Chris Angelico <ros...@gmail.com>:
> On Sat, Mar 1, 2014 at 5:53 AM, Marko Rauhamaa <ma...@pacujo.net> wrote:
>> A dict dispatch table is just awful.
>
> Really? How is that? I've used them, often. Yes, there are times when
> I could express something more cleanly with a C-style switch
> statement, but other times the dispatch table is fundamentally
> cleaner. I shared an example a few posts ago in this thread; care to
> elaborate on how it's "just awful"?
Your example:
compare_key = {
# Same target(s).
ast.Assign: lambda node: ' '.join(dump(t) for t in node.targets),
# Same target and same operator.
ast.AugAssign: lambda node: dump(node.target) + dump(node.op) + "=",
# A return statement is always compatible with another.
ast.Return: lambda node: "(easy)",
# Calling these never compatible is wrong. Calling them
# always compatible will give lots of false positives.
ast.Expr: lambda node: "(maybe)",
# These ones are never compatible, so return some
# object that's never equal to anything.
ast.Import: lambda node: float("nan"),
ast.ImportFrom: lambda node: float("nan"),
ast.Pass: lambda node: float("nan"),
ast.Raise: lambda node: float("nan"),
ast.If: lambda node: float("nan"),
}
vs (my proposal):
with key from ast:
if Assign:
return ' '.join(dump(t) for t in node.targets)
elif AugAssign:
# Same target and same operator.
return dump(node.target) + dump(node.op) + "="
elif Return:
# A return statement is always compatible with another.
return "(easy)"
elif Expr:
# Calling these never compatible is wrong. Calling them
# always compatible will give lots of false positives.
return "(maybe)"
else:
# These ones are never compatible, so return some
# object that's never equal to anything.
return float("nan")
Which do *you* find more readable?
Marko
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