I think this is a philosophical ruby question.
Why does ruby allow fixnums to be accessed as hashes?
5[:some_key]
=> 0
Not all types can be used this way:
3.1415[:some_key]
NoMethodError: undefined method '[]' for Float
Array.new()[:some_key]
TypeError: Symbol as array index
etc.
And the perhaps larger question -- why would 5[:some_key] return *zero*,
when all other hash-y accesses to nonexistent keys (that I know of)
return *nil*?
Can be dangerous situations like:
def f(options)
# Only execute following if caller has called us with :do_bad_stuff => true
if (options[:do_bad_stuff]) # <--- idiomatically common
# watch out... Bad stuff here!
end
end
If options somehow were a Fixnum above (don't ask! :-) ), then
options[:do_bad_stuff] is 0, which is *not* false, and so the "if"
statement will inadvertently execute.
-glenn
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