Pragmats supply information, that does not affect program semantics, to the translator. Some
pragmats are language-defined; all translators are expected to recognize these pragmats (although the
translator is not required to take any action). A translator can also permit additional pragmats to be
A list of pragmats can appear between any two tokens in a program. Certain of the pragmats are
further restricted in where they can appear. The restrictions for each pragmat is given below.
This pragmat is used to inform the translator whether or not to optimize.
If the OPTIMIZE pragmat appears on a scope, it is applied to this scope, and to all scopes nested
within this scope that do not, themselves, specify an OPTIMIZE pragmat.
If the OPTIMIZE pragmat appears on a variable or constant declaration, it controls the
representation for the data item.
If the OPTIMIZE pragmat appears on a type declaration, it applies to the representation of all data
items having that type.
Each of the identifiers must be exceptions. This pragmat indicates that no code need be
generated to check for any of the listed exceptions during elaboration of the scope on which it is
specified. Code will still be generated, however, for the guarded bodies of guard statements which
explicitly handle the listed exceptions. It the exception actually occurs, the effect is undefined.
OPEN and CLOSED
These pragmats are specified on a deferred declaration or on an invocation of a deferred
declaration. On a deferred declaration, they refer to all invocations. On an invocation, they refer to
only that specific invocation. OPEN requests the translator to attempt to compile the invocation open
(inline). CLOSED requests the translator to attempt to compile the invocation closed (out of line).
This pragmat can be specified between any two tokens. LIST(0FF) specifies that the source
listing is not to be printed until the next LIST(0N) pragmat appears.
NONRECURSIVE and NONREENTRANT
These pragmats can be specified on a deferred declaration. They are used to inform the translator
that the deferred declaration will not be invoked recursively (i.e., during its own elaboration) or
reentrantly (simultaneously by two or more activations). If the translator or linker discovers that
these pragmats were wrong, an error will be issued.
This pragmat is used to turn off warning messages issued by the translator when lt discovers that
dangerous aliasing or dangerous sharing will, or might, occur. The 0K(ALIAS) pragmat can appear
either on deferred declarations or an invocations. The OK<(SHARE) pragmat can appear on variable
declarations, constant declarations, and formal parameter definitions.
Placement of Pragmats
Pragmats can appear:
- On a scope. The pragmat must appear immediately before the first token of the scope. For example,
- On a variable declaration, constant declaration, formal parameter definition, or actual parameter.
The pragmat must appear between the last token and the terminating ";" or "," or "/". For example,
- On a deferred declaration. For compound declarations, the pragmat must appear immediately before
the ";" terminating the header. For type and abbreviation declarations, the pragmat must appear
immediately before the terminating ";". For example,