《通链参考手册》


Declaration IGNORE, IGNORABLE

●语法设定:

(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

●详情:

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.

●更多信息:

declare


X3J13设计清单非标准部分,可查下面章节:


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