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  ANSI Common Lisp   3 Evaluation and Compilation   3.8 Dictionary Evaluation and Compilation

3.8.19 ignore, ignorable Declaration

Syntax:
(ignore {var | (function fn)}*)

(ignorable {var | (function fn)}*)

Arguments:
var - a variable name.

fn - a function name.

Valid Context:
declaration

Binding Types Affected:
variable, function

Description:
The ignore and ignorable declarations refer to for-value references to variable bindings for the vars and to function bindings for the fns.

An ignore declaration specifies that for-value references to the indicated bindings will not occur within the scope of the declaration. Within the scope of such a declaration, it is desirable for a compiler to issue a warning about the presence of either a for-value reference to any var or fn, or a special declaration for any var.

An ignorable declaration specifies that for-value references to the indicated bindings might or might not occur within the scope of the declaration. Within the scope of such a declaration, it is not desirable for a compiler to issue a warning about the presence or absence of either a for-value reference to any var or fn, or a special declaration for any var.

When not within the scope of a ignore or ignorable declaration, it is desirable for a compiler to issue a warning about any var for which there is neither a for-value reference nor a special declaration, or about any fn for which there is no for-value reference.

Any warning about a "used" or "unused" binding must be of type style-warning, and may not affect program semantics.

The stream variables established by with-open-file, with-open-stream, with-input-from-string, and with-output-to-string, and all iteration variables are, by definition, always "used". Using (declare (ignore v)), for such a variable v has unspecified consequences.

See Also:
declare

Allegro CL Implementation Details:
None.

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