Introduction

Section 1 consists of nine clauses that describe the MUMPS language. Clause 1 describes the metalanguage used in the remainder of Section 1 for the static syntax. The remaining clauses describe the static syntax and overall semantics of the language. The distinction between "static" and "dynamic" syntax is as follows. The static syntax describes the sequence of characters in a routine as it appears on a tape in routine interchange or on a listing. The dynamic syntax describes the sequence of characters that would be encountered by an interpreter during execution of the routine. (There is no requirement that MUMPS actually be interpreted). The dynamic syntax takes into account transfers of control and values produced by indirection.

Clauses 10 through 21 highlight, for the benefit of implementors and application programmers, aspects of the language that must be accorded special attention if M program transferability (i.e., portability of source code between various M implementations) is to be achieved. It provides a specification of limits that must be observed by both implementors and programmers if portability is not to be ruled out. To this end, implementors must meet or exceed these limits, treating them as a minimum requirement. Any implementor who provides definitions in currently undefined areas must take into account that this action risks jeopardizing the upward compatibility of the implementation, upon subsequent revision of the M Language Specification. Application programmers striving to develop portable programs must take into account the danger of employing "unilateral extensions" to the language made available by the implementor.

The following definitions apply to the use of the terms explicit limit and implicit limit within this document. An explicit limit is one which applies directly to a referenced language construct. Implicit limits on language constructs are second-order effects resulting from explicit limits on other language constructs. For example, the explicit command line length restriction places an implicit limit on the length of any construct which must be expressed entirely within a single command line.

Clauses 22 through 24 describe the binding between M and ANSI X3.64. ANSI X3.64 is a functional standard for additional control functions for data interchange with twodimensional character-imaging input and/or output devices. It is an ANSI standard, but also an ISO standard with roughly similar characteristics exists (ISO 2022). As such, it has been implemented in many devices worldwide. It is expected that M can be easily adapted to these implementations.

The standard defined as ANSI X3.64 defines a format for device-control. No physical device is required to be able to perform all possible control-functions. In reality, as some functions rely on certain physical properties of specific devices, no device will be able to perform all functions. The standard, however, does not specify which functions a device should be able to do, but if it is able to perform a function, how the control-information for this function is to be specified.

This binding is to the functional definitions included in X3.64. The actual dialogue between the M implementation and the device is left to the implementor.

BS ISO/IEC 11756:1999

Information technology. Programming languages. M

Current, Under Review

Published:

15 Nov 1999