Developers Club geek daily blog

The personal Web server on Wolfram Language

3 years, 3 months ago
Sometimes people want to make quickly the Web server which root logic will be on Wolfram Language. There is the correct and long way. The beauty of solution and productivity will be award. Also there is the second way. We will also talk about it.

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Message broker for service architecture on the basis of ZMQ? or rest of the developer

3 years, 3 months ago


The strong wind blew in vessel board. Small splashes and drops of rain forced slightly unshaven face under points squints. It was not simply cold: the cold got everywhere. Under jacket, trousers. Hands grew dumb with it and blood stiffened. But the seaman knew that somewhere there behind the cape there is quiet island on which it is possible to wait bad weather.
The coast has met the exhausted crew by noise of trees and whisper of canes. People knew that they have only days to have a rest, be washed and continue fight against elements.

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The first in the history of ReactOS Hackfest

3 years, 3 months ago
We hurry will share important information. First in the history of ReactOS to hakfest to be! Action will take place from August 7 to August 12, 2015 in the city And? Hen (Germany). Everyone is invited.

All information on event can be received on special viki-page.

image
The photo from similar action of GNOME WebKitGtk + Hackfest

The city of Aachen is located in place where Germany is closed with Belgium and the Netherlands, in 4-5 km from borders with these countries. To the South from the city the national park Eyfel begins. Open for yourself the most western city of Germany. In historic center of the city, Aachen suggests to taste at the same time spirit of the scientific environment with opportunity to estimate huge variety of pubs. Let's catch this atmosphere and we will kodit week without a break, that in command to achieve worthy results!

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AOP or how to write the bicycle for analytics

3 years, 3 months ago
image
In large projects, at implementation of logic of tracking of events, often rise before problem of pollution of code calls of methods of tracking, inconvenience of explicit object linking to events and support of these events at change of models or ui of behavior.

Because of the above described reasons, has come to my mind to write the solution which of course, will not leave further my git of repository and this article.

Who is not afraid of reflection and slow code? I ask under kat.

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Interesnosti from the world of kvayn (100 languages, radiation and steady, hours, snake)

3 years, 3 months ago
image

Relay from 100 programming languages


Kvayn? the computer program which issues the exact copy of the source text on output. Chain kvayn differs from normal in that on each subsequent iteration the code in other programming language until the code of original kvayn is displaid is displaid. In the middle of 2013 the Japanese programmer Yusuke Endo (????) has developed chain kvayn, containing 50 programming languages. At the end of 2014 codes it has published the new version including already 100 languages!

Source codes and information on compilation of all these kvayn are on gitkhaba: quine-relay. It is curious that the source code in the form of the picture has been written not in manual (that is impossible in principle), and generated. The author notes that within year he will publish the book about obfustsirovanny programming which will include detailed explanation how to write kvayna, kvayna ascii-art, chain kvayna (similar to this relay).

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We do house farm for rendering of video

3 years, 3 months ago
In this article I will tell about the experience of creation of the separate server (? farm? it is painfully loudly told) for rendering of video in house conditions.




It is known that the renedering of video and three-dimensional images takes a lot of time and many resources of the computer demand. Memoirs are still fresh as being the student I put for the night the buzzing computer with the started assembly program of the movie, and for the morning it appeared, something was not enough place on the hard drive, or something has forgotten to add to roller and everything had to be started anew. Now true professionals do this operation far off. For example, the director James Cameron during shooting? Avatar? especially for himself has made the order for creations of the whole data-center in which renderings of scenes were started. I am still not so cool to build the separate data-center, but idea of that this operation could be started separately on other server haunted me long time.

Second problem? it is mounting of the video. In spite of the fact that modern computers become more powerful, development of video cameras too does not stand still and the turned-out videos files become heavier and heavier. And, as a result, becomes problematic to process them. When you mount the long movie, track preview with the imposed filters and transitions starts podgruzhat the processor and the image starts lagat, doing creative process of mounting tiresome. From this that I tried, the most productive was iMovie that is preset on all Poppies. Even the movie lasting 45 minutes could be edited without special problems on rather low-power makbuk. It was possible to use any filter and to see result in preview window without any logs. So owners of poppies were lucky here. One minus at iMovie: during operating time it starts consuming unreasonable quantity of disk space. Probably, it is connected with aggressive caching for editing and preview.

In this article I will describe the experience as I tried to solve these two problems of mounting and rendering on the example of home video of roller.

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Creation of the elementary data structures by means of functions in Python

3 years, 3 months ago
Introduction: In the summer before last I have opened for myself the magnificent book SICP — reading only the first section of the book has opened for me the new world of functional programming. Anonymous functions, functions that functions, functions of the higher orders return. Authors have shown in the second section of the book that it is possible to create by means of only one functions different data structures, such as couple, the list, or even trees! Today I would like to implement some ideas from this book in the Python programming language. Of course, only by means of functions.

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Seven surprising "opportunities" of Javascript

3 years, 3 months ago
For the last some months I have made some completions for JSHint, generally with the purpose to study ES6 (I especially am proud of how detection of areas of visibility for variables is redone). During this process I have come across some things which have surprised me — generally in ES6, however there is also something about ES3 that I never used before.

Break from any block


For certain you know that in any cycle it is possible to use key word break and continue — it is standard opportunity in the modern languages of programming. However not all know that cycles can give tags and with their help to interrupt any specific cycle:

outer: for(var i = 0; i < 4; i++) {
    while(true) {
        continue outer;
    }
}

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Use of monads in With ++. Part 2: status monad

3 years, 3 months ago
Part 1
Part 2

What will you make if tomorrow win in lottery? Buy sports car, will give up work and will go to tour across the USA? And can be will become the founder of home company, will increase status and buy the personal airplane?

All of us like to do plans, and most often they lean on our financial status. Such plans can be described by function. For example, plan of purchase of a car it:

pair<Car, Cash> buyCar(Cash cashIn)


On input at us quantity of money (Cash), and on output the brand new machine (Car) and some quantity (not the fact that the positive!) the remained finance (Cash). Generally, the financial plan — is function which accepts money and returns result, plus the remained quantity of money. It can be described by template:

template<class A>
using Plan = function<pair<A, Cash>(Cash)>;


You can integrate small plans to receive the big. For example, you can start up the funds for the trip which have remained after purchase of a car or invest in business. If you have things already belonging to you, they can become part of your plans:

template<class A>
Plan<A> got_it(A a)
{
    return [a](Cash s) { return make_pair(a, s); };
}


What relation all these dreams have to solution of our puzzle? Earlier I said that we need to save somewhere status, and it is way as which programmers in functional languages work with status. Instead of explicit modifying of status they write code which generates the plan of action.

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Use of monads in With ++. Part 1: list monad

3 years, 4 months ago
Part 1
Part 2

Sometimes programmers on With ++ ask to give example of task which cannot be solved without use of monads. Let's begin with that this question is incorrect in itself — it all the same what to ask, whether there is task which cannot be solved without cycles. It is obvious if in your language there is support of the operator goto, you can do without use of iteration statements. That monads (and cycles) can make for you, it to simplify your code and better to help to structure it. As use of cycles turns spaghetti code in normal, and use of monads can turn your code in imperative style into the declarative. This transformation can easier help to write, understand, support and expand your code.

Well and here to you problem which can get on interview. It is not absolutely trivial, some approaches to solution and the best of them are possible not at once are obvious — just over what it is worth thinking.
The following puzzle is offered to you:

  s e n d
+ m o r e
---------
m o n e y


Each letter corresponds to digit from 0 to 9. It is necessary to write the program which will pick up such compliances that the written addition operation was correct. Before continuing reading article — think minute, as if you have solved this problem?

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