Using Caché ObjectScript - InterSystems Documentation

Syntax Rules
In an explicit namespace name, the first character must be a letter or a percent sign (%). The remaining characters must be
letters, numbers, hyphens (–), or underscores (_). The name cannot be longer than 255 characters.
When Caché translates an explicit namespace name to a routine or class name (for example, when creating a cached query
class/routine name), it replaces punctuation characters with lowercase letters, as follows: % = p, _ = u, – = d. An implied
namespace name may contain other punctuation characters; when translating an implied namespace name, these punctuation
characters are replaced by a lowercase "s". Thus the following seven punctuation characters are replaced as follows: @ =
s, : = s, / = s, \ = s, [ = s, ] = s, ^ = s.
When using Caché MultiValue, each MultiValue account is mapped to a Caché namespace. The naming conventions for
MultiValue accounts and Caché namespaces differ. For details about how MultiValue account names are translated to
namespace names, refer to the CREATE.ACCOUNT command in the Caché MultiValue Commands Reference.
For information on using namespaces, see Namespaces and Databases in the Caché Programming Orientation Guide. For
information on creating namespaces, see Configuring Namespaces in the Caché System Administration Guide.
2.8.1 Extended References
An extended reference is a reference to an entity that is located in another namespace. The namespace name can be specified
as a string literal enclosed in quotes, as a variable that resolves to a namespace name, as an implied namespace name, or
as a null string ("") a placeholder that specifies the current namespace. There are three types of extended references:
• Extended Global Reference: references a global variable in another namespace. The following syntactic forms are
supported: ^["namespace"]global and ^|"namespace"|global. For further details, refer to Global Variables
section of the “Variables” chapter of this manual.
• Extended Routine Reference: references a routine in another namespace.
– The DO command, the $TEXT function, and user-defined functions support the following syntactic form:
|"namespace"|routine.
– The JOB command supports the following syntactic forms: routine|"namespace"|,
routine["namespace"], or routine:"namespace".
In all these cases, the extended routine reference is prefaced by a ^ (caret) character to indicate that the specified entity
is a routine (rather than a label or an offset). This caret is not part of the routine name. For example, DO
^|"SAMPLES"|fibonacci invokes the routine named fibonacci, which is located in the SAMPLES namespace.
The command WRITE $$fun^|"SAMPLES"|house invokes the user-defined function fun() in the routine house,
located in the SAMPLES namespace.
• Extended SSVN Reference: references a structured system variable (SSVN) in another namespace. The following
syntactic forms are supported: ^$["namespace"]ssvn and ^$|"namespace"|ssvn. For further details, refer to
the ^$GLOBAL, ^$LOCK, and ^$ROUTINE structured system variables.
All extended references can, of course, specify the current namespace, either explicitly by name, or by specifying a null
string placeholder.
2.9 Reserved Words
There are no reserved words in Caché ObjectScript; you can use any valid identifier as a variable name, function name, or
label. At the same time, it is best to avoid using identifiers that are command names, function names, or other such strings.
Also, since ObjectScript code includes support for embedded SQL, it is prudent to avoid naming any function, object,
variable, or other entity with an SQL reserved word, as this may cause difficulties elsewhere.
14 Using Caché ObjectScript