Add new hand-crafted Python bindings

New bindings are Pythonic, supporting iteration, DWIM type conversion,
pretty printing, and so on, where possible.  Updated test suite covers
100% of binding code.  Which is to say: add real Python bindings.

As far as the Lilv API itself is concerned, you can do everything via
Python.  However, more work is needed to make fancy wrappers for parts
of LV2 itself (MIDI, URI map, etc) to be able to run advanced plugins.

1 files changed, 17 insertions, 22 deletions

diff --git a/bindings/python/lv2_apply.py b/bindings/python/lv2_apply.py
index 1cd906d..4c7d9b4 100755
--- a/bindings/python/lv2_apply.py
+++ b/bindings/python/lv2_apply.py
@@ -41,8 +41,8 @@ class WavFile(object):
             data = [(i - float(range/2)) / float(range/2) for i in data]
 
         channels = []
-        for i in xrange(self.nchannels):
-            channels.append([data[j] for j in xrange(0, len(data), self.nchannels) ])
+        for i in range(self.nchannels):
+            channels.append([data[j] for j in range(0, len(data), self.nchannels) ])
 
         return channels
 
@@ -57,6 +57,7 @@ def main():
 
     # Initialise Lilv
     world = lilv.World()
+    ns    = world.ns
     world.load_all()
 
     plugin_uri   = sys.argv[1]
@@ -65,19 +66,14 @@ def main():
 
     # Find plugin
     plugin_uri_node = world.new_uri(plugin_uri)
-    plugin          = world.get_all_plugins().get_by_uri(plugin_uri_node)
-    if not plugin:
-        print("Unknown plugin `%s'\n" % plugin_uri)
+    plugins         = world.get_all_plugins()
+    if plugin_uri_node not in plugins:
+        print("Unknown plugin `%s'" % plugin_uri)
         sys.exit(1)
 
-    lv2_InputPort   = world.new_uri(lilv.LILV_URI_INPUT_PORT)
-    lv2_OutputPort  = world.new_uri(lilv.LILV_URI_OUTPUT_PORT)
-    lv2_AudioPort   = world.new_uri(lilv.LILV_URI_AUDIO_PORT)
-    lv2_ControlPort = world.new_uri(lilv.LILV_URI_CONTROL_PORT)
-    lv2_default     = world.new_uri("http://lv2plug.in/ns/lv2core#default")
-
-    n_audio_in  = plugin.get_num_ports_of_class(lv2_InputPort,  lv2_AudioPort)
-    n_audio_out = plugin.get_num_ports_of_class(lv2_OutputPort, lv2_AudioPort)
+    plugin      = plugins[plugin_uri_node]
+    n_audio_in  = plugin.get_num_ports_of_class(ns.lv2.InputPort,  ns.lv2.AudioPort)
+    n_audio_out = plugin.get_num_ports_of_class(ns.lv2.OutputPort, ns.lv2.AudioPort)
     if n_audio_out == 0:
         print("Plugin has no audio outputs\n")
         sys.exit(1)
@@ -120,22 +116,21 @@ def main():
     control_output_buffers = []
     for index in range(plugin.get_num_ports()):
         port = plugin.get_port_by_index(index)
-        if port.is_a(lv2_InputPort):
-            if port.is_a(lv2_AudioPort):
+        if port.is_a(ns.lv2.InputPort):
+            if port.is_a(ns.lv2.AudioPort):
                 audio_input_buffers.append(numpy.array(channels[len(audio_input_buffers)], numpy.float32))
                 instance.connect_port(index, audio_input_buffers[-1])
-            elif port.is_a(lv2_ControlPort):
-                #if port.has_property(lv2_default):  # Doesn't seem to work
-                default = lilv.lilv_node_as_float(lilv.lilv_nodes_get_first(port.get_value(lv2_default)))
+            elif port.is_a(ns.lv2.ControlPort):
+                default = float(port.get(ns.lv2.default))
                 control_input_buffers.append(numpy.array([default], numpy.float32))
                 instance.connect_port(index, control_input_buffers[-1])
             else:
                 raise ValueError("Unhandled port type")
-        elif port.is_a(lv2_OutputPort):
-            if port.is_a(lv2_AudioPort):
+        elif port.is_a(ns.lv2.OutputPort):
+            if port.is_a(ns.lv2.AudioPort):
                 audio_output_buffers.append(numpy.array([0] * wav_in.nframes, numpy.float32))
                 instance.connect_port(index, audio_output_buffers[-1])
-            elif port.is_a(lv2_ControlPort):
+            elif port.is_a(ns.lv2.ControlPort):
                 control_output_buffers.append(numpy.array([0], numpy.float32))
                 instance.connect_port(index, control_output_buffers[-1])
             else:
@@ -156,7 +151,7 @@ def main():
     # Write output file in chunks to stop memory usage getting out of hand:
     CHUNK_SIZE = 8192
     for chunk in numpy.array_split(data, CHUNK_SIZE):
-        wav_out.writeframes(wave.struct.pack("%u%s" % (len(chunk), wav_in.struct_fmt_code), *chunk))
+        wav_out.writeframes(wave.struct.pack("%u%s" % (len(chunk), wav_in.struct_fmt_code), *chunk.astype(int)))
     wav_out.close()