TAL Reference Manual

LITERALs and DEFINEs
TAL Reference Manual—526371-001
5-4
Usage Considerations
identifier
is the identifier of the DEFINE.
param-name
is the identifier of a formal parameter. You can specify up to 31 formal parameters.
An actual parameter can be up to 500 bytes long.
define-body
is all characters between the = and # delimiters. define-body can span multiple
source lines. Enclose character strings in quotation marks ("). To use # in as part of
the
define-body rather than as a delimiter, enclose the # in quotation marks or
embed the # in a character string.
Usage Considerations
DEFINE declarations have the following characteristics:
•
If a DEFINE and a formal parameter have the same identifier, the formal parameter
has priority during expansion.
•
A DEFINE must not reference itself.
•
A DEFINE declaration must not appear within a DEFINE body; that is, do not nest
a DEFINE within a DEFINE.
•
A DEFINE cannot replace a keyword with another term; for example, a DEFINE
cannot replace BEGIN with START.
•
To ensure proper grouping and evaluation of expressions in the DEFINE body, use
parentheses around each DEFINE parameter used in an expression.
•
Within the DEFINE body, place any compound statements within a BEGIN-END
construct.
•
Directives appearing within a DEFINE body are evaluated immediately; they are
not part of the DEFINE itself.
•
If the CODE (DECS) and CODE (RP) statements are equivalent to the DECS and
RP directives but do not execute until a reference to the DEFINE identifier occurs.
Statements are part of the DEFINE itself.