nes_gamepad: adjust Python style of decoder implementation

Rephrase the NES gamepad decoder to become more idiomatic Python.
Address nits to better match the sigrok project's coding style.
Eliminate hidden coupling by means of instance variables.

diff --git a/decoders/nes_gamepad/pd.py b/decoders/nes_gamepad/pd.py
index b276e5db7bf173ec31b7e7ccad929ba8a5ecf8c3..a393abfac6b103fcc9d411b8b5afeb1dbf3aefbc 100644 (file)
--- a/decoders/nes_gamepad/pd.py
+++ b/decoders/nes_gamepad/pd.py
@@ -51,24 +51,22 @@ class Decoder(srd.Decoder):
 
     def reset(self):
         self.variant = None
-        self.ss_block = None
-        self.es_block = None
 
     def start(self):
         self.out_ann = self.register(srd.OUTPUT_ANN)
         self.variant = self.options['variant']
 
-    def putx(self, data):
-        self.put(self.ss_block, self.es_block, self.out_ann, data)
+    def putg(self, ss, es, cls, text):
+        self.put(ss, es, self.out_ann, [cls, [text]])
 
-    def handle_data(self, value):
-        if value == 0xFF:
-          self.putx([1, ['No button is pressed']])
-          return
+    def handle_data(self, ss, es, value):
+        if value == 0xff:
+            self.putg(ss, es, 1, 'No button is pressed')
+            return
 
         if value == 0x00:
-          self.putx([2, ['Gamepad is not connected']])
-          return
+            self.putg(ss, es, 2, 'Gamepad is not connected')
+            return
 
         buttons = [
             'A',
@@ -78,28 +76,17 @@ class Decoder(srd.Decoder):
             'North',
             'South',
             'West',
-            'East'
+            'East',
         ]
 
-        bits = format(value, '08b')
-        button_str = ''
-
-        for b in enumerate(bits):
-            button_index = b[0]
-            button_is_pressed = b[1] == '0'
-
-            if button_is_pressed:
-                if button_str != '':
-                    button_str += ' + '
-                button_str += buttons[button_index]
-
-        self.putx([0, ['%s' % button_str]])
+        bits = '{:08b}'.format(value)
+        text = [buttons[i] for i, b in enumerate(bits) if b == '0']
+        text = ' + '.join(text)
+        self.putg(ss, es, 0, text)
 
     def decode(self, ss, es, data):
-        ptype, mosi, miso = data
-        self.ss_block, self.es_block = ss, es
-
-        if ptype != 'DATA':
-          return
-
-        self.handle_data(miso)
+        ptype, _, _ = data
+        if ptype == 'DATA':
+            _, _, miso = data
+            self.handle_data(ss, es, miso)
+            return