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Left Hand Pointer

Input-Transformation

Annotations

Right Hand Pointer

algoref

Introduced in the 1995 ANSI M[UMPS] language standard.

This metalanguage symbol represents the algoritm that will be executed to obtain a certain result. An algorithm is typically a reference to an extrinsic function (potentially using the external calling syntax), occasionally an intrinsic function would be used. In cases where an algorithm specification is required, but no algorithm is currently available, the empty string may be specified instead of the algorithm specification.

emptystring

Introduced in the 1995 ANSI M[UMPS] language standard.

This metalanguage symbol represents an empty string, a string of zero length, written in M[UMPS] as "".

Null string

This term is not one that is formally in any M[UMPS] standard, but it is one that gives rise to a lot of confusion. To many people this term identifies a string that contains no characters, i.e. a string for which $Length(string) equals 0 (zero). On the other hand, many other people use this term to identify a string that contains one character, namely the ASCII character that is called NULL (internal code 0, or $Char(0)).

As a result, many people prefer to avoid using the ambiguous term null string and use the term empty string to denote the string of length 0, and the term NULL character for the string of length 1.

Note that in C and Unix (TM), the length of a string containing one NULL character equals 0, whereas in M[UMPS] $Length($Char(0))=1.

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Copyright © Standard Documents; 1977-2018 MUMPS Development Committee;
Copyright © Examples: 1995-2018 Ed de Moel;
Copyright © Annotations: 2003-2008 Jacquard Systems Research
Copyright © Annotations: 2008-2018 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 28-Nov-2011, 21:33:03 .

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