EMS Manual

Compiled Filters
EMS Manual—426909-005
5-10
Tokens
Names
Names in the filter language follow the conventions used in TACL, except for length.
Names contain letters, digits, underscores (_), and circumflexes (^), and begin with a
letter. Case is not significant. TACL names can contain up to 31 characters. Names in
the filter language cannot be longer than 30 characters.
Names represent Boolean variables and filter specifications, both of which you must
declare in the filter language.
Names also represent tokens, structures, fields (structure subcomponents), and
subsystem IDs. These names are actually names of TACL variables and must be
defined in TACL. You define most of these names through standard definition files that
you must load. For information on how to load standard definition files, see The Filter
Compiler on page 5-44.
Names that represent constants, such as ZSPI^VAL^TRUE, cannot be used as is. You
must surround such names with brackets, as in [ZSPI^VAL^TRUE]. TACL expands
these bracketed expressions to the values that they represent. ([ZSPI^VAL^TRUE] is
displayed in your source listing as -1, the value of ZSPI^VAL^TRUE.)
Tokens
In a comparison, a token name represents the value of the token. For details, see
Comparisons
on page 5-19. This example compares the value of the header token
ZEMS^TKN^CPU in the current event message to 3:
IF ZEMS^TKN^CPU = 3 THEN PASS;
The current event message passes the filter if the comparison is TRUE.
A token name refers to a parameter token if you so declare it. (For details, see Filter
Parameters on page 5-29.) Otherwise it refers to an event-message token, as in this
example.
To specify a token uniquely, you usually need to specify both the subsystem ID of the
token and the token name. You must do so because the token code that represents
something in subsystem x usually represents something else in subsystem y. (The
subsystem ID is not needed for token codes that are shared by all subsystems, such
as header token-codes.)
For information about the subsystem ID that the language uses when none is
specified, see EMF Default Subsystem ID
on page 5-12.
DESTINATION FILTER OR TRUE
DO IF PASS WHILE
ELSE LIST REQUIRED
EMSTEXTMATCH LITERALLY SSID
Table 5-1. Reserved Words (page 2 of 2) (continued)