chickadee » define-structure

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= define-structure

This is a Chicken Scheme egg which implements a QobiScheme-compatible define-structure macro. The resulting object is implemented as a chicken record. It automatically sets up reader syntax for reading and writing the object. It also integrates with the nondeterminism egg, see local-set-{name}-{field}!.


(define-structure name . fields)syntax
(define-public-structure name . fields)syntax
(define-private-structure name . fields)syntax

Creates a new structure. By default all structures are public, generate an export form, making define-structure an alias for define-public-structure.


The following functions are generated when creating a structure.

(make-{name} {field0-value} {field1-value} ...)procedure
(make-keywords-{name} {field-name}: {field-value} ...)procedure

Any fields not defined in make-keywords-{name} will be uninitialized.

? objprocedure

Tests if obj is of a {name} record.

({name}-{field} obj)procedure

Accesses the field.

({name}-{field}-set! obj val)procedure
(set-{name}-{field}! obj val)procedure

The former is created by chicken's define-record, the latter is added for compatbility with QobiScheme.

({name}-{field}-setp! obj proc)procedure
(setp-{name}-{field}! obj proc)procedure

Like set- but calls proc witht he current value and updates it to what proc returns.

(local-set-{name}-{field}! obj val)procedure
(local-setp-{name}-{field}! obj proc)procedure

This set! will be undone when backtracking with the nondeterminism egg.

({name}-{field}-update obj val)procedure
(update-{name}-{field} obj val)procedure
({name}-{field}-updatep obj proc)procedure
(updatep-{name}-{field} obj proc)procedure

like the set and setp versions but these return a new copy of the object.

(set-{name}! obj {field-key}: {field-value} ...)procedure
(setp-{name}! obj {field-key}: {field-value} ...)procedure
(update-{name} obj {field-key}: {field-value} ...)procedure
(updatep-{name} obj {field-key}: {field-value} ...)procedure

As above but with keywords.

(alist->{name} alist)procedure
->alist objprocedure

Convert to and back from an alist.

(old-vector->{name} vector)procedure

Reads in a vector of the form #({case-insensitive-name} {field0} ...). This is only provided for compatibility with Scheme->C. Not yet implemented.


  Copyright (c) 2013, Andrei Barbu, Purdue University
  All rights reserved.
  Contact Andrei Barbu at
  This program is free software: you can redistribute it and/or modify
  it under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation, either version 3 of the License, or
  (at your option) any later version.
  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  GNU Lesser General Public License for more details.
  You should have received a copy of the GNU Lesser General Public License
  along with this program.  If not, see

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