Merge pull request #509 from chme/smartplstartswith

[smartpl] Add "starts with" to smart playlist language

README_SMARTPL.md

@@ -44,13 +44,14 @@ Where valid field-names (with their types) are:
 * time_played (date)
 
 Valid operators include:
-* is, includes (string)
+* is, includes, starts with (string)
 * >, <, <=, >=, = (int)
 * after, before (date)
 * is (enumeration)
 
 The "is" operator must exactly match the field value, while the "includes" operator matches a substring.
-Both matches are case-insensitive.
+The "starts with" operator matches, if the value starts with the given prefix.
+All three matches are case-insensitive.
 
 Valid operands include:
 * "string value" (string)

src/SMARTPL.g

@@ -38,7 +38,7 @@ nexpr		:	NOT^ crit
 			;
 
 crit		:	LPAR expression RPAR	->	expression
-			|	STRTAG (INCLUDES|IS) STR
+			|	STRTAG (INCLUDES|IS|STARTSWITH) STR
 			|	INTTAG INTBOOL INT
 			|	DATETAG	(AFTER|BEFORE) dateval
 			|	ENUMTAG IS ENUMVAL
@@ -85,6 +85,9 @@ INCLUDES	:	'includes'
 IS			:	'is'
 			;
 
+STARTSWITH	:	'starts with'
+			;
+
 INTBOOL		:	(GREATER|GREATEREQUAL|LESS|LESSEQUAL|EQUAL)
 			;
 

src/SMARTPL2SQL.g

@@ -114,6 +114,20 @@ expression	returns [ pANTLR3_STRING result ]
 			$result->append8($result, sqlite3_mprintf("\%q", (const char *)val));
 			$result->append8($result, "'");
 		}
+	|	STRTAG STARTSWITH STR
+		{
+			pANTLR3_UINT8 val;
+			val = $STR.text->toUTF8($STR.text)->chars;
+			val++;
+			val[strlen((const char *)val) - 1] = '\0';
+			
+			$result = $STR.text->factory->newRaw($STR.text->factory);
+			$result->append8($result, "f.");
+			$result->appendS($result, $STRTAG.text->toUTF8($STRTAG.text));
+			$result->append8($result, " LIKE '");
+			$result->append8($result, sqlite3_mprintf("\%q", (const char *)val));
+			$result->append8($result, "\%'");
+		}
 	|	INTTAG INTBOOL INT
 		{
 			$result = $INTTAG.text->factory->newRaw($INTTAG.text->factory);