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What are free monads?

...ll x) = Roll (fmap (fmap f) x) --this is the same thing as (++) basically concatFree :: Functor f => Free f (Free f a) -> Free f a concatFree (Pure x) = x concatFree (Roll y) = Roll (fmap concatFree y) instance Functor f => Monad (Free f) where return = Pure -- just like [] x >>...
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Can overridden methods differ in return type?

... class Alpha { Alpha doStuff(char c) { return new Alpha(); } } class Beta extends Alpha { Beta doStuff(char c) { // legal override in Java 1.5 return new Beta...
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Can hash tables really be O(1)?

...TW - concrete example - Visual C++'s std::hash of textual keys combines 10 characters evenly spaced along the text into the hash value, so it's O(1) regardless of text length (but massively more collision prone than GCC!). Separately, claims of O(1) have another assumption (normally correctly) that...
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Smart way to truncate long strings

...rd" and "soft" limits, like, for example, if the string is longer than 500 character, truncate it to 400. This may be useful, when the user wants to see the whole text and clicks some link for it. If, as a result, you load just 1 or 2 chars more, it will look really ugly. – Max...
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What exactly is nullptr?

...ranteed to be 0. It can be 0L, in which case a call to void f(int); void f(char *); will be ambiguous. nullptr will always favor the pointer version, and never call the int one. Also note that nullptr is convertible to bool (the draft says that at 4.12). – Johannes Schaub - lit...
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How to pattern match using regular expression in Scala?

... Some(p.Jo.StartsWith(fn)), Some(p.`.*(\\w)$`.Regexp(lastChar))) => println(s"Match! $fn ...$lastChar") case _ => println("nope") } } share | improve this answer...
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C#: Printing all properties of an object [duplicate]

... string) return string.Format("\"{0}\"", o); if (o is char && (char)o == '\0') return string.Empty; if (o is ValueType) return (o.ToString()); if (o is IEnumerable) return ("..."); return ("{ }"); } } ...
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Copy a file in a sane, safe and efficient way

...ing with the file system: #include <copyfile.h> int copyfile(const char *from, const char *to, copyfile_state_t state, copyfile_flags_t flags); share | improve this answer | ...
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Understanding recursion [closed]

.... We'll use a binary tree of nodes, but this time the value held will be a character, not a number. Our tree will have a special property, that for any node, its character comes after (in alphabetical order) the character held by its left child and before (in alphabetical order) the character held ...
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How to define an enumerated type (enum) in C?

...um { RANDOM, IMMEDIATE, SEARCH } strategy = IMMEDIATE; int main(int argc, char** argv){ printf("strategy: %d\n", strategy); return 0; } If instead of the above, the second line were changed to: ... enum { RANDOM, IMMEDIATE, SEARCH } strategy; strategy = IMMEDIATE; ... From the warnings, ...