Manual – cue-parser

cue-parser is a parser for audio CUE sheets based on esrap.

You can parse a CUE sheet ether from a character stream using function parse-cue or a file using parse-cue-file. parse-cue-file uses an external format stored in *cue-external-format* by default for reading from files. Each function returns a parsed representation of the file in form of list. There are some helper functions to get data from that representation.

For example, if you parse following CUE file:

REM GENRE Gothic
REM DATE 2010
REM DISCID 4807E106
REM COMMENT "ExactAudioCopy v1.0b1"
PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
TITLE "A Strange Thing To Say"
FILE "Sopor Aeternus & The Ensemble Of Shadows - A Strange Thing To Say.flac" WAVE
  TRACK 01 AUDIO
    TITLE "A Strange Thing To Say"
    PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
    INDEX 01 00:00:00
  TRACK 02 AUDIO
    TITLE "Polishing Silver"
    PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
    INDEX 00 09:41:69
    INDEX 01 09:43:47
  TRACK 03 AUDIO
    TITLE "The Urine Song"
    PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
    INDEX 00 14:52:58
    INDEX 01 14:55:06
  TRACK 04 AUDIO
    TITLE "Stains Of You"
    PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
    INDEX 00 19:11:22
    INDEX 01 19:13:26
  TRACK 05 AUDIO
    TITLE "20.000 Leagues Under The Sea"
    PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
    INDEX 00 23:17:62
    INDEX 01 23:19:40
  TRACK 06 AUDIO
    TITLE "Oh, Chimney Sweep"
    PERFORMER "Sopor Aeternus & The Ensemble Of Shadows"
    INDEX 00 29:57:03
    INDEX 01 29:59:14

you will get the following parsed representation:

(((:REM . " GENRE Gothic")(:REM . " DATE 2010")(:REM . " DISCID 4807E106")
  (:REM . " COMMENT \"ExactAudioCopy v1.0b1\"")
  (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
  (:TITLE . "A Strange Thing To Say"))
 (((:FILE :NAME
    "Sopor Aeternus & The Ensemble Of Shadows - A Strange Thing To Say.flac"
    :TYPE "WAVE")
   (:TRACK :NUMBER 1 :TYPE "AUDIO")(:TITLE . "A Strange Thing To Say")
   (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
   (:INDEX :NUMBER 1 :MIN 0 :SEC 0))
  ((:TRACK :NUMBER 2 :TYPE "AUDIO")(:TITLE . "Polishing Silver")
   (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
   (:INDEX :NUMBER 0 :MIN 9 :SEC 41)(:INDEX :NUMBER 1 :MIN 9 :SEC 43))
  ((:TRACK :NUMBER 3 :TYPE "AUDIO")(:TITLE . "The Urine Song")
   (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
   (:INDEX :NUMBER 0 :MIN 14 :SEC 52)(:INDEX :NUMBER 1 :MIN 14 :SEC 55))
  ((:TRACK :NUMBER 4 :TYPE "AUDIO")(:TITLE . "Stains Of You")
   (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
   (:INDEX :NUMBER 0 :MIN 19 :SEC 11)(:INDEX :NUMBER 1 :MIN 19 :SEC 13))
  ((:TRACK :NUMBER 5 :TYPE "AUDIO")(:TITLE . "20.000 Leagues Under The Sea")
   (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
   (:INDEX :NUMBER 0 :MIN 23 :SEC 17)(:INDEX :NUMBER 1 :MIN 23 :SEC 19))
  ((:TRACK :NUMBER 6 :TYPE "AUDIO")(:TITLE . "Oh, Chimney Sweep")
   (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
   (:INDEX :NUMBER 0 :MIN 29 :SEC 57)(:INDEX :NUMBER 1 :MIN 29 :SEC 59))))

As you probably see, this representation is a list with 2 elements. The first element contains all CUE commands preceding the first TRACK command, and the second is a list of tracks. You can get both with first and second functions, or, which is the same, with get-toplevel and get-tracks.

If you want, for example, get the name of the album, you can use get-command-arg function with toplevel block:

(let ((tree (parse-cue-file "album.cue")))
       (get-command-arg (get-toplevel tree) :title))
   >>> "A Strange Thing To Say"

You can get a track by an index in the block of tracks, for example, (nth 1 (second tree)) returns the second track. You can also use a function called get-track-by-idx for the same purpose. In the following example the name of the second track is returned:

(let ((tree (parse-cue-file "album.cue")))
       (get-command-arg (get-track-by-idx tree 1) :title))
   >>> "Polishing Silver"

If a command argument is a property list, you can use get-command-named-arg to get what you want. Calling (get-command-named-arg tree command arg-name) equals to (getf (get-command-arg tree command) arg-name).

You can get a file name in which the track is stored by calling get-file-name:

(let ((tree (parse-cue-file "album.cue")))
       (get-file-name tree (get-track-by-idx tree 3)))
   >>> "Sopor Aeternus & The Ensemble Of Shadows - A Strange Thing To Say.flac"

This is the only way to get a file name. Calling get-command-arg in this case is incorrect.

If you want to get a time offset in seconds from the beggining of the file for a particular track, use get-track-index-sec.

Finally, if you want to search for a track by a specific criterion, use find-track function. This is simply a wrapper around find-if and requires a predicate to do the search. For example, you can find a track which name is "The Urine Song" (yep, sounds suspicious, I know ;):

(let ((tree (parse-cue-file "album.cue")))
       (find-track tree
                   (lambda (track)(string= "The Urine Song"
                                            (get-command-arg track :title)))))
   >>> ((:TRACK :NUMBER 3 :TYPE "AUDIO")(:TITLE . "The Urine Song")
        (:PERFORMER . "Sopor Aeternus & The Ensemble Of Shadows")
        (:INDEX :NUMBER 0 :MIN 14 :SEC 52)(:INDEX :NUMBER 1 :MIN 14 :SEC 55))

That's all. If you wish, you can totally ignore these functions and use find/car/cdr or whatever you wish to get data from parsed file as its representation is a simple list.

cue-parser » Manual