Add bpm keyword to smart playlists

contrib/mt-daapd.playlist

@@ -21,6 +21,7 @@
 #   Conductor (string)
 #   Grouping (string) -- I don't even know what this is...
 #   Year (int)
+#   BPM (int)
 #
 # Valid operators include:
 #   is, includes (string)

src/lexer.l

@@ -52,6 +52,7 @@ conductor                { yylval.ival=CONDUCTOR; return(CONDUCTOR); }
 grouping                 { yylval.ival=GROUPING; return(GROUPING); }
 
 year                     { yylval.ival=YEAR; return(YEAR); }
+bpm                      { yylval.ival=BPM; return(BPM); }
 
 is                       { yylval.ival=IS; return(IS); }
 includes                 { yylval.ival=INCLUDES; return(INCLUDES); }

src/parser.y

@@ -78,6 +78,7 @@ int pl_number=2;
 %token <ival> NUM
 
 %token <ival> YEAR
+%token <ival> BPM
 
 %type <plval> expression
 %type <plval> predicate
@@ -107,6 +108,7 @@ predicate: strtag strbool ID { $$=pl_newcharpredicate($1, $2, $3); }
 ;
 
 inttag: YEAR
+| BPM
 ;
 
 intbool: EQUALS { $$ = $1; }

src/playlist.c

@@ -116,6 +116,9 @@ void pl_dump_node(PL_NODE *pnode, int indent) {
     case YEAR:
 	printf("YEAR ");
 	break;
+    case BPM:
+	printf("BPM ");
+	break;
     default:
 	printf ("<unknown tag> ");
 	break;
@@ -287,6 +290,9 @@ int pl_eval_node(MP3FILE *pmp3, PL_NODE *pnode) {
     case YEAR:
 	ival=pmp3->year;
 	break;
+    case BPM:
+	ival=pmp3->bpm;
+	break;
     }
 
     boolarg=(pnode->op) & 0x7FFFFFFF;