2013-10-06

Archive APIs

I'm thinking to make a package system for Sagittarius. For this, I first need archive APIs such as zip and tar. To make things easy for later, I want interface and implementation separated like DBI.

I'm more like go and getter type so making flexible interface from the beginning is not my strong point. So I've checking the other archive library implementations. So far, I've found Java's ZipInputStream/ZipOutputStream seems fine. So current idea would be like this;

;; Interface
(define-class <archive-entry> ()
  ;; might need more
  ((name)
   (size)
   (type)))
;; might not needed
(define-class <archive-input> ()
   ((port)))

(define-class <archive-output> ()
   ((port)))
;; for input
(define-generic next-entry) ;; get entry
;; this should be default method implementation
;; so that subclass can extend.
(define (read-contents input entry)
  ;; returns bytevector read from port.
  ...)

;; for output
(define-generic add-entry) 
If it's possible then it's better to dispatch port type however right now the only way to make custom port is R6RS way and it's always makes the same class object which can't be used for CLOS method dispatcher.

Right now, I need only expander so first try to implement both tar and zip expander I guess.

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