chickadee » box

box

Documentation

Implements the box data type, both single and multiple valued. A single valued, or core, box is a cell containing a mutable or immutable field. A multiple valued. or values, box is a cell containing a mutable tuple of, 0 or more, values.

The core boxed value maybe any Scheme type, including a variable or a location. The values box will only box Scheme data objects, not a variable or a location.

Box Core

Usage

(import box-core)

Box syntax

The lexical syntax of a box containing the scheme-object S* is #&S*.

Only mutable boxes can be recovered. An immutable, variable, or location box will lose identity when printed.

make-box

(make-box [INITIAL [IMMUTABLE? #f]]) -> boxprocedure

Returns a BOX with, optional, initial value INITIAL.

The BOX is mutable unless the IMMUTABLE? argument is #t.

An attempt to mutate an immutable box will signal an exception.

make-box-mutable

make-box-mutable #!optional INITIALprocedure

Returns a BOX with, optional, initial value INITIAL.

make-box-immutable

make-box-immutable INITIALprocedure

Returns a BOX with an initial value INITIAL.

An attempt to mutate an immutable box will signal an exception.

make-box-variable

(make-box-variable VARIABLE [IMMUTABLE? #f]) -> boxsyntax

Returns a boxed reference to the VARIABLE, which must be in lexical-scope.

The BOX is mutable unless the IMMUTABLE? argument is #t.

An attempt to mutate an immutable box will signal an exception.

make-box-location

(make-box-location TYPE INITIAL-VALUE [IMMUTABLE? #f]) -> boxsyntax

Returns a boxed reference to a location of TYPE and INITIAL-VALUE.

The BOX is mutable unless the IMMUTABLE? argument is #t.

An attempt to mutate an immutable box will signal an exception.

Unavailable in EVALuated source.

box?

box? OBJECTprocedure

Is OBJECT a BOX?

box-mutable?

box-mutable? OBJECTprocedure

Is OBJECT a mutable BOX?

box-immutable?

box-immutable? OBJECTprocedure

Is OBJECT an immutable BOX?

box-variable?

box-variable? OBJECTprocedure

Is OBJECT a boxed variable?

box-location?

box-location? OBJECTprocedure

Is OBJECT a boxed location?

box-set!

box-set! BOX OBJECTprocedure

Changes the boxed value of BOX to OBJECT. Will signal an exception for an immutable {{BOX}.

box-ref

box-ref BOXprocedure

Returns the boxed value of BOX.

box-update!

box-update! BOX FUNCprocedure

Changes the boxed value of BOX to the result of FUNC applied to the current value. Will signal an exception for an immutable {{BOX}.

box-location

(box-location BOX [WEAK? #f]) -> locationprocedure

Returns a LOCATION object for a boxed variable, location or locatable box. Signals an exception otherwise.

The locative is "strong" unless the WEAK? argument is #t. The WEAK? argument is ignored for boxed variables and locations.

The location of a boxed value or boxed location is the box. The location of a boxed variable is the same as (location (box-ref BOX)); currently the location of a symbol may not be taken.

See Locations.

box-swap!

box-swap! BOX FUNC #!optional OBJECT...procedure

Changes the boxed value of BOX to (FUNC <BOX-VALUE> OBJECT...). Will signal an exception for an immutable BOX. Returns the new value of BOX.

make-box-variable-closure

make-box-variable-closure IMMUTABLE? REF SETprocedure
IMMUTABLE?
boolean
REF
(-> *)
SET
(* -> void)

make-box-location-closure

make-box-location-closure IMMUTABLE? REF SET REFLOCprocedure
IMMUTABLE?
boolean
REF
(-> *)
SET
(* -> void)
REFLOC
(-> location)

Box Core Literals

Usage
(import (box-core literals))
Box syntax

An (import (box-core literals)) registers the read-print syntax of a box containing the scheme-object S* as #&S*.

Only mutable boxes can be recovered. An immutable, variable, or location box will lose identity when printed.

Box Values

Usage
(import (box values))
make-box
(make-box [OBJ ...]) -> boxprocedure

Collect 0 or more values in a box.

box?
box? OBJprocedure

A box?

box-ref
box-ref BOXprocedure

Returns 0 or more values from the box.

box-set!
(box-set! BOX [OBJ ...])procedure

Replaces the boxed values with a new tuple of 0 or more values.

box-update!

box-update! BOX FUNCprocedure

Changes the boxed values of BOX to the resulting values of FUNC applied to the current values.

box-arity
box-arity BOXprocedure

Returns the count of boxed values.

box-value-ref
box-value-ref BOX IDXprocedure

Returns the boxed value in the tuple at position IDX.

box-value-set!
box-value-set! BOX IDX OBJprocedure

Replaces the boxed value in the tuple at position IDX with the object OBJ.

Box Values Literals

Usage
(import (box values literals))
Box syntax

An (import (box values literals)) registers the read-print syntax of boxed values as #N&* where N is a length marker and * is either a single value with 0 length or multiple values with a positive length.

SRFI-111

This API is deprecated & will be removed in favor of the srfi-111 egg.

Usage
(import box)

Examples

#;1> (import box-core (box-core literals))
#;2> (define b (make-box 0))
#;3> b
#&0
#;4> (define (inc-box! bx) (set! (box-ref bx) (add1 (box-ref bx))))
#;5> (inc-box! b)
#;6> (box-re b)
1
#;7> (box-swap! b add1)
2
#;8> (box-swap! b * 3)
6f
#;9> (box-ref b)
6

Requirements

test test-utils

Bugs and Limitations

Author

Kon Lovett

Repository

This egg is hosted on the CHICKEN Subversion repository:

https://anonymous@code.call-cc.org/svn/chicken-eggs/release/5/box

If you want to check out the source code repository of this egg and you are not familiar with Subversion, see this page.

Version history

3.9.0
CHICKEN 6 release.

License

Copyright (C) 2009-2026 Kon Lovett. All rights reserved.

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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