Introduced in the 1977 ANSI M[UMPS] language standard.
This function returns a code that describes the existence of descendants and values of variables.
Assume that the following elements of Y are defined:
Y(0)=0
Y(1)=1
Y(2)=2
Y(1,2,3)=123
Then the function $DATA will return the following results:
Y(0) has a value and no elements exist with indices like (0,...):
| Reference | Value | |
|---|---|---|
| $DATA(Y(0)) | 1 |
Y(1) has a value and at least one element exists with indices like (1,...), viz. Y(1,2,3):
| Reference | Value | |
|---|---|---|
| $DATA(Y(1)) | 11 |
Y(2) has a value and no elements exist with indices like (2,...):
| Reference | Value | |
|---|---|---|
| $DATA(Y(2)) | 1 |
Y(1,2) has no value, but at least one element exists with indices like (1,2,...), viz. Y(1,2,3):
| Reference | Value | |
|---|---|---|
| $DATA(Y(1,2)) | 10 |
Y(1,2,3) has a value and no elements exist with indices like (1,2,3,...):
| Reference | Value | |
|---|---|---|
| $DATA(Y(1,2,3)) | 1 |
Assume that no local variables exist and that each new example (except for the last) adds a new element to the set.
| Reference | Value | |
|---|---|---|
| Conditions: | Function-values: | |
| Y not defined | $DATA(Y)=0 | |
| SET Y=100 | $DATA(Y)=1 | |
| SET Y="AB" | $DATA(Y)=1 | |
| SET A(1)="ABC" | $DATA(A(1))=1 | |
| $DATA(A)=10 | ||
| SET B(1,2)="BC" | $DATA(B(1,2))=1 | |
| $DATA(B(1))=10 | ||
| $DATA(B))=10 | ||
| SET B(1)="CD" | $DATA(B(1))=11 | |
| KILL B(1,2) | $DATA(B(1,2))=0 | |
| $DATA(B(1))=1 | ||
| $DATA(B)=10 |
$DATA with a global variable as the parameter:
KILL ^A SET ^A(1,2,3)="Value"
Examples with naked references:
| Command | Value of X |
Value of the naked indicator |
|---|---|---|
| SET X=$DATA(^A) | 10 | not defined |
| SET X=$DATA(^(1)) | error | not defined |
| SET X=$DATA(^A(1)) | 10 | "^A(" |
| SET X=$DATA(^A(99)) | 0 | "^A(" |
| SET X=$DATA(^A(1)) | 10 | "^A(" |
| SET X=$DATA(^(1,2)) | 10 | "^A(1," |
| SET X=$DATA(^(2)) | 10 | "^A(1," |
| SET X=$DATA(^(2,3)) | 1 | "^A(1,2," |
| SET X=$DATA(^3)) | 1 | "^A(1,2," |
| SET X=$DATA(^(4)) | 0 | "^A(1,2," |
| SET X=$DATA(^A(1,2)) | 10 | "^A(1," |
| SET ^A(1,2,3,4)="" | "^A(1,2,3," | |
| SET X=$DATA(^A(1,2,3)) | 11 | "^A(1,2," |
$DATA(GLVN)
SET ^ABC(1,2)="reset naked indicator"
; Naked indicator is now ^ABC(1,
SET ^(3,4)=$DATA(^(5,6))
; 1. fetch ^(5,6) = ^ABC(1,5,6)
; 2. store ^(3,4) = ^ABC(1,5,3,4)
; Naked indicator is now: ^ABC(1,5,3,
This document is © Ed de Moel, 1995-2005.
It is part of a book by Ed de Moel that is published under
the title "M[UMPS] by Example" (ISBN 0-918118-42-5).
Printed copies of the book are no longer available.