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Is a statically-typed full Lisp variant possible?
...te, let's take a look at the list structure itself, called the cons, which forms the primary building block of Lisp.
Calling the cons a list, though (1 2 3) looks like one, is a bit of a misnomer. For example, it's not at all comparable to a statically typed list, like C++'s std::list or Haskell's ...
Can every recursion be converted into iteration?
...e a programming system so advanced as to treat a recursive definition of a formula as an invitation to memoize prior results, thus offering the speed benefit without the hassle of telling the computer exactly which steps to follow in the computation of a formula with a recursive definition. Dijkstra...
Index on multiple columns in Ruby on Rails
...at the beginning. i.e. if you index on [:user_id, :article_id], you can perform a fast query on user_id or user_id AND article_id, but NOT on article_id.
Your migration add_index line should look something like this:
add_index :user_views, [:user_id, :article_id]
Question regarding 'unique' ...
Why are empty strings returned in split() results?
...to be equal to ['segment', 'segment'] is reasonable, but then this loses information. If split() worked the way you wanted, if I tell you that a.split('/') == ['segment', 'segment'], you can't tell me what a was.
What should be the result of 'a//b'.split() be? ['a', 'b']?, or ['a', '', 'b']? I.e., ...
Parcelable where/when is describeContents() used?
...ace
Implementing multiple inheritance by rules defined in human readable form? :-)
It seems like C++ programmer designed Parceable and at some point he realized: Oh, damn, there is no multiple inheritance in Java... :-)
s...
How to write to a JSON file in the correct format
...reating a hash in Ruby and want to write it to a JSON file, in the correct format.
4 Answers
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Turn off Chrome/Safari spell checking by HTML/css
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for all elements of a form it is possible and so:
<form spellcheck="false" .. />
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What is the difference between IQueryable and IEnumerable?
...om query logic it receives, e.g., a predicate or value selector, is in the form of an expression tree instead of a delegate to a method.
IEnumerable<T> is great for working with sequences that are iterated in-memory, but
IQueryable<T> allows for out-of memory things like a remote data s...
How to create a GUID/UUID in Python
How do I create a GUID in Python that is platform independent? I hear there is a method using ActivePython on Windows but it's Windows only because it uses COM. Is there a method using plain Python?
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How does Java handle integer underflows and overflows and how would you check for it?
...^ (left - right))) < 0;
}
}
(you can substitute int by long to perform the same checks for long)
If you think that this may occur more than often, then consider using a datatype or object which can store larger values, e.g. long or maybe java.math.BigInteger. The last one doesn't overflow,...