…cwbowron…

The other day I needed a non-short circuiting or. I thought there might be a SRFI for it, but I looked and couldn’t find one. So I made my own.

This is what I came up with:

(define-syntax complete-or
(syntax-rules ()
((_) #f)
((_ e) e)
[...]

After fiddling with some other code, i realized that I could condense my real code a bit. My finalizers where basically (lambda (value) (finalizer-function value)) where I should just actually pass in finalizer-function

(define/public (play file-index callback)
(let ((file (schemep3-database-index->filename file-index)))
[...]

In VLC backend for schemep3, I have to use what is a fairly common pattern in procedural languages, that doesn’t translate as well into a functional language. It looks something like this:

Var Bar = NULL;
Variable Foo = LibrarySprocketNew();
if ( Foo )
{
Bar = LibrarySprocketBeFancy( Foo );
LibrarySprocketRelease( Foo [...]

As promised in last post, here is an example of playing back an mp3 file using the vlc-ffi code. You may have to change the plugin-path parameter depending on your configuration…

#lang scheme

(require "vlc-ffi.ss")

(define (play-to-end media-player e)
(let loop ()
(let ([state (libvlc_media_player_get_state media-player e)]
[...]