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SEARCH KEYWORD -- Code writing

  A Perl Regular Expression That Matches Prime Numbers

perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' Can you figure out how it works? I give an explanation below, but try to figure it out yourself. Here is what happens when you run it: $ perl -lne '(1x$_) =~ /^1?$|^(11+?)\1+$/ || print "$_ is prime"' 1 2 2 is prime 3 3 is prime 4 5 5 is prime 6 7 7 is prime 8 9 10 11 11 is prime Here is how it works. First, the number is converted in its unary representation by (1x$_). For example, the number 5 gets converted into 1x5, which is ...

   Perl,Regex,Regular expression,Prime number,One line     2011-12-26 08:42:00

  Some lovely software design quotes

  Every time when I read technical books, I like reading the quote of a famous person at the start of a chapter(if any), usually they are very interesting. Here is a collection of famous quotes. Life’s too short to build something nobody wants – Ash Maurya, Running Lean author Give someone a program, you frustrate them for a day; teach them how to program, you frustrate them for a lifetime. – David Leinweber There are two ways of constructing a software design: One way is...

   Quote,Software design     2012-10-13 09:13:34

  HeartBleed: Should C be blamed for the HeartBleed bug?

There is a discussion about the security of applications written in C on Hacker News recently after the report of HeartBleed bug in OpenSSL. In this discussion, some people are saying that the applications written in C are unsafe. It seems all or most of the faults should be laid on C. I think this is biased. The language itself should not be blamed.Safety is a relative term for programming languages. No language is absolutely safe. We claim some languages like Java and C# are safer than C/C++ b...

   C,HeartBleed,Analysis,Code review     2014-04-14 03:52:55

  Learning Ruby and Ruby vs Lisp

The company I work for has a lot of legacy Ruby code, and as Ruby has become kind of a mainstream language, I decided to get a book about it and learn how it works. As my learning resource, I chose The Ruby Programming language by David Flanagan and Yukihiro Matsumoto as that receives great customer reviews, covers Ruby 1.8.7 and 1.9 and is authoritative because the language creator is one of the authors. The book makes a good read in general. There are plen...

   Ruby,Feature,Functional,OOP,Lisp,Difference     2011-12-12 07:42:01

  Text editor vs IDE

A meaningless editor war Many people like to debate which editor is the best. The biggest controversy is between Emacs and vi. vi supporters like to say: "Look it's very fast to type in vi, our fingers no need to leave the keyboard, we even no need to use the up,down,left and right keys" Emacs supporters often downplayed this and said: "What's the use of typing fast if I just need to press one key and it equals to dozens keys you type in vi?"In fact, there is another group of people who like to ...

   Editor,IDE,Structured editor,vi     2013-05-20 12:03:39

  Why Lua

In this article, I would like to discuss why you should use Lua. This all started with a message that recently popped up on the Lua mailing list regarding why isn't Lua more widely used? The answers went from randomness to lack of libraries to a variety of other things, but the one that resonated with me most was that there are fewer people who enjoy the do it yourself approach, which Lua fully embraces. I've come to think of Lua as the Arch Linux of programming languages. Which, almost by d...

   Lua,Feature,C,Simple,Portable     2012-02-27 04:58:15

  The Book That Every Programmer Should Read

No, it’s not Knuth’s “The Art of Programming”. I’m talking about quite an easy-to-read (compared to TAoP) book, which, in fact, does not require any engineering or mathematical background from the reader.I am talking about C. Petzold’s “CODE”. It is a truly remarkable book about how computers work. Let me explain why I think this book is so awesome.The book starts from the very beginning, from explaining what code is, bringi...

   Programmer,Book,Must read,CODE,C. Petzold     2011-10-31 10:43:58

  Why is single threaded Redis so fast

Redis is a high-performance, in-memory key-value database. According to official test reports, it can support around 100,000 QPS (queries per second) on a single machine. However, Redis uses a single-threaded architecture in its design. Why does Redis still have such high performance with a single-threaded design? Wouldn't it be better to use multiple threads for concurrent request processing? In this article, let's explore why Redis has a single-threaded architecture and still maintains its spe...

   REDIS,SINGLE-THREADED,MULTI-THREADING     2023-02-28 05:16:22

  JavaScript programming style

Douglas Crockford is a JavaScript expert, he is the inventor of JSON. In November 2011 he made a speech "Youtube", during the speech he talked about what JavaScript programming style is.I recommend this speech to everyone, it not only helps you learn JavaScript but also make you enjoying because Crockford is very humorous and he made audience laugh frequently.Next I will summarize JavaScript programming style according to this speech and his article code convention. The so-called programming ...

   JavaScript, programming style,Curly braces,Equal     2015-10-14 10:16:44

  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

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