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Library­Declarations­Cowan

cowan
2013-01-02 05:33:40
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This is a proposal to add further library declarations and import-set types to the large language.

Library declarations

In R7RS it is not an error to provide a library declaration that a specific implementation does not understand, although implementations should provide warnings in such cases. Most of these declarations specified here use "should", which means that implementations are allowed to silently ignore them if they are inappropriate. Furthermore, implementations may (but should not) ignore any list of identifiers. Conflicts between declarations are resolved in an implementation-specific way. Exceptions:

Name control

(reexport import-set ...)

Like import, but also exports all identifiers that were imported. This allows a library to easily extend one or more other libraries.

Optimization

In the list below, importance represents a symbol, one of unimportant (no importance), neutral (some importance, the default), important (substantial importance), or extreme (extreme importance). It is an error to specify anything else.

If no identifiers are named, then the library declaration applies to all defined identifiers.

(speed importance identifier ...)

The named identifiers should be processed so as to maximize execution speed to the extent specified by importance.

(space importance identifier ...)

The named identifiers should be processed so as to minimize the use of space at run time to the extent specified by importance.

(safety importance identifier ...)

The named identifiers should be processed so as to maximize safety at execution time to the extent specified by importance.

(compilation-speed importance identifier ...)

The named identifiers should be processed so as to maximize compilation speed to the extent specified by importance.

(debuggability importance identifier ...)

The named identifiers should be processed so as to maximize ease of debugging to the extent specified by importance.

Compilation

(inline identifier ...)

The procedures named by the identifiers should be inlined by the compiler, if there is one.

(notinline identifier ...)

The procedures named by the identifiers must not be inlined by the compiler, if there is one.

(unused identifier ...)

The implementation should not warn the user if the identifiers are defined but not used in the library.

(verbose identifier ...)

The implementation should process the definitions of the named identifiers (if none are named, the whole library) verbosely.

(terse identifier ...)

The implementation should process the definitions of the named identifiers (if none are named, the whole library) as quietly as is reasonable. The user should still be notified of errors and warnings.

(silent identifier ...)

The implementation should process the definitions of the named identifiers (if none are named, the whole library) silently. The user should still be notified of errors.

Import sets

(drop-prefix import-set identifier)

This import set automatically renames identifiers in the given import-set: any of them which begin with the characters in identifier have those characters removed.

For example, if the library (foo) exports identifiers foo-a, foo-b, and foo-c, then (import (drop-prefix (foo) foo-) will import them under the names of a, b, and c respectively. Chibi Scheme already supports this type of import set.

See also InterfacesCowan.