srfi-29 | chickadee

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Documentation

A Chicken implementation of SRFI 29.

The addition of the escape code ~[n]@* to the SRFI 28 format is not part of this extension.

Conditions

undefined-condition?

undefined-condition? OBJECTprocedure

Is the OBJECT an instance of the SRFI 29 undefined-condition.

A composite-property-condition of (exn srfi-29 undefined).

unbound-variable-condition?

unbound-variable-condition? OBJECTprocedure

Is the OBJECT an instance of the SRFI 29 unbound-variable-condition.

A composite-property-condition of (exn srfi-29 unbound).

Parameters

current-language

current-language #!optional LANGUAGEparameter: Gets or sets the LANGUAGE symbol.

current-country

current-country #!optional COUNTRYparameter: Gets or sets the COUNTRY symbol.

current-locale-details

current-locale-details #!optional LOCALE-DETAILSparameter: Gets or sets the LOCALE-DETAILS list.

current-locale-format-function

current-locale-format-function #!optional FORMAT-PROCEDUREparameter

Gets or sets the FORMAT-PROCEDURE.

This procedure must at least have the signature of a SRFI 28 format procedure. The default is the Chicken extras#format procedure.

reset-locale-parameters

reset-locale-parametersprocedure

When the current-locale is changed (see the locale egg) the current-* parameters need not be set individually. This will update those parameters to the values in the new locale.

Reset as in set anew.

Bundle Operations

A BUNDLE-SPECIFIER is a list of symbols of the form (PACKAGE-NAME [LANGUAGE] [COUNTRY] [DETAILS...]).
A TEMPLATE-NAME is something suitable as a key, such as a symbol or string, but can be any object with a readable printname.
A TEMPLATE-VALUE maybe any object, but should have a readable printname.
A BUNDLE-ALIST is an alist with key TEMPLATE-NAME & value TEMPLATE-VALUE.

So (cons 'template-example 'value-example) is legal, whereas (list 'template-example 'value-example) is not. The form (list 'template-example 'value-example) will have the value (list 'value-example), and not 'value-example, as expected.

declare-bundle!

declare-bundle! BUNDLE-SPECIFIER BUNDLE-ALISTprocedure: Creates a bundle.

undeclare-bundle!

undeclare-bundle! BUNDLE-SPECIFIERprocedure: Removes the bundle specified by BUNDLE-SPECIFIER from the active bundles.

Bundle Database Operations

SRFI 29 does not specify how bundles are stored. This extension uses the filesystem for the bundle database.

Bundles are stored in the system-bundle-directory, unless an ALTERNATE directory is specified.

Within a bundle directory the structure is (directory [LANGUAGE] [COUNTRY] [SCRIPT] [CODESET] [MODIFIER] PACKAGE-NAME).

system-bundle-directory

system-bundle-directory #!optional DIRECTORY-PATHNAMEparameter: Initially DIRECTORY-PATHNAME is (make-pathname (repository-path) "srfi-29-bundles").

Attempts (load-bundle! BUNDLE-SPECIFIER [ALTERNATE]), from most to least specific.

See most-specific-bundle-specifier.

remove-bundle!

remove-bundle! BUNDLE-SPECIFIER #!optional ALTERNATEprocedure

Removes the bundle specified by BUNDLE-SPECIFIER from the active bundles, and from the filesystem.

Will not remove the locale directory hierarchy created by (store-bundle!...).

remove-bundle-directory!

remove-bundle-directory! BUNDLE-SPECIFIER #!optional ALTERNATEprocedure

Removes the bundle directory hierarchy created by (store-bundle!...). Will only remove empty directories. Returns #t if operation succeeded, #f when a non-empty directory encountered.

Does not remove the bundle, if any, from the active bundles. A filesystem only operation.

This procedure should be used with caution.

declared-bundle-specifiers

declared-bundle-specifiersprocedure: Returns a list of all the declared BUNDLE-SPECIFIERs.

declared-bundle-templates

declared-bundle-templates BUNDLE-SPECIFIERprocedure: Returns an alist of all the templates for the BUNDLE-SPECIFIER.

most-specific-bundle-specifier

most-specific-bundle-specifier PACKAGE-NAMEprocedure

Returns the most specific bundle specifier for the current locale.

The current locale is composed of the (current-language), (current-country), and (current-locale-details).

Note that the most-specific-bundle-specifier may not be a declared bundle.

Bundle Template Operations

These routines will use the most specific declared bundle for the package PACKAGE-NAME in the current locale.

required-localized-template

required-localized-template PACKAGE-NAME TEMPLATE-NAMEprocedure: Returns the object for the TEMPLATE-NAME in PACKAGE-NAME. Otherwise a undefined-condition exception is raised.

localized-template

localized-template PACKAGE-NAME TEMPLATE-NAME #!optional PACKAGE-NOT-FOUND TEMPLATE-NOT-FOUNDprocedure

Returns the object for the TEMPLATE-NAME in PACKAGE-NAME. Otherwise the appropriate ...-NOT-FOUND value.

PACKAGE-NOT-FOUND and TEMPLATE-NOT-FOUND have default #t,

localized-template/default

localized-template/default PACKAGE-NAME TEMPLATE-NAME #!optional PACKAGE-NOT-FOUND TEMPLATE-NOT-FOUNDprocedure

Returns (localized-template PACKAGE-NAME TEMPLATE-NAME PACKAGE-NOT-FOUND TEMPLATE-NOT-FOUND).

PACKAGE-NOT-FOUND and TEMPLATE-NOT-FOUND have default TEMPLATE-NAME.

Somewhat like the Posix 'gettext' routine.

make-localized-template

make-localized-template PACKAGE-NAMEprocedure: Returns a localized-template-like procedure curried upon the PACKAGE-NAME.

make-localized-template/default

make-localized-template/default PACKAGE-NAMEprocedure: Returns a localized-template/default-like procedure curried upon the PACKAGE-NAME.

make-required-localized-template

make-required-localized-template PACKAGE-NAMEprocedure: Like make-localized-template but raises an undefined-condition exception should the package or template be missing.

localized-format

localized-format PACKAGE-NAME TEMPLATE-NAME ARG0...procedure

Returns the formatted string using the (current-locale-format-function) and the format string (localized-template PACKAGE-NAME TEMPLATE-NAME) on the arguments ARG0....

When a localized-template is not found and the TEMPLATE-NAME is a string then it is used a the format-string.

A representation is always displayed, even when no template is found. Just not a localized one.

localized-template-set!

localized-template-set! PACKAGE-NAME TEMPLATE-NAME VALUEprocedure

Creates or updates the VALUE for the TEMPLATE-NAME in PACKAGE-NAME and returns #t, when the package exists. Otherwise returns #f.

This can be used to extend the meaning of a package template at runtime. For example: caching the actual closure for a named procedure.

localized-templates

localized-templates PACKAGE-NAMEprocedure: Returns an alist of all the templates for the PACKAGE-NAME.

load-localized-compiled-code

load-localized-compiled-code LIBRARY PACKAGE-NAME TEMPLATE-NAMESprocedure

Loads a Scheme code library and replaces the toplevel variable references from the templates with the actual value. Each item package-name template-name has a variable reference upon entry. Upon exit this is replaced with the variable value after load.

Every item package-name template-name referenced must be defined. Otherwise a (exn srfi-29 undefined) exception if raised.

LIBRARY: absolute-pathname, relative-pathname, or (unitname pathname)
TEMPLATE-NAMES: (list-of template-name).
template-name: (or TEMPLATE-NAME variable-reference).
variable-reference: (or symbol (symbol symbol)).

The corresponding load call for a LIBRARY form is load-relative, load-relative, and load-library. (See Unit eval.)

Notes

(symbol symbol) in variable-reference is a module import reference; this is a brittle feature as it relies upon knowledge of implementation details.
only load-relative is used for a library pathname. Be sure to provide an absolute-pathname when a current-directory relative pathname is needed.
This is an experimental API.

Exceptions

undefined-condition Signaled for unknown bundle-specification, package, template.
unbound-variable-condition Signaled for an unbound reference during localized code resolution.
(exn type) Signaled for argument type errors.
(exn) message = "invalid library load specificiation" arguments = LIBSPEC Signaled during localized code resolution for a bad library load name form.

Thread Local Storage

Just as the locale extension supports per thread locale information so does this extension support per thread bundles. However, localized information is probably accessed more frequently than locale information. So the support for per thread bundles is delayed until runtime. Setting the environment variable SRFI29_TLS to [Yy1] before loading the runtime will activate the feature.

When active each thread may have a different bundle for a package; i.e. a user of srfi-19 can have a different language in each thread.

Usage

(require-extension srfi-29)

Notes

Possible race condition exists creating a bundle file or directory should another thread be performing the same action.
The locale symbols must have a lowercase printname! As such they do not truly reflect ISO 639-1/2 & ISO 3166-1 standard names. This is a SRFI 29 restriction.
(current-locale-details) is ill-defined by the SRFI 29 document. Which symbol means what? This implementation understands:

locale-details: (list SCRIPT CODESET MODIFIER)
SCRIPT: (or symbol #f)
CODESET: (or symbol #f)
MODIFIER: (or symbol #f)

The SRFI 29 document uses the term country for what the locale extension knows as region.

Requirements

miscmacros moremacros lookup-table posix-utils locale check-errors condition-utils

test

setup-helper

Bugs and Limitations

Currently there is no support for source-form code. Such is considered an even worse security-hole than loading compiled code. However, a possibility is use of the sandbox.
store-bundle! does not ensure filemode of 'a+rx' for the created directory tree.

Author

Kon Lovett

Version history

2.5.0: Added dependency on moremacros.
2.4.0: Changed current-locale-format-function to parameter. Documented system-bundle-directory.
2.3.3
2.3.2: Ensures filemode of 'a+rx' for bundles directory.
2.3.1
2.2.0: Added runtime support for package per thread. Removed deprecated identifiers.
2.1.3: Added unbound-variable-condition?. Deprecated !localized-template & make-!localized-template in favor of required-localized-template & make-required-localized-template.
2.1.2
2.1.1
2.1.0: Added undefined-condition?, !localized-template, make-localized-template, make-localized-template/default, load-localized-compiled-code. localized-template & localized-template/default now distinguish an undefined template from an undefined package.
2.0.1: Fixs for bundle-specifier? and load-best-available-bundle!
2.0.0: Intitial Chicken 4 release. Added introspection routines. Removed PORT parameter for localized-format.

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the Software), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED ASIS, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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