New Scheme "abcddb-tool"

Script to parse the xmcd files generated by the musicbrainz
tool. Since you already can't submit these to freedb, there's no
reason not to add support for separate ARIST/TITLE, multiple GENREs,
and vorbis/flac specific track tags (e.g. PART, ISRC). Currently only
implements a trivial database.

diff --git a/abcddb-tool b/abcddb-tool
new file mode 100755 (executable)
index 0000000..8aab4ed
--- /dev/null
+++ b/abcddb-tool
@@ -0,0 +1,95 @@
+#!/usr/bin/guile -s
+!#
+
+;;; -*- scheme -*-
+
+;;; Parse for enhanced XMCD. Original format: http://ftp.freedb.org/pub/freedb/latest/DBFORMAT
+
+(use-modules (ice-9 format)
+            (ice-9 rdelim)
+            (ice-9 streams)
+            (ice-9 regex)
+            (ice-9 vlist)
+
+            (srfi srfi-1))
+
+;;; VList/VHash utility functions
+
+(define (vhash-cat key new-value vhash)
+  "Add NEW-VALUE to the VList stored under VHASH.KEY"
+  (vhash-set key (vlist-append (let ((lst (vhash-assoc key vhash)))
+                                 (if lst (cdr lst) vlist-null))
+                               (vlist-cons new-value vlist-null))
+             vhash))
+
+(define (vhash-set key new-value vhash)
+  (vhash-cons key new-value (vhash-delete key vhash)))
+
+
+;;; Simple key/value database for cddb and toc info
+
+;;; DO NOT RELY ON THE IMPLEMENTATION, it sucks. Always use the query
+;;; functions. The disc query functions return the list of values, the
+;;; track query functions return an alist of (track-num
+;;; . values). Values are always plural, just grab the car if you want
+;;; a single value. It's not the best interface, but it sure beats
+;;; grepping the xmcd file!
+
+(define (make-initial-db . toplevel-keys)
+  (fold (lambda (key db) (vhash-cons key vlist-null db)) vlist-null toplevel-keys))
+
+(define (cddb-query-disc db tag)
+  "Query the database for a disc attribute"
+  (let ((result (vhash-assoc tag (cdr (vhash-assoc 'disc db)))))
+    (if result (vlist->list (cdr result)) #f)))
+
+(define (cddb-query-tracks db tag)
+  "Query the database for a track attribute and return alist
+of (disc-number . tag-value)"
+  (let ((r (vlist->list (vhash-fold (lambda (key vh results)
+                                     (let ((result (vhash-assoc tag vh)))
+                                       (if result
+                                           (vhash-cons key (vlist->list (cdr result)) results)
+                                           results)))
+                                   vlist-null
+                                   (cdr (vhash-assoc 'tracks db))))))
+    (if (null? r) #f r)))
+
+(define (read-cddb cddb-port)
+  (define (parse-cddb-line line db)
+    (define (line-match regex) (string-match regex line))
+
+    (cond
+     ((line-match "^#(.*)$") => (lambda (x) (vhash-cat 'comment (match:substring x 1) db)))
+     ((line-match "^DISCID=([[:graph:]]+)$") => (lambda (x) (let ((disc-db (cdr (vhash-assoc 'disc db))))
+                                                        (vhash-set 'disc (vhash-cat 'DISCID (match:substring x 1) disc-db)
+                                                                   db))))
+     ((line-match "^D([[:alpha:]]+)=([[:graph:][:space:]]+)$") => (lambda (x)
+                                                                   (let ((disc-db (cdr (vhash-assoc 'disc db)))
+                                                                         (key (string->symbol (match:substring x 1))))
+                                                                     (vhash-set 'disc (vhash-cat key (match:substring x 2) disc-db)
+                                                                                db))))
+   
+     ((line-match "^T([[:alpha:]]+)([[:digit:]]+)=([[:graph:][:space:]]+)$")
+      => (lambda (x)
+          (let* ((tracks-db (cdr (vhash-assoc 'tracks db)))
+                 (tracknum (string->number (match:substring x 2)))
+                 (tracknum-db ((lambda (vh) (if vh (cdr vh) vlist-null)) (vhash-assoc tracknum tracks-db)))
+                 (key (string->symbol (match:substring x 1)))
+                 (tag-value (match:substring x 3)))
+            (vhash-set 'tracks (vhash-set tracknum (vhash-cat key tag-value tracknum-db)
+                                          tracks-db)
+                       db))))
+   
+     ;; Also match EXTD? Might just punt if abcde handles it separately
+     (else db)))
+  
+  (stream-fold parse-cddb-line
+              (make-initial-db 'comment 'disc 'tracks)
+              (port->stream cddb-port read-line)))
+
+
+
+
+
+