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  Five-minute Multimethods in Python

So what are multimethods? I'll give you my own definition, as I've come to understand them: a function that has multiple versions, distinguished by the type of the arguments. (Some people go beyond this and also allow versions distinguished by the value of the arguments; I'm not addressing this here.) As a very simple example, let's suppose we have a function that we want to define for two ints, two floats, or two strings. Of course, we could define it as follows: def foo(a, b): if...

   Python,Multimethod,Argument list,Version,Overloadding     2011-12-07 08:41:03

  Haskell’s effect on my C++: exploit the type system

Like most programmers, I was attracted to Scheme by the promise that it would make me a better programmer. I came to appreciate the functional style, but swapped to Haskell, a more developed language with a rapidly developing standard library. Unfortunately, for me, Haskell can’t yet replace C++ on a day to day basis, so I reluctantly spend my days tapping away at C++. So, were the promises true? has functional programming made me a better programmer? Better is a tough question,...

   Haskell,C++,Type system,Comparison     2012-02-06 07:44:35

  The ugliest C feature:

<tgmath.h> is a header provided by the standard C library, introduced in C99 to allow easier porting of Fortran numerical software to C. Fortran, unlike C, provides “intrinsic functions”, which are a part of the language and behave more like operators. While ordinary (“external”) functions behave similarly to C functions with respect to types (the types of arguments and parameters must match and the restult type is fixed), intrinsic functions accept arguments of...

   C,,Fortran,Intrinsic functions,C99,Ugly     2011-12-26 08:33:27

  Python object creation sequence

[The Python version described in this article is 3.x] This article aims to explore the process of creating new objects in Python. As I explained in a previous article, object creation is just a special case of calling a callable. Consider this Python code: class Joe: pass j = Joe() What happens when j = Joe() is executed? Python sees it as a call to the callable Joe, and routes it to the internal function PyObject_Call, with Joe passed as the first argument. PyObject_Call looks at the ty...

   Python,Object creation     2012-04-16 15:03:55

  What is the use of empty struct in GoLang

In Go, an empty struct struct{} is a struct with no fields that may appear to be of little use, but in reality, it can be useful in certain situations and become a simple and efficient solution in code. As a semaphore or lock Because the empty struct has no fields, it can be conveniently used to implement some concurrency control functions, such as mutex locks, read-write locks. We can use chan struct{} to implement an unbuffered channel for controlling concurrent access. package main import ( ...

   GOLANG,EMPTY STRUCT     2024-04-05 23:54:03

  How many bytes a boolean value takes in Java?

Have you ever wondered how many bytes a boolean value takes in Java? One byte, this might be the answer comes out of your mind right away. But is it? Let's dig in more. Per Oracle documentation on boolean value definition, there is below statement: boolean: The boolean data type has only two possible values: true and false. Use this data type for simple flags that track true/false conditions. This data type represents one bit of information, but its "size" isn't something that's precisely defin...

   JAVA,INTERVIEW,SIZE,BOOLEAN     2020-02-29 02:49:18

  Why no max/min function for integer in GoLang

You may notice that there is no max/min function provided to compare the maximum/minimum of two or more integers if you are a GoLang developer with some experience . In other languages, these functions are provided as part of the core lib functions. Have you wondered why?  Indeed GoLang provides max/min function in math package, but they are used for comparing float64 data type. The signature of these two functions are math.Min(float64, float64) float64 math.Max(float64, float64) float...

   GOLANG,MAX,INT,INT64     2019-06-08 07:00:55

  Set Theory in C++11

Have you ever felt the need to perform set theoretic operations on types? Not really? Me neither, but I thought it’s a fun thing to try out. So, if you ever feel the need of using type sets, C++11 makes it quite easy to do so. Especially variadic templates allow for a much more condensed syntax compared to type list constructs formerly used. (Disclaimer: This is rather a proof of concept, but maybe somebody comes up with a useful scenario.) Let’s start by d...

   C++,set theory,Math     2012-03-11 13:15:55

  Restore mocked variables in GoLang unit test

One of the guarding principles of writing unit test is that there should be no real external calls for dependant services. Unit test should run by its own and can run without issues on any environment including local, build, test environment. This indicates there should be some mock responses whenever an external call is needed so that different unit test scenarios can be covered. How can this be done in GoLang? In GoLang, anything can be assigned to a variable even including functions. A variab...

   GOLANG,UNIT TEST,MOCK FUNCTION,RESTORE MOCK     2021-12-10 20:43:00

  Load and execute JavaScript

When we load and execute JavaScript in a webpage, there are many points we need to care about because of its design and feature. There are two features about JavaScript execution in a browser: 1). The JavaScript codes will be executed immediately once loaded;2). When JavaScript codes are being executed, they will block the following contents (including page rendering and other resources downloading). So if there are multiple js files to be loaded, these codes will be executed sequentially. Since...

   JavaScript,async,defer,load,execute     2013-06-07 04:53:46

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