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Why is there “data” and “newtype” in Haskell? [duplicate]
It seems that a newtype definition is just a data definition that obeys some restrictions (e.g., only one constructor), and that due to these restrictions the runtime system can handle newtype s more efficiently. And the handling of pattern matching for undefined values is slightly different.
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Check if object is file-like in Python
...objects in Python that behave like a real file, e.g. have a read() and a write method(), but have a different implementation. It is and realization of the Duck Typing concept.
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Why is “throws Exception” necessary when calling a function?
...o specify a throws clause for all classes. Specifically, classes that are either an Error or RuntimeException or any of the subclasses of these two. In your case Exception is not a subclass of an Error or RuntimeException. So, it is a checked exception and must be specified in the throws clause, if ...
Collection versus List what should you use on your interfaces?
...s to why not List<T>, The reasons are future-proofing and API simplicity.
Future-proofing
List<T> is not designed to be easily extensible by subclassing it; it is designed to be fast for internal implementations. You'll notice the methods on it are not virtual and so cannot be overridd...
Where is the C auto keyword used?
... about the auto keyword and in the course of time I actually forgot what it is. It is defined as:
9 Answers
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Should I pass a shared_ptr by reference? [duplicate]
...general, you should pass the shared pointer as a straight copy. This gives it its intended semantics: Every scope that contains a copy of the shared pointer keeps the object alive by virtue of its "share" in the ownership.
The only reason not to always pass by value is that copying a shared pointer...
Why does C++11's lambda require “mutable” keyword for capture-by-value, by default?
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It requires mutable because by default, a function object should produce the same result every time it's called. This is the difference between an object orientated function and a function using a global variable, effectively...
Setting the correct encoding when piping stdout in Python
...thon program, the Python interpreter gets confused about encoding and sets it to None. This means a program like this:
10 A...
What is the difference between bottom-up and top-down?
...r answers said that "bottom-up is memoization" ("assume the subproblems"), it may be the inverse (that is, "top-down" may be "assume the subproblems" and "bottom-up" may be "compose the subproblems"). Previously, I have read on memoization being a different kind of dynamic programming as opposed to ...
Generating PDF files with JavaScript
... into PDF files from a web page and I was hoping I could do this entirely within JavaScript. I need to be able to draw text, images and simple shapes. I would love to be able to do this entirely in the browser.
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