fix: more pointer type safety in example plugins

Signed-off-by: Christopher Arndt <chris@chrisarndt.de>

examples/amp_plugin.nim

@@ -33,7 +33,7 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
 
         if plug.map.isNil:
             freeShared(plug)
-            return nil
+            return cast[Lv2Handle](nil)
 
         let logPtr = cast[ptr Log](lv2FeaturesData(features, lv2LogLog))
 
@@ -43,7 +43,7 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
         plug.log.note("nymph amp LV2 plugin instance created.")
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;

examples/faustlpf_plugin.nim

@@ -21,12 +21,12 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
     try:
-        let plug = cast[ptr FaustLPFPlugin](createShared(FaustLPFPlugin))
+        let plug: ptr FaustLPFPlugin = createShared(FaustLPFPlugin)
         plug.flt = newfaustlpf()
         initfaustlpf(plug.flt, sampleRate.cint)
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -73,7 +73,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

examples/miditranspose_plugin.nim

@@ -28,16 +28,19 @@ type
 proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
+    try:
         let plug: ptr MidiTransposePlugin = createShared(MidiTransposePlugin)
         plug.map = cast[ptr UridMap](lv2FeaturesData(features, lv2UridMap))
 
         if plug.map.isNil:
             freeShared(plug)
-        return nil
+            return cast[Lv2Handle](nil)
 
         plug.midi_urid = plug.map.map(plug.map.handle, lv2MidiMidiEvent)
 
         return cast[Lv2Handle](plug)
+    except OutOfMemDefect:
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -95,7 +98,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

examples/multimodefilter_plugin.nim

@@ -27,12 +27,12 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
     try:
-        let plug = createShared(SVFPlugin)
+        let plug: ptr SVFPlugin = createShared(SVFPlugin)
         plug.svf = initSVFilter(fmLowPass, sampleRate)
         plug.smoothCutoff = initParamSmooth(20.0, sampleRate)
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -91,7 +91,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

examples/tiltfilter_plugin.nim

@@ -30,12 +30,12 @@ proc instantiate(descriptor: ptr Lv2Descriptor; sampleRate: cdouble;
                  bundlePath: cstring; features: ptr UncheckedArray[ptr Lv2Feature]):
                  Lv2Handle {.cdecl.} =
     try:
-        let plug = createShared(TiltFilterPlugin)
+        let plug: ptr TiltFilterPlugin = createShared(TiltFilterPlugin)
         plug.flt = initTiltFilter(10_000.0, 1.0, fmLowPass, sampleRate)
         plug.smoothFreq = initParamSmooth(20.0, sampleRate)
         return cast[Lv2Handle](plug)
     except OutOfMemDefect:
-        return nil
+        return cast[Lv2Handle](nil)
 
 
 proc connectPort(instance: Lv2Handle; port: cuint;
@@ -91,7 +91,7 @@ let descriptor = Lv2Descriptor(
 )
 
 proc lv2Descriptor(index: cuint): ptr Lv2Descriptor {.
-                   cdecl, exportc, dynlib, extern: "lv2_descriptor".} =
+                   cdecl, dynlib, exportc: "lv2_descriptor".} =
     if index == 0:
         NimMain()
         return addr(descriptor)

src/nymph/core.nim

@@ -92,7 +92,8 @@ const
     lv2CoreInstanceSampleRate* = lv2CorePrefix & "sampleRate"
     lv2CoreInstanceToggled* = lv2CorePrefix & "toggled"
 
-type Lv2Handle* = pointer
+type
+    Lv2Handle* = distinct pointer
 
 type Lv2Feature* = object
     uri*: cstring