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How can I build a small operating system on an old desktop computer? [closed]
...in, as I know writing an operating system is unbearably complicated (especially by oneself).
20 Answers
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Why Func instead of Predicate?
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Well, actually you have to place that in the context of the guideline, which is about writing a LINQ provider. So yeah, for LINQ operators, the guideline is to use Func<> and Expression<> as parameters for the extension met...
Python (and Python C API): __new__ versus __init__
...vs immutable types.
__new__ accepts a type as the first argument, and (usually) returns a new instance of that type. Thus it is suitable for use with both mutable and immutable types.
__init__ accepts an instance as the first argument and modifies the attributes of that instance. This is inappropr...
When to use the different log levels
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I generally subscribe to the following convention:
Trace - Only when I would be "tracing" the code and trying to find one part of a function specifically.
Debug - Information that is diagnostically helpful to people more than just...
Re-raise exception with a different type and message, preserving existing information
...ns that it can raise (e.g. inheriting from a FooError abstract class for all the foo module's specific exceptions). This allows users of the module to catch those particular exceptions and handle them distinctly, if needed. But many of the exceptions raised from the module are raised because of ...
How to send a “multipart/form-data” with requests in python?
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Basically, if you specify a files parameter (a dictionary), then requests will send a multipart/form-data POST instead of a application/x-www-form-urlencoded POST. You are not limited to using actual files in that dictionary, howe...
Using Java 8's Optional with Stream::flatMap
...latMap(Optional::stream)
.findFirst();
Java 8
Yes, this was a small hole in the API, in that it's somewhat inconvenient to turn an Optional<T> into a zero-or-one length Stream<T>. You could do this:
Optional<Other> result =
things.stream()
.map(this::resolv...
What is Hindley-Milner?
...er system is that each well-typed term has a unique "best" type, which is called the principal type. The principal type of the list-length function is "for any a, function from list of a to integer". Here a is a so-called "type parameter," which is explicit in lambda calculus but implicit in most ...
Why use symbols as hash keys in Ruby?
...saves memory, because they are only stored once.
Symbols in Ruby are basically "immutable strings" .. that means that they can not be changed, and it implies that the same symbol when referenced many times throughout your source code, is always stored as the same entity, e.g. has the same object id...
What's the difference between Ruby's dup and clone methods?
..., name: "Favorites">
clone creates a new object with the same id, so all the changes made to that new object will overwrite the original record if hitting .save
category2 = category.clone
#=> #<Category id: 1, name: "Favorites">
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