5.7.5 Context Declarations

     

CMU Common Lisp has a context-sensitive declaration mechanism which is useful because it allows flexible control of the compilation policy in large systems without requiring changes to the source files. The primary use of this feature is to allow the exported interfaces of a system to be compiled more safely than the system internals. The context used is the name being defined and the kind of definition (function, macro, etc.)

The :context-declarations option to  with-compilation-unit (page ) has dynamic scope, affecting all compilation done during the evaluation of the body. The argument to this option should evaluate to a list of lists of the form:

(context-spec declare-form)

In the indicated context, the specified declare forms are inserted at the head of each definition. The declare forms for all contexts that match are appended together, with earlier declarations getting precedence over later ones. A simple example:

:context-declarations
    '((:external (declare (optimize (safety 2)))))

This will cause all functions that are named by external symbols to be compiled with safety 2.

The full syntax of context specs is:

:internal, :external

True if the symbol is internal (external) in its home package.

:uninterned

True if the symbol has no home package.

(:package package-name)

True if the symbol's home package is in any of the named packages (false if uninterned.)

:anonymous

True if the function doesn't have any interesting name (not defmacro, defun, labels or flet).

:macro, :function

:macro is a global (defmacro) macro. :function is anything else.

:local, :global

:local is a labels or flet. :global is anything else.

(:or context-spec)

True when any supplied context-spec is true.

(:and context-spec)

True only when all supplied context-specs are true.

(:not context-spec)

True when context-spec is false.

(:member name)

True when the defined name is one of these names (equal test.)

(:match pattern)

True when any of the patterns is a substring of the name. The name is wrapped with $'s, so ``$FOO'' matches names beginning with ``FOO'', etc.