[Python-Dev] dict() enhancement idea? (original) (raw)

Just van Rossum just@letterror.com
Thu, 21 Nov 2002 16:16:29 +0100

Oren Tirosh wrote:

I assume that the motive is to get rid of the quotes around the key and conceptually treat it as a "symbol" rather than as a string. If that is the case it could apply to access as well as initialization.

class record(dict): _def init(self, initfrom=(), **kw): self.dict = self _dict.init(self, initfrom) self.update(kw) def repr(self): return "%s(%s)" % (self.class.name, ', '.join(['%s=%s' % (k, repr(v)) for k,v in self.items()])) Fields can be accessed as either items or attributes of a record object.

(Neat! Would've never guessed that works... I actually wrote a class with this purpose the other day, I'll see whether I can use the above instead.)

But: no, I simply find the {"key": "value"} syntax sometimes inappropriate. Consider the following example:

template = """some elaborate template using %(name)s-style substitution"""

idiom 1

x = template % {"name1": foo(), "name2": baz()}

idiom 2

name1 = foo() name2 = foo() x = template % locals()

idiom 3 (after my patch, or with a homegrown function)

x = template % dict(key1=foo(), key2=baz())

I find #3 more readable than #1. #2 ain't so bad, but I hate it that when you're quickly going over the code it looks like there are some unused variables.

Just