Reworked query/value system to expose data type.

git-svn-id: http://svn.drobilla.net/lad/slv2@475 a436a847-0d15-0410-975c-d299462d15a1

16 files changed, 251 insertions, 202 deletions

diff --git a/doc/reference.doxygen.in b/doc/reference.doxygen.in
index a899bd3..bfcd911 100644
--- a/doc/reference.doxygen.in
+++ b/doc/reference.doxygen.in
@@ -420,19 +420,18 @@ WARN_LOGFILE           =
 # with spaces.
 
 INPUT = @top_srcdir@/doc/mainpage.dox \
+		@top_srcdir@/slv2/lv2.h \
 		@top_srcdir@/slv2/types.h \
+		@top_srcdir@/slv2/util.h \
+		@top_srcdir@/slv2/value.h \
+		@top_srcdir@/slv2/values.h \
 		@top_srcdir@/slv2/world.h \
-        @top_srcdir@/slv2/plugins.h \
-		@top_srcdir@/slv2/strings.h \
+        @top_srcdir@/slv2/plugin.h \
         @top_srcdir@/slv2/pluginclass.h \
         @top_srcdir@/slv2/pluginclasses.h \
-        @top_srcdir@/slv2/plugin.h \
-        @top_srcdir@/slv2/port.h \
         @top_srcdir@/slv2/plugininstance.h \
-		@top_srcdir@/slv2/util.h \
-		@top_srcdir@/slv2/lv2.h #\
-        #@top_srcdir@/slv2/query.h #\
-		#@top_srcdir@/include
+        @top_srcdir@/slv2/plugins.h \
+        @top_srcdir@/slv2/port.h
 
 
 # If the value of the INPUT tag contains directories, you can use the 
diff --git a/slv2/Makefile.am b/slv2/Makefile.am
index 05fc432..8e57eb1 100644
--- a/slv2/Makefile.am
+++ b/slv2/Makefile.am
@@ -2,15 +2,15 @@ slv2includedir = $(includedir)/slv2
 
 slv2include_HEADERS = \
 	lv2.h \
-	types.h \
-	slv2.h \
-	world.h \
+	plugin.h \
 	pluginclass.h \
 	pluginclasses.h \
-	plugin.h \
-	port.h \
-	plugins.h \
 	plugininstance.h \
-	strings.h \
-	util.h
-
+	plugins.h \
+	port.h \
+	slv2.h \
+	types.h \
+	util.h \
+	value.h \
+	values.h \
+	world.h
diff --git a/slv2/plugin.h b/slv2/plugin.h
index 7ec073b..c6090a6 100644
--- a/slv2/plugin.h
+++ b/slv2/plugin.h
@@ -90,7 +90,7 @@ slv2_plugin_get_uri(SLV2Plugin plugin);
  *
  * Time = O(1)
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_data_uris(SLV2Plugin plugin);
 
 
@@ -133,13 +133,13 @@ slv2_plugin_get_class(SLV2Plugin plugin);
  * <code>&lt;plugin-uri&gt; predicate ?object</code>
  * 
  * May return NULL if the property was not found, or if object is not
- * sensibly represented as an SLV2Strings (e.g. blank nodes).
+ * sensibly represented as an SLV2Values (e.g. blank nodes).
  *
- * Return value must be freed by caller with slv2_strings_free.
+ * Return value must be freed by caller with slv2_values_free.
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_value(SLV2Plugin  p,
                       const char* predicate);
 
@@ -154,13 +154,13 @@ slv2_plugin_get_value(SLV2Plugin  p,
  * (if information about it is contained in the plugin's data files).
  *
  * May return NULL if the property was not found, or if object is not
- * sensibly represented as an SLV2Strings (e.g. blank nodes).
+ * sensibly represented as an SLV2Values (e.g. blank nodes).
  *
- * Return value must be freed by caller with slv2_strings_free.
+ * Return value must be freed by caller with slv2_values_free.
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_value_for_subject(SLV2Plugin  p,
                                   const char* subject,
                                   const char* predicate);
@@ -176,7 +176,7 @@ slv2_plugin_get_value_for_subject(SLV2Plugin  p,
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_properties(SLV2Plugin p);
 
 
@@ -189,7 +189,7 @@ slv2_plugin_get_properties(SLV2Plugin p);
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_hints(SLV2Plugin p);
 
 
@@ -234,7 +234,7 @@ slv2_plugin_get_latency_port(SLV2Plugin p);
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_supported_features(SLV2Plugin p);
 
 
@@ -245,7 +245,7 @@ slv2_plugin_get_supported_features(SLV2Plugin p);
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_required_features(SLV2Plugin p);
 
 
@@ -257,7 +257,7 @@ slv2_plugin_get_required_features(SLV2Plugin p);
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_get_optional_features(SLV2Plugin p);
 
 
@@ -270,7 +270,7 @@ slv2_plugin_get_optional_features(SLV2Plugin p);
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_plugin_simple_query(SLV2Plugin  plugin,
                          const char* sparql_str,
                          const char* variable);
diff --git a/slv2/port.h b/slv2/port.h
index 165c1f1..10a2f3f 100644
--- a/slv2/port.h
+++ b/slv2/port.h
@@ -37,7 +37,7 @@ extern "C" {
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_port_get_value(SLV2Plugin  plugin,
                     SLV2Port    port,
                     const char* property);
@@ -47,7 +47,7 @@ slv2_port_get_value(SLV2Plugin  plugin,
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_port_get_properties(SLV2Plugin plugin,
                          SLV2Port   port);
 
@@ -56,7 +56,7 @@ slv2_port_get_properties(SLV2Plugin plugin,
  *
  * Time = Query
  */
-SLV2Strings
+SLV2Values
 slv2_port_get_hints(SLV2Plugin plugin,
                     SLV2Port   port);
 
diff --git a/slv2/slv2.h b/slv2/slv2.h
index ee0bcfa..f3a4a0d 100644
--- a/slv2/slv2.h
+++ b/slv2/slv2.h
@@ -30,7 +30,7 @@ extern "C" {
 #include <slv2/port.h>
 #include <slv2/plugins.h>
 #include <slv2/plugininstance.h>
-#include <slv2/strings.h>
+#include <slv2/values.h>
 
 #ifdef __cplusplus
 }
diff --git a/slv2/types.h b/slv2/types.h
index 7e965be..d55b81d 100644
--- a/slv2/types.h
+++ b/slv2/types.h
@@ -64,6 +64,14 @@ typedef struct _PluginClass* SLV2PluginClass;
 typedef void* SLV2PluginClasses;
 
 
+/** A typed value */
+typedef struct _Value* SLV2Value;
+
+
+/** A collection of typed values. */
+typedef void* SLV2Values;
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/slv2/strings.h b/slv2/values.h
index 20667ef..a8381cd 100644
--- a/slv2/strings.h
+++ b/slv2/values.h
@@ -16,10 +16,11 @@
  * 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-#ifndef __SLV2_STRINGS_H__
-#define __SLV2_STRINGS_H__
+#ifndef __SLV2_VALUES_H__
+#define __SLV2_VALUES_H__
 
 #include <stdbool.h>
+#include <slv2/value.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -27,26 +28,23 @@ extern "C" {
 
 /** \defgroup strings Collections of strings
  *
- * SLV2Strings is an ordered collection of strings which is fast for random
+ * SLV2Values is an ordered collection of strings which is fast for random
  * access by index (i.e. a fancy array).
  *
  * @{
  */
 
 
-typedef void* SLV2Strings;
-
-
-/** Allocate a new, empty SLV2Strings
+/** Allocate a new, empty SLV2Values
  */
-SLV2Strings
-slv2_strings_new();
+SLV2Values
+slv2_values_new();
 
 
 /** Get the number of elements in a string list.
  */
 unsigned
-slv2_strings_size(SLV2Strings list);
+slv2_values_size(SLV2Values list);
 
 
 /** Get a string from a string list at the given index.
@@ -55,8 +53,8 @@ slv2_strings_size(SLV2Strings list);
  *
  * Time = O(1)
  */
-const char*
-slv2_strings_get_at(SLV2Strings list, unsigned index);
+SLV2Value
+slv2_values_get_at(SLV2Values list, unsigned index);
 
 
 /** Return whether \a list contains \a string.
@@ -64,13 +62,13 @@ slv2_strings_get_at(SLV2Strings list, unsigned index);
  * Time = O(n)
  */
 bool
-slv2_strings_contains(SLV2Strings list, const char* string);
+slv2_values_contains(SLV2Values list, SLV2Value value);
 
 
 /** Free a string list.
  */
 void
-slv2_strings_free(SLV2Strings);
+slv2_values_free(SLV2Values);
 
 
 /** @} */
@@ -79,5 +77,5 @@ slv2_strings_free(SLV2Strings);
 }
 #endif
 
-#endif /* __SLV2_STRINGS_H__ */
+#endif /* __SLV2_VALUES_H__ */
 
diff --git a/src/Makefile.am b/src/Makefile.am
index cdc8793..f7b9f76 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,14 +5,15 @@ lib_LTLIBRARIES = libslv2.la
 libslv2_la_LIBADD = @REDLAND_LIBS@
 
 libslv2_la_SOURCES = \
-	slv2_internal.h \
-	world.c \
+	plugin.c \
 	pluginclass.c \
 	pluginclasses.c \
-	plugin.c \
-	query.c \
-	port.c \
-	plugins.c \
 	plugininstance.c \
-	strings.c \
-	util.c
+	plugins.c \
+	port.c \
+	query.c \
+	slv2_internal.h \
+	util.c \
+	value.c \
+	values.c \
+	world.c
diff --git a/src/plugin.c b/src/plugin.c
index 7efe6b7..19418fe 100644
--- a/src/plugin.c
+++ b/src/plugin.c
@@ -25,7 +25,7 @@
 #include <slv2/plugin.h>
 #include <slv2/types.h>
 #include <slv2/util.h>
-#include <slv2/strings.h>
+#include <slv2/values.h>
 #include "slv2_internal.h"
 
 
@@ -38,7 +38,7 @@ slv2_plugin_new(SLV2World world, librdf_uri* uri, const char* binary_uri)
 	plugin->plugin_uri = librdf_new_uri_from_uri(uri);
 	plugin->binary_uri = strdup(binary_uri);
 	plugin->plugin_class = NULL;
-	plugin->data_uris = slv2_strings_new();
+	plugin->data_uris = slv2_values_new();
 	plugin->ports = raptor_new_sequence((void (*)(void*))&slv2_port_free, NULL);
 	plugin->storage = NULL;
 	plugin->rdf = NULL;
@@ -70,7 +70,7 @@ slv2_plugin_free(SLV2Plugin p)
 		p->storage = NULL;
 	}
 	
-	slv2_strings_free(p->data_uris);
+	slv2_values_free(p->data_uris);
 
 	free(p);
 }
@@ -94,9 +94,9 @@ slv2_plugin_duplicate(SLV2Plugin p)
 	//result->bundle_url = strdup(p->bundle_url);
 	result->binary_uri = strdup(p->binary_uri);
 	
-	result->data_uris = slv2_strings_new();
-	for (unsigned i=0; i < slv2_strings_size(p->data_uris); ++i)
-		raptor_sequence_push(result->data_uris, strdup(slv2_strings_get_at(p->data_uris, i)));
+	result->data_uris = slv2_values_new();
+	for (unsigned i=0; i < slv2_values_size(p->data_uris); ++i)
+		raptor_sequence_push(result->data_uris, strdup(slv2_values_get_at(p->data_uris, i)));
 	
 	result->ports = raptor_new_sequence((void (*)(void*))&slv2_port_free, NULL);
 	for (int i=0; i < raptor_sequence_size(p->ports); ++i)
@@ -139,9 +139,10 @@ slv2_plugin_load(SLV2Plugin p)
 	}
 
 	// Parse all the plugin's data files into RDF model
-	for (unsigned i=0; i < slv2_strings_size(p->data_uris); ++i) {
-		const char* data_uri_str = slv2_strings_get_at(p->data_uris, i);
-		librdf_uri* data_uri = librdf_new_uri(p->world->world, (const unsigned char*)data_uri_str);
+	for (unsigned i=0; i < slv2_values_size(p->data_uris); ++i) {
+		SLV2Value data_uri_val = slv2_values_get_at(p->data_uris, i);
+		librdf_uri* data_uri = librdf_new_uri(p->world->world,
+				(const unsigned char*)slv2_value_as_uri(data_uri_val));
 		librdf_parser_parse_into_model(p->world->parser, data_uri, NULL, p->rdf);
 		librdf_free_uri(data_uri);
 	}
@@ -235,7 +236,7 @@ slv2_plugin_get_uri(SLV2Plugin p)
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_data_uris(SLV2Plugin p)
 {
 	return p->data_uris;
@@ -322,20 +323,23 @@ char*
 slv2_plugin_get_name(SLV2Plugin plugin)
 {
 	char* result     = NULL;
-	SLV2Strings prop = slv2_plugin_get_value(plugin, "doap:name");
+	SLV2Values prop = slv2_plugin_get_value(plugin, "doap:name");
 	
-	// FIXME: guaranteed to be the untagged one?
-	if (prop && slv2_strings_size(prop) >= 1)
-		result = strdup(slv2_strings_get_at(prop, 0));
+	// FIXME: lang? guaranteed to be the untagged one?
+	if (prop && slv2_values_size(prop) > 0) {
+		SLV2Value val = slv2_values_get_at(prop, 0);
+		if (slv2_value_is_string(val))
+			result = strdup(slv2_value_as_string(val));
+	}
 
 	if (prop)
-		slv2_strings_free(prop);
+		slv2_values_free(prop);
 
 	return result;
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_value(SLV2Plugin  p,
                       const char* predicate)
 {
@@ -346,7 +350,7 @@ slv2_plugin_get_value(SLV2Plugin  p,
 		"<> ", predicate, " ?value .\n"
 		"}\n", NULL);
 
-	SLV2Strings result = slv2_plugin_simple_query(p, query, "value");
+	SLV2Values result = slv2_plugin_simple_query(p, query, "value");
 	
 	free(query);
 
@@ -354,7 +358,7 @@ slv2_plugin_get_value(SLV2Plugin  p,
 }
 
 	
-SLV2Strings
+SLV2Values
 slv2_plugin_get_value_for_subject(SLV2Plugin  p,
                                   const char* subject,
                                   const char* predicate)
@@ -366,7 +370,7 @@ slv2_plugin_get_value_for_subject(SLV2Plugin  p,
 		subject, " ", predicate, " ?value .\n"
 		"}\n", NULL);
 
-	SLV2Strings result = slv2_plugin_simple_query(p, query, "value");
+	SLV2Values result = slv2_plugin_simple_query(p, query, "value");
 	
 	free(query);
 
@@ -374,14 +378,14 @@ slv2_plugin_get_value_for_subject(SLV2Plugin  p,
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_properties(SLV2Plugin p)
 {
 	return slv2_plugin_get_value(p, "lv2:pluginProperty");
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_hints(SLV2Plugin p)
 {
 	return slv2_plugin_get_value(p, "lv2:pluginHint");
@@ -399,18 +403,21 @@ bool
 slv2_plugin_has_latency(SLV2Plugin p)
 {
     const char* const query = 
-		"SELECT DISTINCT ?port WHERE {\n"
+		"ASK WHERE {\n"
 		"	<> lv2:port     ?port .\n"
-		"	?port   lv2:portHint lv2:reportsLatency .\n"
+		"	?port   lv2:portHint lv2:reportsLatency ;\n"
+		"           lv2:index    ?index .\n"
 		"}\n";
 
-	SLV2Strings results = slv2_plugin_simple_query(p, query, "port");
-	
-	bool exists = (slv2_strings_size(results) > 0);
+	SLV2Values results = slv2_plugin_simple_query(p, query, "port");
 	
-	slv2_strings_free(results);
-
-	return exists;
+	if (results) {
+		bool exists = (results && slv2_values_size(results) > 0);
+		slv2_values_free(results);
+		return exists;
+	} else {
+		return false;
+	}
 }
 
 
@@ -418,25 +425,24 @@ uint32_t
 slv2_plugin_get_latency_port(SLV2Plugin p)
 {
     const char* const query = 
-		"SELECT DISTINCT ?value WHERE {\n"
+		"SELECT DISTINCT ?index WHERE {\n"
 		"	<> lv2:port     ?port .\n"
 		"	?port   lv2:portHint lv2:reportsLatency ;\n"
 		"           lv2:index    ?index .\n"
 		"}\n";
 
-	SLV2Strings result = slv2_plugin_simple_query(p, query, "index");
+	SLV2Values result = slv2_plugin_simple_query(p, query, "index");
 	
 	// FIXME: need a sane error handling strategy
-	assert(slv2_strings_size(result) == 1);
-	char* endptr = 0;
-	uint32_t index = strtol(slv2_strings_get_at(result, 0), &endptr, 10);
-	// FIXME: check.. stuff..
+	assert(slv2_values_size(result) > 0);
+	SLV2Value val = slv2_values_get_at(result, 0);
+	assert(slv2_value_is_int(val));
 
-	return index;
+	return slv2_value_as_int(val);
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_supported_features(SLV2Plugin p)
 {
     const char* const query = 
@@ -446,13 +452,13 @@ slv2_plugin_get_supported_features(SLV2Plugin p)
 		"	{ <>  lv2:requiredHostFeature  ?feature }\n"
 		"}\n";
 
-	SLV2Strings result = slv2_plugin_simple_query(p, query, "feature");
+	SLV2Values result = slv2_plugin_simple_query(p, query, "feature");
 	
 	return result;
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_optional_features(SLV2Plugin p)
 {
     const char* const query = 
@@ -460,13 +466,13 @@ slv2_plugin_get_optional_features(SLV2Plugin p)
 		"	<>  lv2:optionalHostFeature  ?feature .\n"
 		"}\n";
 
-	SLV2Strings result = slv2_plugin_simple_query(p, query, "feature");
+	SLV2Values result = slv2_plugin_simple_query(p, query, "feature");
 	
 	return result;
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_plugin_get_required_features(SLV2Plugin p)
 {
     const char* const query = 
@@ -474,7 +480,7 @@ slv2_plugin_get_required_features(SLV2Plugin p)
 		"	<>  lv2:requiredHostFeature  ?feature .\n"
 		"}\n";
 
-	SLV2Strings result = slv2_plugin_simple_query(p, query, "feature");
+	SLV2Values result = slv2_plugin_simple_query(p, query, "feature");
 	
 	return result;
 }
diff --git a/src/plugins.c b/src/plugins.c
index ae450af..64f8430 100644
--- a/src/plugins.c
+++ b/src/plugins.c
@@ -26,7 +26,7 @@
 #include <slv2/types.h>
 #include <slv2/plugin.h>
 #include <slv2/plugins.h>
-#include <slv2/strings.h>
+#include <slv2/values.h>
 #include <slv2/util.h>
 #include "slv2_internal.h"
 
@@ -182,7 +182,7 @@ slv2_plugins_load_bundle(SLV2Plugins list,
 
 		SLV2Plugin plugin = slv2_plugins_get_by_uri(list, subject);
 
-		if (plugin && data_uri && !slv2_strings_contains(plugin->data_uris, data_uri))
+		if (plugin && data_uri && !slv2_values_contains(plugin->data_uris, data_uri))
 			raptor_sequence_push(plugin->data_uris, strdup(data_uri));
 		
 		if (plugin && binary && !plugin->lib_uri)
diff --git a/src/port.c b/src/port.c
index 5d18c8a..6744274 100644
--- a/src/port.c
+++ b/src/port.c
@@ -25,6 +25,7 @@
 #include <slv2/port.h>
 #include <slv2/types.h>
 #include <slv2/util.h>
+#include <slv2/values.h>
 #include "slv2_internal.h"
 
 
@@ -66,7 +67,7 @@ SLV2PortClass
 slv2_port_get_class(SLV2Plugin p,
                     SLV2Port   port)
 {
-	SLV2Strings class = slv2_port_get_value(p, port, "rdf:type");
+	SLV2Values class = slv2_port_get_value(p, port, "rdf:type");
 	assert(class);
 
 	SLV2PortClass ret = SLV2_UNKNOWN_PORT_CLASS;
@@ -74,18 +75,21 @@ slv2_port_get_class(SLV2Plugin p,
 	int io = -1; // 0 = in, 1 = out
 	enum { UNKNOWN, AUDIO, CONTROL, MIDI } type = UNKNOWN;
 
-	for (unsigned i=0; i < slv2_strings_size(class); ++i) {
-		const char* value = slv2_strings_get_at(class, i);
-		if (!strcmp(value, "http://lv2plug.in/ontology#InputPort"))
-			io = 0;
-		else if (!strcmp(value, "http://lv2plug.in/ontology#OutputPort"))
-			io = 1;
-		else if (!strcmp(value, "http://lv2plug.in/ontology#ControlPort"))
-			type = CONTROL;
-		else if (!strcmp(value, "http://lv2plug.in/ontology#AudioPort"))
-			type = AUDIO;
-		else if (!strcmp(value, "http://ll-plugins.nongnu.org/lv2/ext/MidiPort"))
-			type = MIDI;
+	for (unsigned i=0; i < slv2_values_size(class); ++i) {
+		SLV2Value val = slv2_values_get_at(class, i);
+		if (slv2_value_is_uri(val)) {
+			const char* uri = slv2_value_as_uri(val);
+			if (!strcmp(uri, "http://lv2plug.in/ontology#InputPort"))
+				io = 0;
+			else if (!strcmp(uri, "http://lv2plug.in/ontology#OutputPort"))
+				io = 1;
+			else if (!strcmp(uri, "http://lv2plug.in/ontology#ControlPort"))
+				type = CONTROL;
+			else if (!strcmp(uri, "http://lv2plug.in/ontology#AudioPort"))
+				type = AUDIO;
+			else if (!strcmp(uri, "http://ll-plugins.nongnu.org/lv2/ext/MidiPort"))
+				type = MIDI;
+		}
 	}
 
 	if (io == 0) {
@@ -104,20 +108,20 @@ slv2_port_get_class(SLV2Plugin p,
 			ret = SLV2_MIDI_OUTPUT;
 	}
 
-	slv2_strings_free(class);
+	slv2_values_free(class);
 
 	return ret;
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_port_get_value(SLV2Plugin  p,
                     SLV2Port    port,
                     const char* property)
 {
 	assert(property);
 
-	SLV2Strings result = NULL;
+	SLV2Values result = NULL;
 
 	char* query = slv2_strjoin(
 			"SELECT DISTINCT ?value WHERE {\n"
@@ -138,12 +142,12 @@ slv2_port_get_symbol(SLV2Plugin p,
 {
 	char* symbol = NULL;
 	
-	SLV2Strings result = slv2_port_get_value(p, port, "lv2:symbol");
+	SLV2Values result = slv2_port_get_value(p, port, "lv2:symbol");
 
-	if (result && slv2_strings_size(result) == 1)
-		symbol = strdup(slv2_strings_get_at(result, 0));
+	if (result && slv2_values_size(result) == 1)
+		symbol = strdup(slv2_value_as_string(slv2_values_get_at(result, 0)));
 	
-	slv2_strings_free(result);
+	slv2_values_free(result);
 
 	return symbol;
 }
@@ -155,12 +159,12 @@ slv2_port_get_name(SLV2Plugin p,
 {
 	char* name = NULL;
 	
-	SLV2Strings result = slv2_port_get_value(p, port, "lv2:name");
+	SLV2Values result = slv2_port_get_value(p, port, "lv2:name");
 
-	if (result && slv2_strings_size(result) == 1)
-		name = strdup(slv2_strings_get_at(result, 0));
+	if (result && slv2_values_size(result) == 1)
+		name = strdup(slv2_value_as_string(slv2_values_get_at(result, 0)));
 	
-	slv2_strings_free(result);
+	slv2_values_free(result);
 
 	return name;
 }
@@ -170,16 +174,14 @@ float
 slv2_port_get_default_value(SLV2Plugin p, 
                             SLV2Port   port)
 {
-	// FIXME: do casting properly in the SPARQL query
-	
 	float value = 0.0f;
 	
-	SLV2Strings result = slv2_port_get_value(p, port, "lv2:default");
+	SLV2Values result = slv2_port_get_value(p, port, "lv2:default");
 
-	if (result && slv2_strings_size(result) == 1)
-		value = atof(slv2_strings_get_at(result, 0));
+	if (result && slv2_values_size(result) == 1)
+		value = slv2_value_as_float(slv2_values_get_at(result, 0));
 	
-	slv2_strings_free(result);
+	slv2_values_free(result);
 
 	return value;
 }
@@ -189,16 +191,14 @@ float
 slv2_port_get_minimum_value(SLV2Plugin p, 
                             SLV2Port   port)
 {
-	// FIXME: need better access to literal types
-	
 	float value = 0.0f;
 	
-	SLV2Strings result = slv2_port_get_value(p, port, "lv2:minimum");
+	SLV2Values result = slv2_port_get_value(p, port, "lv2:minimum");
 
-	if (result && slv2_strings_size(result) == 1)
-		value = atof(slv2_strings_get_at(result, 0));
+	if (result && slv2_values_size(result) == 1)
+		value = slv2_value_as_float(slv2_values_get_at(result, 0));
 	
-	slv2_strings_free(result);
+	slv2_values_free(result);
 
 	return value;
 }
@@ -208,22 +208,20 @@ float
 slv2_port_get_maximum_value(SLV2Plugin p, 
                             SLV2Port   port)
 {
-	// FIXME: need better access to literal types
-	
 	float value = 0.0f;
 	
-	SLV2Strings result = slv2_port_get_value(p, port, "lv2:maximum");
+	SLV2Values result = slv2_port_get_value(p, port, "lv2:maximum");
 
-	if (result && slv2_strings_size(result) == 1)
-		value = atof(slv2_strings_get_at(result, 0));
+	if (result && slv2_values_size(result) == 1)
+		value = slv2_value_as_float(slv2_values_get_at(result, 0));
 	
-	slv2_strings_free(result);
+	slv2_values_free(result);
 
 	return value;
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_port_get_properties(SLV2Plugin p,
                          SLV2Port   port)
 {
@@ -231,7 +229,7 @@ slv2_port_get_properties(SLV2Plugin p,
 }
 
 
-SLV2Strings
+SLV2Values
 slv2_port_get_hints(SLV2Plugin p,
                     SLV2Port   port)
 {
diff --git a/src/query.c b/src/query.c
index 19eba56..bc1a7dc 100644
--- a/src/query.c
+++ b/src/query.c
@@ -23,7 +23,7 @@
 #include <librdf.h>
 #include <slv2/plugin.h>
 #include <slv2/util.h>
-#include <slv2/strings.h>
+#include <slv2/values.h>
 #include "slv2_internal.h"
 
 
@@ -51,31 +51,46 @@ slv2_query_lang_filter(const char* variable)
 }
 #endif
 
-SLV2Strings
+SLV2Values
 slv2_query_get_variable_bindings(librdf_query_results* results,
                                  const char*           variable)
 {
-	SLV2Strings result = NULL;
+	SLV2Values result = NULL;
 
     if (librdf_query_results_get_bindings_count(results) > 0)
-		result = slv2_strings_new();
+		result = slv2_values_new();
 
     while (!librdf_query_results_finished(results)) {
 
         librdf_node* node =
             librdf_query_results_get_binding_value_by_name(results, variable);
 		
-		char* str = NULL;
+		librdf_uri* datatype_uri = NULL;
+		SLV2ValueType type = SLV2_VALUE_STRING;
+		
+		const char* str_val = NULL;
 
 		switch (librdf_node_get_type(node)) {
 		case LIBRDF_NODE_TYPE_RESOURCE:
-			str = strdup((const char*)librdf_uri_as_string(librdf_node_get_uri(node)));
+			type = SLV2_VALUE_URI;
+			str_val = (const char*)librdf_uri_as_string(librdf_node_get_uri(node));
 			break;
 		case LIBRDF_NODE_TYPE_LITERAL:
-			str = strdup((const char*)librdf_node_get_literal_value(node));
+			datatype_uri = librdf_node_get_literal_value_datatype_uri(node);
+			if (datatype_uri) {
+				if (!strcmp((const char*)librdf_uri_as_string(datatype_uri),
+							"http://www.w3.org/2001/XMLSchema#integer"))
+					type = SLV2_VALUE_INT;
+				else if (!strcmp((const char*)librdf_uri_as_string(datatype_uri),
+							"http://www.w3.org/2001/XMLSchema#decimal"))
+					type = SLV2_VALUE_FLOAT;
+				else
+					fprintf(stderr, "Unknown datatype %s\n", librdf_uri_as_string(datatype_uri));
+			}
+			str_val = (const char*)librdf_node_get_literal_value(node);
 			break;
 		case LIBRDF_NODE_TYPE_BLANK:
-			str = strdup((const char*)librdf_node_get_blank_identifier(node));
+			str_val = (const char*)librdf_node_get_blank_identifier(node);
 			break;
 		case LIBRDF_NODE_TYPE_UNKNOWN:
 		default:
@@ -83,10 +98,8 @@ slv2_query_get_variable_bindings(librdf_query_results* results,
 			break;
 		}
 			
-		if (str) {
-			//printf("?%s = %s\n", variable, str);
-			raptor_sequence_push(result, str);
-		}
+		if (str_val)
+			raptor_sequence_push(result, slv2_value_new(type, str_val));
 
 		librdf_free_node(node);
 
@@ -124,33 +137,33 @@ slv2_plugin_query(SLV2Plugin  plugin,
 
 	//printf("******** Query \n%s********\n", query_str);
 	
-	librdf_query *rq = librdf_new_query(plugin->world->world, "sparql", NULL,
+	librdf_query* query = librdf_new_query(plugin->world->world, "sparql", NULL,
 			(const unsigned char*)query_str, base_uri);
 	
-	if (!rq) {
+	if (!query) {
 		fprintf(stderr, "ERROR: Could not create query\n");
 		return NULL;
 	}
 	
-	librdf_query_results* results = librdf_query_execute(rq, plugin->rdf);
+	librdf_query_results* results = librdf_query_execute(query, plugin->rdf);
 	
-	librdf_free_query(rq);
-
+	librdf_free_query(query);
 	free(query_str);
 
-	// FIXME: results leaked internally in places?
 	return results;
 }
 
 
 /** Query a single variable */
-SLV2Strings
+SLV2Values
 slv2_plugin_simple_query(SLV2Plugin  plugin,
                          const char* sparql_str,
                          const char* variable)
 {
 	librdf_query_results* results = slv2_plugin_query(plugin, sparql_str);
-	SLV2Strings ret = slv2_query_get_variable_bindings(results, variable);
+
+	SLV2Values ret = slv2_query_get_variable_bindings(results, variable);
+	
 	librdf_free_query_results(results);
 
 	return ret;
@@ -168,13 +181,14 @@ slv2_plugin_query_count(SLV2Plugin  plugin,
 {
 	librdf_query_results* results = slv2_plugin_query(plugin, sparql_str);
 
+	unsigned ret = 0;
+
 	if (results) {
-		unsigned ret = slv2_query_count_bindings(results);
+		ret = slv2_query_count_bindings(results);
 		librdf_free_query_results(results);
-		return ret;
-	} else {
-		return 0;
 	}
+
+	return ret;
 }
 
 /*
diff --git a/src/slv2_internal.h b/src/slv2_internal.h
index a9683c3..180f07d 100644
--- a/src/slv2_internal.h
+++ b/src/slv2_internal.h
@@ -30,6 +30,7 @@ extern "C" {
 #include <slv2/pluginclasses.h>
 
 
+
 /** Reference to a port on some plugin.
  */
 struct _Port {
@@ -119,6 +120,26 @@ slv2_world_load_path(SLV2World   world,
                      const char* search_path);
 
 
+typedef enum _ValueType {
+	SLV2_VALUE_URI,
+	SLV2_VALUE_STRING,
+	SLV2_VALUE_INT,
+	SLV2_VALUE_FLOAT
+} SLV2ValueType;
+
+struct _Value {
+	SLV2ValueType type;
+	char*         str_val; ///< always present
+	union {
+		int       int_val;
+		float     float_val;
+	} val;
+};
+
+SLV2Value slv2_value_new(SLV2ValueType type, const char* val);
+void      slv2_value_free(SLV2Value val);
+
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/strings.c b/src/values.c
index 39da54f..4920454 100644
--- a/src/strings.c
+++ b/src/values.c
@@ -20,46 +20,48 @@
 #include <stdlib.h>
 #include <limits.h>
 #include <raptor.h>
-#include <slv2/strings.h>
+#include <slv2/values.h>
+#include "slv2_internal.h"
 
 
-SLV2Strings
-slv2_strings_new()
+SLV2Values
+slv2_values_new()
 {
-	return raptor_new_sequence(&free, NULL);
+	return raptor_new_sequence((void (*)(void*))&slv2_value_free, NULL);
 }
 
 
 void
-slv2_strings_free(SLV2Strings list)
+slv2_values_free(SLV2Values list)
 {
 	raptor_free_sequence(list);
 }
 
 
 unsigned
-slv2_strings_size(SLV2Strings list)
+slv2_values_size(SLV2Values list)
 {
 	return raptor_sequence_size(list);
 }
 
 
-const char*
-slv2_strings_get_at(SLV2Strings list, unsigned index)
+SLV2Value
+slv2_values_get_at(SLV2Values list, unsigned index)
 {
 	if (index > INT_MAX)
 		return NULL;
 	else
-		return (const char*)raptor_sequence_get_at(list, (int)index);
+		return (SLV2Value)raptor_sequence_get_at(list, (int)index);
 }
 
 
 bool
-slv2_strings_contains(SLV2Strings list, const char* str)
+slv2_values_contains(SLV2Values list, SLV2Value value)
 {
-	for (unsigned i=0; i < slv2_strings_size(list); ++i)
-		if (!strcmp(slv2_strings_get_at(list, i), str))
+	for (unsigned i=0; i < slv2_values_size(list); ++i)
+		if (slv2_value_equals(slv2_values_get_at(list, i), value))
 			return true;
 	
 	return false;
 }
+
diff --git a/src/world.c b/src/world.c
index fa4cf1e..556ccf4 100644
--- a/src/world.c
+++ b/src/world.c
@@ -329,7 +329,7 @@ slv2_world_load_all(SLV2World world)
 
 		// FIXME: check for duplicates
 		raptor_sequence_push(plugin->data_uris,
-				strdup((const char*)librdf_uri_as_string(data_uri)));
+				slv2_value_new(SLV2_VALUE_URI, (const char*)librdf_uri_as_string(data_uri)));
 		
 		librdf_free_node(plugin_node);
 		librdf_free_node(data_node);
diff --git a/utils/lv2_inspect.c b/utils/lv2_inspect.c
index f1e1881..9245226 100644
--- a/utils/lv2_inspect.c
+++ b/utils/lv2_inspect.c
@@ -75,15 +75,15 @@ print_port(SLV2Plugin p, uint32_t index)
 
 	printf("\t\tProperties:\n");
 	SLV2Strings properties = slv2_port_get_properties(p, port);
-	for (unsigned i=0; i < slv2_strings_size(properties); ++i)
-		printf("\t\t\t%s\n", slv2_strings_get_at(properties, i));
-	slv2_strings_free(properties);
+	for (unsigned i=0; i < slv2_values_size(properties); ++i)
+		printf("\t\t\t%s\n", slv2_value_as_uri(slv2_values_get_at(properties, i)));
+	slv2_values_free(properties);
 	
 	printf("\t\tHints:\n");
 	SLV2Strings hints = slv2_port_get_hints(p, port);
-	for (unsigned i=0; i < slv2_strings_size(hints); ++i)
-		printf("\t\t\t%s\n", slv2_strings_get_at(hints, i));
-	slv2_strings_free(hints);
+	for (unsigned i=0; i < slv2_values_size(hints); ++i)
+		printf("\t\t\t%s\n", slv2_value_as_uri(slv2_values_get_at(hints, i)));
+	slv2_values_free(hints);
 }
 
 void
@@ -100,40 +100,42 @@ print_plugin(SLV2Plugin p)
 	const char* class_label = slv2_plugin_class_get_label(slv2_plugin_get_class(p));
 	printf("\tClass: %s\n\n", class_label);
 
-	if (slv2_plugin_has_latency(p))
-		printf("\tHas latency: yes\n\n");
-	else
+	if (slv2_plugin_has_latency(p)) {
+		uint32_t latency_port = slv2_plugin_get_latency_port(p);
+		printf("\tHas latency: yes, reported by port %d\n\n", latency_port);
+	} else {
 		printf("\tHas latency: no\n\n");
-	
+	}
+
 	printf("\tBinary: %s\n\n", slv2_plugin_get_library_uri(p));
 
 	printf("\tData URIs:\n");
 	SLV2Strings data_uris = slv2_plugin_get_data_uris(p);
-	for (unsigned i=0; i < slv2_strings_size(data_uris); ++i)
-		printf("\t\t%s\n", slv2_strings_get_at(data_uris, i));
+	for (unsigned i=0; i < slv2_values_size(data_uris); ++i)
+		printf("\t\t%s\n", slv2_value_as_uri(slv2_values_get_at(data_uris, i)));
 
 	/* Properties */
 
 	SLV2Strings v = slv2_plugin_get_properties(p);
 	
-	if (slv2_strings_size(v) > 0)
+	if (slv2_values_size(v) > 0)
 		printf("\n\tProperties:\n");
 
-	for (unsigned i=0; i < slv2_strings_size(v); ++i)
-		printf("\t\t%s\n", slv2_strings_get_at(v, i));
-	slv2_strings_free(v);
+	for (unsigned i=0; i < slv2_values_size(v); ++i)
+		printf("\t\t%s\n", slv2_value_as_uri(slv2_values_get_at(v, i)));
+	slv2_values_free(v);
 	
 
 	/* Hints */
 
 	v = slv2_plugin_get_hints(p);
 
-	if (slv2_strings_size(v) > 0)
+	if (slv2_values_size(v) > 0)
 		printf("\n\tHints:\n");
 
-	for (unsigned i=0; i < slv2_strings_size(v); ++i)
-		printf("\t\t%s\n", slv2_strings_get_at(v, i));
-	slv2_strings_free(v);
+	for (unsigned i=0; i < slv2_values_size(v); ++i)
+		printf("\t\t%s\n", slv2_value_as_uri(slv2_values_get_at(v, i)));
+	slv2_values_free(v);
 
 
 	/* Ports */