Namespaces
A namespace name may be an explicit namespace name or an implied namespace name. An explicit namespace name is not case-sensitive; regardless of the case of the letters with which it is input, it is always stored and returned in uppercase letters.
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 InterSystems IRIS 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.
The following namespace names are reserved: %SYS, BIN, BROKER, and DOCUMATIC.
When using the InterSystems SQL CREATE DATABASE command, creating an SQL database creates a corresponding InterSystems IRIS namespace.
A namespace exists as a directory in your InterSystems IRIS instance. To return the full pathname of the current namespace, you can invoke the NormalizeDirectory()Opens in a new tab method, as shown in the following example:
WRITE ##class(%Library.File).NormalizeDirectory("")
For information on using namespaces, see Namespaces and Databases. For information on creating namespaces, see Configuring Namespaces.
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:
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Extended Global Reference: references a global variable in another namespace. The following syntactic forms are supported: ^["namespace"]global and ^|"namespace"|global. For further details, see Global Variables.
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Extended Routine Reference: references a routine in another namespace.
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The DO command, the $TEXT function, and user-defined functions support the following syntactic form: |"namespace"|routine.
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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.
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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.
