migen.fhdl.structure: add Signal.like(other)

jordens · sbourdeauducq · commit 44c6e524ba97 · 2014-07-24T23:52:59.000-06:00
This is a convenience method. Signal(flen(other)) is used frequently but that
drops the signedness. Signal((other.nbits, other.signed)) would be correct but
is long.
diff --git a/migen/fhdl/structure.py b/migen/fhdl/structure.py
@@ -274,6 +274,20 @@ def __init__(self, bits_sign=None, name=None, variable=False, reset=0, name_over
 	def __repr__(self):
 		return "<Signal " + (self.backtrace[-1][0] or "anonymous") + " at " + hex(id(self)) + ">"
 
+	@classmethod
+	def like(cls, other):
+		"""Create Signal based on another.
+
+		Parameters
+		----------
+		other : Value
+			Object to base this Signal on.
+
+		See `migen.fhdl.bitcontainer.value_bits_sign`() for details.
+		"""
+		from migen.fhdl.bitcontainer import value_bits_sign
+		return cls(value_bits_sign(other))
+
 class ClockSignal(Value):
 	"""Clock signal for a given clock domain
 
