## START CODE ###########################################
def foo():
# foo represents a patternless function
# or method that returns a Boolean value
# based on some internal test.
#
if 1==1:
return True
return False
#
# The fun begins when two tiny chars are forgotten,
# however, since the code is legal, python will happily
# give us the wrong answer.
#
if foo: # <- forgot parenthesis!
print 'implicit conversion to bool bites!'
else:
#
# This block will NEVER execute because foo is
# ALWAYS True!
#
#
# Some introspection to understand why this happened.
#
print 'foo =', foo
print 'bool(foo) ->', bool(foo)
#
## END CODE #############################################
It's obvious i did not follow the syntactical rules of
Python, i understand that, however, there are three design
flaws here that are contributing to this dilemma:
1. Implicit conversion to Boolean is evil
2. Conditionals should never accept parameter-less
functions. If you want to check if a callable is
True or False, then use "if bool(callable)". Any
usage of a bare callable in conditionals should
raise SyntaxError.
3. Implicit introspection is evil, i prefer all
references to a callable's names to result in a CALL
to that callable, not an introspection!
Introspection should ALWAYS be explicit!
For a long time i thought Python's idea of a returning the
value of a callable-- who's name is unadorned with "(...)"
--was a good idea, however, i am now wholly convinced that
this design is folly, and the reason is two fold:
1. Parenthesis should not be required for parameter-
less functions. I realize this is a bit more
complicated in languages like Python where
attributes are exposed to the public, but still, not
reason enough to require such onerous typing.
2. Implicit introspection is evil. I would prefer an
explicit method attached to all callables over a
sugar for "callable.call". We should never consume
syntactical sugars UNLESS they can greatly reduce
the density of code (like math operators for
instance!)
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