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Showing posts from 2019

Type Conversion in Rust

Type conversion is not special in Rust. It's just a function that takes ownership of the value and returns the other type. So you can name convert functions anything. However, it's a convention to use as_ , to_ , and into_ prefixed name or to use from_ prefixed constructor. From You can create any function for type conversion. However, if you want to provide generic interfaces, you'd better implement the From trait. For instance, you should implement From<X> for Y when you want the interface that converts the X type value to the Y type value. The From trait have an associated function named from . You can call this function like From::from(x) . You also can call it like Y::from(x) if the compiler cannot infer the type of the destination type. Into From have an associated function, it makes you be able to specify the destination type. It's why From has an associated function instead of a method, but on the other hands, you cannot use it as a me

Do not use garbage collection to catch memory leak

Garbage collection is a technique that automatically releases unnecessary memory. It's very famous because many programming languages adopted garbage collection after John McCarthy implemented it in Lisp. However, there are a few people who misunderstand what garbage collection does. If you think garbage collection prevents a memory leak, unfortunately, you are one of them. Garbage collection cannot prevent a memory leak. There is no way to avoid all memory leaks if you are using Turing-complete language. To understand it you should know what a memory leak is. Wikipedia describes a memory leak as the following: a type of resource leak that occurs when a computer program incorrectly manages memory allocations in such a way that memory which is no longer needed is not released. Briefly, a memory leak is a bug that doesn't release a memory that you don't use. So it is first to find the memory which will not be used in order to detect memory leaks. Unfortunately, it i