Add COMMENT keyword to smart playlists

contrib/mt-daapd.playlist

@@ -21,6 +21,7 @@
 #   Conductor (string)
 #   Grouping (string) -- I don't even know what this is...
 #   Comment (string)
+#   Type (string) -- "mp3 audio file", "m4a audio file", etc.
 #   Year (int)
 #   BPM (int)
 #   Bitrate (int)

src/lexer.l

@@ -55,6 +55,7 @@ orchestra                { yylval.ival=ORCHESTRA; return(ORCHESTRA); }
 conductor                { yylval.ival=CONDUCTOR; return(CONDUCTOR); }
 grouping                 { yylval.ival=GROUPING; return(GROUPING); }
 type                     { yylval.ival=TYPE; return(TYPE); }
+comment                  { yylval.ival=COMMENT; return(COMMENT); }
 
 year                     { yylval.ival=YEAR; return(YEAR); }
 bpm                      { yylval.ival=BPM; return(BPM); }

src/parser.y

@@ -63,6 +63,7 @@ int pl_number=2;
 %token <ival> CONDUCTOR
 %token <ival> GROUPING
 %token <ival> TYPE
+%token <ival> COMMENT
 
 %token <ival> EQUALS
 %token <ival> LESS
@@ -162,6 +163,7 @@ strtag: ARTIST
 | CONDUCTOR
 | GROUPING
 | TYPE
+| COMMENT
 ;
 
 strbool: IS { $$=$1; }

src/playlist.c

@@ -119,6 +119,9 @@ void pl_dump_node(PL_NODE *pnode, int indent) {
     case TYPE:
 	printf("TYPE ");
 	break;
+    case COMMENT:
+	printf("COMMENT ");
+	break;
     case YEAR:
 	printf("YEAR ");
 	break;
@@ -313,6 +316,9 @@ int pl_eval_node(MP3FILE *pmp3, PL_NODE *pnode) {
     case TYPE:
 	cval=pmp3->description;
 	break;
+    case COMMENT:
+	cval=pmp3->comment;
+	break;
     case YEAR:
 	ival=pmp3->year;
 	break;