adf435x: use .format() for Python string formatting

Rephrase the old style '%' operator string formatting, prefer .format()
calls instead. It is assumed that routine call argument lists are more
readable than optional/conditional tuples are, and not running format
specifiers and literal text into each other helps readability as well,
as do the .format() routine's optionally named references to parameters.

Avoid text formatting which involves concatenation, always work from one
single format instruction instead.

Author: gsigh

decoders/adf435x/pd.py

@@ -24,7 +24,7 @@ def disabled_enabled(v):
     return ['Disabled', 'Enabled'][v]
 
 def output_power(v):
-    return '%+ddBm' % [-4, -1, 2, 5][v]
+    return '{:+d}dBm'.format([-4, -1, 2, 5][v])
 
 regs = {
 # reg:   name                        offset width parser
@@ -45,9 +45,9 @@ def output_power(v):
         ('PD Polarity',                   6,  1, lambda v: ['Negative', 'Positive'][v]),
         ('LDP',                           7,  1, lambda v: ['10ns', '6ns'][v]),
         ('LDF',                           8,  1, lambda v: ['FRAC-N', 'INT-N'][v]),
-        ('Charge Pump Current Setting',   9,  4, lambda v: '%0.2fmA @ 5.1kΩ' %
+        ('Charge Pump Current Setting',   9,  4, lambda v: '{:0.2f}mA @ 5.1kΩ'.format(
             [0.31, 0.63, 0.94, 1.25, 1.56, 1.88, 2.19, 2.50,
-            2.81, 3.13, 3.44, 3.75, 4.06, 4.38, 4.69, 5.00][v]),
+            2.81, 3.13, 3.44, 3.75, 4.06, 4.38, 4.69, 5.00][v])),
         ('Double Buffer',                13,  1, disabled_enabled),
         ('R Counter',                    14, 10, None),
         ('RDIV2',                        24,  1, disabled_enabled),
@@ -75,9 +75,9 @@ def output_power(v):
         ('AUX Output Enable',             9,  1, disabled_enabled),
         ('MTLD',                         10,  1, disabled_enabled),
         ('VCO Power-Down',               11,  1, lambda v:
-            'VCO Powered ' + ('Down' if v == 1 else 'Up')),
+            'VCO Powered {updown}'.format(updown = 'Down' if v else 'Up')),
         ('Band Select Clock Divider',    12,  8, None),
-        ('RF Divider Select',            20,  3, lambda v: '÷' + str(2**v)),
+        ('RF Divider Select',            20,  3, lambda v: '÷{:d}'.format(2 ** v)),
         ('Feedback Select',              23,  1, lambda v: ['Divided', 'Fundamental'][v]),
     ],
     5: [
@@ -131,16 +131,17 @@ def decode_bits(self, offset, width):
     def decode_field(self, name, offset, width, parser):
         '''Interpret a bit field. Emits an annotation.'''
         val, ( ss, es, ) = self.decode_bits(offset, width)
-        val = parser(val) if parser else str(val)
-        text = ['%s: %s' % (name, val)]
+        val = parser(val) if parser else '{}'.format(val)
+        text = ['{name}: {val}'.format(name = name, val = val)]
         self.putg(ss, es, ANN_REG, text)
 
     def decode_word(self, ss, es, bits):
         '''Interpret a 32bit word after accumulation completes.'''
         # SPI transfer content must be exactly one 32bit word.
-        if len(self.bits) != 32:
+        count = len(self.bits)
+        if count != 32:
             text = [
-                'Frame error: Bit count: want 32, got %d' % len(self.bits),
+                'Frame error: Bit count: want 32, got {}'.format(count),
                 'Frame error: Bit count',
                 'Frame error',
             ]
@@ -153,9 +154,9 @@ def decode_word(self, ss, es, bits):
         # Determine which register was accessed.
         reg_addr, ( reg_ss, reg_es, ) = self.decode_bits(0, 3)
         text = [
-            'Register: %d' % reg_addr,
-            'Reg: %d' % reg_addr,
-            '[%d]' % reg_addr,
+            'Register: {addr}'.format(addr = reg_addr),
+            'Reg: {addr}'.format(addr = reg_addr),
+            '[{addr}]'.format(addr = reg_addr),
         ]
         self.putg(reg_ss, reg_es, ANN_REG, text)
         # Interpret the register's content (when parsers are available).