well.
• expr: 7 a value-producing expression.
• $Get: 7.1.5.7 Function of a gvn returns the value of the variable it names, or the empty string if the variable is not defined.
• gvn: 7.1.2.4 Global variables are persistent data records organized into trees. gvn is the name of a global variable, for example:
  ^INV(5321,"Denver","qu")
  A global variable may optionally have a value, and it may optionally have descendants. A tree of global variables is informally called a "global."
• intexpr: 7.1.4.6 an expr whose value is to be interpreted as an integer.
• Job: 8.2.10 initiates an M[UMPS] process.
• $Job: 7.1.4.10 An unsigned decimal integer uniquely identifies a process on a particular computer.
• $Key: 7.1.4.10 Special variable contains the characters that terminated the last READ command.
• Kill: 8.2.11 deletes a global variable and its descendants.
• label: 6.2.3 identifies a line in an M[UMPS] routine.
• Lock+: 8.2.14 claims exclusive use of an nref or a list of nrefs. If the claim succeeds, other concurrent processes’ claims on those nrefs will not succeed.
• Lock-: 8.2.14 releases a claim on an nref or a list of nrefs.
• Merge: 8.2.15 assigns the value of 1 variable to another and then assigns the values of all the first variable’s descendants to corresponding descendants of the second variable.
• mnemonicspacename: 8.2.17 specifies a set of controlmnemonics and deviceparams to be used with a device.
• mnemonicspec: 8.2.17 a list of mnemonicspacenames.
• naked reference: 7.1.2.4 a shorthand form of gvn referring to the last-used gvn.
• nref: 8.2.14 The objects of database lock operations are organized into trees. Their names are similar to gvns, but they relate to gvns only by an application’s convention. nrefs have no values.
• Open: 8.2.17 gains ownership of a device.
• $Order: 7.1.5.11 Function of a gvn returns the final subscript of the next gvn in a defined tree-walking order.
• processparameters: 8.2.10 qualifies a JOB command.
• $Query: 7.1.5.15 Function of a gvn returns the next gvn in a defined tree-walking order.
• Read: 8.2.19 gets data from a device into a variable.
• routinename: 6 identifies an M[UMPS] routine.
• Set: 8.2.22 creates a global variable and assigns it a value.
• Set $Extract: 8.2.2 creates a global variable and modifies its value by assigning a range of its character positions.
• Set $Piece: 8.2.22 creates a global variable and modifies its value by assigning 1 or more of its pieces.
• ssvn: 7.1.3 A structured system variable begins with "^$" but otherwise has the form of a gvn, for example:
  ^$GLOBAL("INV","CHARACTER")="ASCII"
  states that ^INV uses the ASCII character set profile.
• Use: 8.2.27 directs input and output to a device, making it the current device.
• Write: 8.2.29 puts data from a variable to a device.
• writeargument: 8.2.29 an argument of a WRITE command.
• $X: 7.1.4.10 Special variable contains the current column number for I/O.
• $Y: 7.1.4.10 Special variable contains the current row number for I/O.

B.7 (of this standard, not X11.1) suggests how implementations may combine these basic operations to achieve more complex M[UMPS] operations.

Copyright © Standard Documents; 1977-2024 MUMPS Development Committee;
Copyright © Examples: 1995-2024 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2024 Ed de Moel.

Some specifications are "approved for inclusion in a future standard". Note that the MUMPS Development Committee cannot guarantee that such future standards will indeed be published.

This page most recently updated on 16-Nov-2023, 16:56:40.

For comments, contact Ed de Moel (demoel@jacquardsystems.com)