Why Flutter is So Special?
25 July, Number of Words - 1276, 6 min Read
|
|
First of all let’s introduce you to flutter because most of the people around me keep wondering what is
the main difference between Flutter and Dart, so if you have this confusion I would definitely say that
you have come to the right place. If you have any doubts regarding whether to start app development
using Flutter or not you are at the right place. So without giving your eyes extra pain lets start.
Introduction-:
Let’s start with the keypoint i.e. “Flutter vs Dart” , so in short Flutter is the Software Development
Kit that is used for making the cross-platform apps and Dart is the programming language that is used to
code these apps, in easier words Flutter is just like the tools which we use for the construction of the
house and the material which we use can be somewhat compared to Dart.
Now coming to the real official definition of Flutter and Dart , So Flutter is Google’s UI toolkit for
building beautiful, natively compiled applications for mobile, web, desktop and embedded devices from a
single codebase. Now Dart is a programming language designed for client development, such as for the web
and mobile apps. It is developed by Google and can also be used to build server and desktop
applications. Dart is an object-oriented,class-based, garbage-collected language with C-style syntax.
Well, now we have it. And I want to share the joy of working on Flutter with you, so that you make the
most benefit of the innovation. In this article, I highlight my thoughts on what advantages of Flutter
are going to make it dominate cross-platform application development in the upcoming years.
Details-:
• Pros of using Flutter-:
1. Cross-Platform support -: The biggest advantage of using
Flutter for the purpose of app development is
that you no longer need to know 3–4 languages for the purpose of setting up your app and web app.
Since Flutter is cross-platform ,therefore we can code a single code snippet according to the need and
that is it, we can use the same code to run ios apps, android apps and web apps also.
In brief, sharing the UI and business logic, which is possible with Flutter, saves time, effort and the
health of the developer while not affecting the performance of the end product.
2. Code development time got reduced-: Flutter’s “hot reload”
feature, in turn, allows seeing the applied changes almost instantly, without even losing the current
application state. And this is exactly what makes Flutter app development several times faster due to the
increased development speed.
Besides, the Flutter team has put lots of effort into providing a wide variety of ready-to-use widgets. Most
of them are incredibly customizable, saving your time like no other framework before. In addition to
numerous core layout widgets, Flutter provides a large set of Material and Cupertino widgets that perfectly
mimic the behavior of each design language.
3.
Libraries and Packages that Dart provides-: If someone needs
to implement some extra features in the app then he/she does not want to waste his/her time writing the full
code again and again there are thousands of packages that are available on
https://pub.dev/ where you can search for the package you want to embed in your code.
All we need to do is just a little research to find the appropriate package name and that can easily be done
using stackoverflow and other informative resources.
4. Works easily on both Android Studio and VS Code-: While most
of us prefer coding on VS Code instead of any other compiler but most of the flutter engineers prefer
Android Studio due to the next level features that it provides such as AVD Manager,Instant App Run,help to
Build Up App using intellij-code for All Devices and also helps to Connect with Firebase but apart from all
of this Android Studio is a very heavy software which is ultimately going to heat up your device if its not
having enough RAM and SSDs so many of the developers face problems but there is no need to worry as setting
up flutter on VS Code is also possible just using few extensions. (P.S.-: You can also refer to a youtube
tutorial if you want to)
5. Documentation-: Keeping the best part for the last ,the
biggest advantage of using flutter is its documentation. All of the flutter widgets used in the code are
very well documented and you may find it very easily on its official website. Easy documentation helps you a
lot to go through the errors and the use of any widget in flutter.
• Cons of using Flutter-:
So now after so many advantages of flutter let’s look at the other side of the coin,also all the cons listed
below are according to me which obviously means that it depends on user to user. But while using flutter i
faced the following drawbacks-:
1. Small Community-:Although flutter is growing at a very fast
pace but still it has a smaller community in comparison to the community of other coding languages used for
app development i.e. Java, Kotlin, Swift.
So lets say if you have a doubt/error that is very much conceptual/uncommon there is a slight possibility
that you may find it difficult to find the solution.
2. Developing Stage-:Although we can see this as an advantage
that flutter is developing continuously but sometimes it feels annoying to work with flutter due to its
regular updation. Let’s assume you are working on a project and taking help from a tutorial so even if the
tutorial is just six months old but it can easily happen that flutter got updated and now the widget is
known by other name or may be the widget shown in the video is deprecated (P.S. It happens only sometimes)
all of this breaks the continuity of the project we are working on because we need to search what is the
newly updated name by reading all of the documentation.
3. Clashing of dependencies-:We import packages in flutter
through passing of the installation command in pubspec.yaml file but it may happen sometimes that two
different libraries may not be ready to share their latest versions together as one or the other hasn’t been
updated after it was coded by the authors. So we need to change the versions accordingly.
•Conclusion from my side-:
Time being it may doubt many of you that whether we should start with flutter or not but according to my
recommendation with the time passing and the growth rates flutter is the future of app development as it is
way more crisp then all the other languages and easy to learn and also due to its continuous development.
P.S. If you are very much interested in app development dont just remain limited to flutter, open up to
kotlin,java and swift also because it will increase the possibility of you getting to know app development
from depth.
So according to me at the end just hold your laptop and make a coffee and start coding for 45 days or so
continuously on flutter and you will definitely learn to code flutter to the mark of what is really required
to build basic to medium level applications.
Hope I was able to give you a brief idea about what flutter is and why it is growing so fast and what are
the expectations which we can have with flutter in the upcoming years and also the main point whether we
should start flutter or not.
THANK YOU
ESHAN GUPTA


ENVS615
| Dani Arribas-Bel
Accidental data (Arribas-Bel, 2014)
Lazer & Radford (2017)
Data, in itself, is not very useful… insights are
GDS1
: Data Gathering, Preparation, and ExplorationGDS2
: Data Representation and TransformationGDS3
: Computing with DataGDS4
: Data Visualisation and PresentationGDS5
: Data ModelingGDS6
: Science about Data Science
“Data, data, data” by Dani Arribas-Bel is licensed under a Creative Commons Attribution-ShareAlike 4.0 International License.


Coming from an architecture background the house analogy is one I find quite relatable.
HTML is the overall structure of the website/house. For instance when you arrive at house the homepage might be the foyer. From the homepage you might have a menu bar which is analogous to the hall way or circulation around the house. Different rooms/pages will have different sizes and performance requirements that is dependent on what you need.
CSS is what we might call the look and feel. In the house/website what is the carpet/font is it wool/shag pile/storm colored. So CSS allows you to go into detail into what the stuff looks like.
DOM I find more complex - I feel like it is the thing that is interpreting the HTML and making it happen - So a foundation, a design or even a contractor who is constantly building the house is a good analogy.
Boxifying the design is a process breaking down a design to its smallest constituent parts so that can be built using html elements.
The box model is the amount of space an element might take up. There is a margin, border, padding and then the actual content. You can adjust all of these parts to ensure that content displays as you would like it to.


Isar735.github.io
20% Off Chegg Coupons Coupon Codes - November. Today's top Chegg coupon: 4 Week Free Trial of Chegg Study. Find 22 Chegg promo and coupon codes for November 2018 on RetailMeNot. Free Stuff You Can Get As A College Student – The Leading. Real Ways to Earn. Work from home jobs and ways to make money online. Scam-free.
This page contains a list of all current Chegg coupon codes that have recently been submitted, Take $10 Off w/ Promo Code. 20% off Chegg Homework Help Annual.
11 Sites That Pay You To Be An Expert Chegg Reviews - 123 Reviews of Chegg.com Sitejabber.
Chegg does not currently offer a coupon to Chegg Study. Don t know what Chegg Study is? Learn more here. Looking to save money on textbooks. Score sat essays online Coupon Code For Chegg Homework Help pay someone to do your essays help me create a business. Chegg Promo Code Chegg is not only a great place for . Chegg Promo Code, Deals Discount codes 2018. . you can also get Chegg’s homework help free which
Chegg Coupon Promo Code Offers - BrokeScholar. Chegg Coupons Promo codes - DontPayFull.com.
Amazon provides a student account free for the first six months. You get free two-day shipping on many of the products on Amazon. After six months Details: Try a 4-week Free Trial of Chegg Study with your textbook purchase or rental and get expert help with your assignments. Create a Chegg account Find all the Chegg coupons and promo codes you'll need to get free shipping and save on textbooks, tutoring, test prep, and more at Groupon Coupons! Visit Chegg Coupons, Promo Codes Deals 2018 - Groupon. 123 reviews for Chegg, 2.0 stars: "I ordered a textbook from Chegg and they sent me an empty package. Then, they sent me a textbook on CD which was not what I ordered. Chegg Coupons: Coupon Codes, Promos 2018 - RetailMeNot.
About The Company: Chegg is a great place for college students. They provide book rentals, 24/7 online study help and homework support and the ability to make money. Students everywhere visit Chegg to find study aids, around-the-clock homework help and a large collection of textbooks for purchase and rental.
Chegg Coupons. 15 savers Expired and Not Verified Chegg Promo Codes You’ll also have the option to subscribe for live homework help from tutors and subject.
Chegg Promo Code, Deals Discount codes 2018 – Chegg Coupons.
Coupon Code For Chegg Homework. Books Coupons, Promo Codes Deals - November. Chegg.com Coupon Codes 2018 (50% discount) - November. Chegg Coupons - Free Trial of Study / Free Shipping on Books. This code offers you 20% on Chegg Homework Help Top Chegg Coupons Promo codes. Use of this Web site constitutes acceptance of the DontPayFull.com. Find all the Chegg coupons and promo codes Check out the section All your homework Connect with a live tutor for 24/7 help and get 30 minutes free with Chegg. Chegg Coupons :: All Active Discounts in October. Find and share books coupon codes and promo codes for great discounts at thousands of online stores. All Active Chegg Promo Codes Coupon Codes - Already redeemed 683 times Chegg offers 24/7 homework help online. Chegg Coupons – Free Trial of Study / Free Shipping on Books.


Fall 2018 Senior Design I
Electrical and Computer Engineering
Mississippi State University
Initial propsal of the project.
One page.
Contains Applications, Features, Specifications:
- Applications: how can this be used?
- Features: what can it do?
- Specifications: quantitative measures of what it can and cannot do, requirements for use.
Visually appealing, tells all in one page.
- Contains one or more graphics of product itself and usage of product in typical scenarios
Minimum length of two pages
Components:
- Introduction (why should I care?)
- Market and competitive product analysis
- Concise problem statement
- Implications of your success
Components:
- Technical Design Constraints
- Practical Design Constraints
- Engineering Standards
Design Definition with Synthesis and Analysis of Alternative Solutions Leading to a Decision
Summary:
- Functional Overview
- Theory & Background
- Synthesis of Design Options
- Analysis of Options
- Justification of Design Decision
- Detailed Design Description
The mid-semester design review is a checkpoint that reports on project progress to this point in the semester. At this presentation, any deficiencies that are documented must be rectified in your final design review. At this stage of the course, you will be expected to show solid design constraints, a preliminary design, and a comprehensive implementation plan.
One page.
The executive summary contains an overview of the problem,
an overview of the design constraints, an overview of the
approach you took to solve the problem, and an overview of
the novelty of your design.
The evaluation describes in detail the tests you have run to verify your design constraints and the results of those tests. I expect sections for each major subsystem and a section for system test.
Presentation goes over the technical aspects of the design as well as an overview of the prototype and how each element was tested.
Contains all of the previous documents.
Mid-semester update on the project.
Presentation goes over the technical aspects of the design as well as an overview of the prototype and how each element was tested.
Final Business Plan includes Business Plans 1, 2, 3, and 4.
Final Design Document includes all previous documents.


[Erowid Warning: Most Coricidin contains CPM (Chlorpheniramine Maleate) which can be dangerous in high doses. See DXM Brand Warnings for more info.]
Snipe:
had a hell of a trip last night, was staying over at a friend (Huxley) place for the evening and we planned a mostly quasi-legal drug night. We had a box of whip-its, 20+ grams of salvia, a half a gram of hash, 1 and 1 1/2 bottles of Robotussin Maximum Strength Cough syrup and a box of Coricidin (I know - bad idea, but I've done them plenty of times and wasn't worried about a single box) and were armed with my favorite smoking device, Bucks Bongy.
We left the local supermarket and I dosed 12 of the Coricidin (360 mgs of DXM and 52 mgs CPM) we arrived at his place some time later, I ate a small amount of chinese food and we smoked a bit of hash, did a few whippits and each had a salvia experience. Mine could be summed up as meeting his neighborhood of animals and whatnot and the crickets eventually saying all the noise animals made was more with telling us not to do away with them than interspecies communication.
Not long afterwards we decided to head into his pool and so we suited up and headed over with a small amount of whippits and balloons and the dispenser. Had a couple of interesting experiences; listening to noises under the water and a near birth experience that I aborted (no pun intended) by coming up for air a bit early - also one experiece of swimming through infinity and understanding the concept of such.
I then decided I wanted to put multiple nitrous containers into a single balloon - the nitrous tried to discourage this venture by the balloon coming off and my only being able to catch a third or so of the second cartrige in the balloon. I then proceeded to put three catriges in the balloon atop the third and ducked underwater with dispenser to my lips. I inhaled deeply held it for a moment and then released through my nose and took another inhalation off the balloon - with every passing second I moved the world I could feel farther away from me with my mind and at some point had the experience of standing up and moving around in someplace other dark - if there were other entities there maybe I could feel them but they made no attempts at contacting me. I stayed in this very dark place for some time and have difficulty remembering other details. I will now insert my friends accounting.
Huxley:
He put 3 cartregis in a balloon and went floating off to the dark side of the pool. I was just floatin around chillin when I thought 'Eh, it is possable that somethin bad could happen, so I better keep an eye on him'. I really did not think anythin was goin to happen, but I desided that I would count to 30 before checking on him. So I counted to thirty and he had still not come up from the water. I swam over and looked at him and he was litteraly layin on the bottom of the pool floor. I kept counting and nugged and kicked him with my foot too see if I could rouse him, but he did not rise.
At this I got conserned and lifted him out of the water so he could breath. I probebly counted to 40 or 50 before I got him out. I did not imeditly pull him to the edge, I just tryed to keep him floating so I could see if he was breathing. He was not (surprise surprise), so I started to pull him to the edge of the pool. I was pretty sure he was not totally dead yet cause his body was still light and did not feel like dead weight. I layed him on the concrete on the side of the pool, but had difficultly keeping him from falling back in. I checked his heart and it was still beating, that was a good thing, but I honestly belived his breathing was not there.
I only did it two or three times and then he started sputtering and, it seemed, minimel breathing. Then he started grunting and making the sounds of life. I was pretty happy at that. He layed there motionless for another couple of minutes, just breathing and making grunting sounds. Then after he layed down for a few, he got up and went inside with out a word. I was just glad with the way things turned out, as opossed to how they could have turned out.
Snipe:
I remember vaguely coming to at the side of the pool and the shorts I was wearing felt foreign and wrong. I got up and walked (half stumbled) over to what looked like a towel (I later saw it was quite dirty) dropped my shorts wrapped up and went inside to put my own clothing back on. Layed down for a bit, dropped another half bottle and ate some food - proceeded through the rest of the night relatively without incident.
I can say that this experience rattled my cage, though it probably didn't scare me as much as it could have/ should have. Today, the day after, I feel a bit weak (moreso than normal hangover from such drug experiences) and my chest hurts deep in my lungs. I wouldn't say I was putting this out as a deterent, merely to bring to people's attention that such things do happen and its always best to have a friend around for questionably dangerous journeys.
Experience Reports are the writings and opinions of the individual authors who submit them.
Some of the activities described are dangerous and/or illegal and none are recommended by Erowid.


s6-dns
Software
skarnet.org
The s6dns library interface
General information
libs6dns is a DNS client library, designed for clarity
and simplicity - which translates into smallness of the code.
A major focus of libs6dns is to avoid unnecessary use
of heap memory. Memory is only allocated in the heap to store
queries and response packets during a DNS resolution process, and
to store the final answers into a user-provided
stralloc; all the other operations use stack memory, and perform
as few copies as possible.
Compiling
- Make sure the s6-dns headers, as well as the skalibs headers,
are visible in your header search path.
- Use #include <s6-dns/s6dns.h>
Linking
- Make sure the s6-dns libraries, as well as the skalibs libraries,
are visible in your library search path.
- Link against -ls6dns, -lskarnet,
`cat $SYSDEPS/socket.lib` and
`cat $SYSDEPS/sysclock.lib`, $SYSDEPS being your skalibs
sysdeps directory.
Programming
The s6-dns/s6dns.h header is actually a concatenation of other headers:
the libs6dns is separated into several modules, each of them with its
own header.
- The s6-dns/s6dns-constants.h header provides constants used in
other parts of the library.
- The s6-dns/s6dns-ip46.h header provides an
abstraction for IPv4 and IPv6 transports.
- The s6-dns/s6dns-domain.h header provides
basic string manipulation primitives for domain names.
- The s6-dns/s6dns-message.h header provides
function to parse a message following the DNS protocol.
- The s6-dns/s6dns-engine.h header provides
the low-level asynchronous networking functions.
- The s6-dns/s6dns-rci.h header provides an
interface to resolv.conf reading.
- The s6-dns/s6dns-resolve.h header provides
the user-level synchronous resolution functions.
- The s6-dns/hosts.h header provides
functions to solve name and IP queries according the /etc/hosts file.
- The s6-dns/s6dns-fmt.h header provides
formatting primitives to display RR contents.
(User-level asynchronous resolution functions are provided in the
skadns library.)
Two functional macros are actually directly declared in the s6dns.h
header:
- Call s6dns_init() before all your s6dns operations.
s6dns_init() calls s6dns_rci_init(),
extracting resolv.conf information to an internal global
variable. The function returns 1 on success, and 0 (and sets errno)
on failure.
- Call s6dns_finish() when you're done with the libs6dns.
It frees the resources used.


Football: Bayern Munich part company with Kovac
BERLIN: German champions Bayern Munich have parted company with coach Niko Kovac, a day after a 5-1 thrashing away to Eintracht Frankfurt in the Bundesliga, the club said on Sunday (Nov 3).
A statement from Bayern said Kovac had gone after "mutual agreement" between him and the club, which dropped to fourth in the league after their heavy defeat.
Bayern president Karl-Heinz Rummenigge said: "The performance of our team in recent weeks and the results have shown us that there was need for action.
"I had an open and serious conversation with Niko on this basis on Sunday with the consensual result that Niko is no longer coach of Bayern."
Defeat by Eintracht was Bayern's second of the season but they have also drawn three matches.
"We all regret this development. I would like to thank Niko Kovac on behalf of FC Bayern for his work, especially for winning the double this past season," added Rummenigge.
Assistant coach Hans Flick will take charge of Bayern's Champions League clash with Olympiakos on Wednesday and for next Saturday's key clash with Borussia Dortmund.
Kovac, who took over at Bayern in 2018 after a spell in charge of Eintracht Frankfurt where he won the German Cup, said it was the "right decision".
"The results, and also the way we last played, made me come to that decision," he said.
"During this time, our team has won the championship, the DFB Cup and the Supercup. It was a good time. I wish the club and the team all the best."
Bayern have so far played a lacklustre season, lying in fourth place in the Bundesliga for their worst standing in 10 years and have conceded more goals than in any of the past decade at this stage.
While topping their Champions League group thanks to three wins, including a 7-2 demolition of Tottenham Hotspur, Bayern have not hit the form that has seen them dominate the league for the past seven seasons and win the 2013 Champions League crown.
Lacking any attacking plan they have largely relied on the goals from Robert Lewandowski to get them out of trouble with the Pole scoring 14 times in 10 league games alone.
They have been also been leaking goals despite a backline that includes French world champions Benjamin Pavard and now-injured Lucas Hernandez, while big close season transfer Philippe Coutinho has yet to shine in the Bundesliga.
Kovac had been brought in as an inexpensive option after a string of big-name predecessors, including Louis van Gaal, Jupp Heynckes, Pep Guardiola and Carlo Ancelotti.
German media have been speculating about a possible successor to Kovac for weeks, with Ajax Amsterdam coach Erik ten Haag seen as a possible target.


{% extends "base.html" %} {% block styles%} {{ super() }} {% endblock%} {% block content %}
Posted by {{pitch.user.name}}
Date: {{pitch.date}} at {{pitch.time}}
"{{pitch.content}}"
CATEGORY: {{pitch.category | upper}}


Defines the exponents used to obtain the limiting t85 parameters for Newtonian cooling.
int jmpSetNewtonianCoolingRange (int shortTimeExponent, int longTimeExponent);
shortTimeExponent [input]
Integer that specifies the exponent used to determine the minimum value of the t85 parameter range, calculated as a power of 10. Corresponds to the fastest cooling in the CCT calculation.
longTimeExponent [input]
Integer that specifies the exponent used to determine the maximum value of the t85 parameter range, calculated as a power of 10. Corresponds to the slowest cooling in the CCT calculation.
JMP_STATUS_OK |
Request has been successfully completed. |
JMP_STATUS_ERROR |
An error has occurred. |
| Headers | jmpcore.h jmpcct.h |
| Library | jmpcct.lib /jmpcct_x64.lib |
| DLL | jmpcct.dll /jmpcct_x64.dll |


I'm being lazy right now so I won't write much in this template. Just consider it as a first sketch that will be completed later.
Also, You can add a css file which name is the same as your html profile page ('name'.css). Right now there is no style at all so it'll just look boring...
My interest in programming began a long long time ago in a far away land....


We would be happy to provide some information regardig land use.
Please fill in the following fields below using the information about land you can find
here
.


Jonathan earned his degree in game art from Full Sail University. It was there that he combined his passion for gaming with his artistic abilities.
His software skills include world building in Unreal Engine 4 and Unity, image editing in Photoshop, and other image rendering software such as Maya and Zbrush.


JavaScript
JavaScript is the expansive functional side of web development, a vast programming language that has gone through years of constant development and change. Here are numerous resources I've found across the web. You can go ahead and
filter them by library or framework if you like.
Angular
Visit
Angular is Google's framework for building Single Page Applications. The framework is written in Typescript, a superset of JavaScript. It allows you to build your web apps in reusable components and delivers high performant web
experiences.
jQuery
Visit
jQuery is JavaScript's most famous library. Though it's use has diminished in recent years, it's still holds a lot of utility and is found in many projects. As a web developer, understanding jQuery will still be useful. This is
the official website for the library.
Try jQuery
Visit
Try jQuery is an interactive site that teaches the basics of jQuery, focusing on event management and DOM traversal.
React
Visit
React is one of the fastest growing single page application frameworks. React uses JSX to write reusable components. It manages state, (and can do further with Redux) and helps
you develop complex UIs easily.
React Native
Visit
React Native is a framework that allows you to use React to construct mobile apps on Android and iOS.
Vue.js
Visit
Vue is described by Gregg Pollack of VueMastery.com as "an approachable, versatile and performant JavaScript framework that allows you to make a more maintainable and testable
codebase."
Vue Mastery
Visit
Vue Mastery contains a whole course load of materials that will teach you Vue, which is a small, yet powerful and performant framework for web apps.
Electron
Visit
Electron is a JavaScript framework that allows you to build desk top apps using HTML, CSS and JavaScript. VSCode, Atom, and Github Desktop are a few examples of what Electron can do.
Eloquent JavaScript
Visit
Eloquent JavaScript is an online book that . . . There is also a physical book you can pick up, if you're the type who likes holding paper.
JavaScript 30
Visit
JavaScript 30 is one of Wes Bos's courses. It is a free course that challenges you to 30 minutes of JavaScript coding a day. He provides you with a small project to make and challenges you to make it yourself and then goes over
the solution in clear detail.
JS Tips
Visit
JS Tips is a collection of JavaScript tips that will help you be a better programmer.
Christian Engvall
Visit
Christian Engvall is a software developer. His site has numerous articles about web development
Node.js
Visit
Node.js is a JavaScript runtime that can run on the console or the server. Node.js enables us to use JavaScript to write server-side scripts.
Node School
Visit
Node School is a website with courses that will teach you Node.js.
Coursetro
Visit
Coursetro has numerous courses on JavaScript and various frameworks. It has a mixture of free and premium courses.
Phaser
Visit
Phaser is a JavaScript framework that uses HTML canvas to write games.
egghead
Visit
egghead delivers courses on JavaScript and many of its frameworks and libraries in concise courses that get to the point.
Codeburst
Visit
Codeburst contains a vast number of web development courses ranging from basic JavaScript and jQuery, to frameworks like React and Node.
Lodash
Visit
Lodash is a popular JavaScript utility library, known for its speed and modularity. You can download the entire Lodash library and apply it to your project, or cherry pick specific functions. Lodash also has an fp library
to support functional programming.
Underscore
Visit
Underscore provides a whole mess of utilities for JavaScript programmers. Underscore provides over 100 helper functions without extending built in objects.
Next.js
Visit
Next.js is a small framework for React apps, designed for static and server-side rendered applications. Next.js makes React applications simple.
Job Ready JavaScript
Visit
This is a guide to help any potential web developer to be job ready with his or her JavaScript abilities.
Scotch School
Visit
Scotch is a subscription based site that teaches web development. They focus on building apps and teaching the why behind the code. Their projects will also help you build out your portfolio.


The flexible, dynamic nature of the AWS cloud gives developers and admins the flexibility to launch, configure, use, and terminate processing, storage, networking, and other resources as needed. In any fast-paced agile environment, security guidelines and policies can be overlooked in the race to get a new product to market before the competition.
Imagine that you had the ability to verify that existing and newly launched AWS resources conformed to your organization’s security guidelines and best practices without creating a bureaucracy or spending your time manually inspecting cloud resources.
AWS Config is a service that enables you to assess, audit, and evaluate the configurations of your AWS resources. Config continuously monitors and records your AWS resource configurations and allows you to automate the evaluation of recorded configurations against desired configurations. With Config, you can review changes in configurations and relationships between AWS resources, dive into detailed resource configuration histories, and determine your overall compliance against the configurations specified in your internal guidelines. This enables you to simplify compliance auditing, security analysis, change management, and operational troubleshooting.
AWS Config is designed to help you assess compliance with your internal policies and regulatory standards by providing you visibility into the configuration of your AWS resources as well as third-party resources, and evaluating resource configuration changes against your desired configurations on a continuous basis.
You can use AWS Config as your framework for creating and deploying governance and compliance rules across your AWS accounts and regions. You can codify your compliance requirements as AWS Config rules and author remediation actions using AWS Systems Manager Automation documents and package them together within a conformance pack that can be easily deployed across an organization. Therefore, using AWS Config, you can automate assessment of your resource configurations and resource changes to help you ensure continuous compliance and self-governance across your AWS infrastructure.


My Work
Bloc Jams
Bloc Jams is a digital music player similar to Spotify that was created by combining jQuery, JavaScript, HTML, and CSS. This web application was then refactored to use Google’s AngularJS framework.
Bloc Chat
Bloc chat is a chat room that allows users to register an account for the site, create chat rooms, and post and send messages.


--- layout: archive title: Zulip Chat Archive permalink: /stream/113489-new-members/topic/definition.20for.20GCD.20for.20ideals.2C.20fractional.20field.html ---
Is the fractional field for an arbitrary integral domain defined anywhere in mathlib?
I see that localization is defined, which I guess would be the way to define a fractional field if it isn't already present.
Also, is the ideal definition of GCD, i.e. gcd(I) = the smallest Principal Ideal containing I
present in Lean?
Thanks! Somehow I missed that one while grepping for quotient :upside_down:
{% endraw %}Last updated: Apr 24 2020 at 19:02 UTC


Photo: Sandy Weston
How is your program going? Are you getting in the miles? Are you cross-training?  And are you stretching?
Right now, there is so much training to fit into your day. I know all of these questions are overwhelming, but remember: “It is all about balance.” Honestly, I think I find “balance” in my life about one day a year, but I refuse to give up trying to achieve it. It's that important to me. It is my mind-set.
As fitness people, we know the importance of being in the right frame of mind. But do we practice it on a daily basis? Do we really believe it works?
Positive affirmations such as “I feel great” really do work. (I know what you are thinking! How corny! My husband even says it's “goofy.”) Without getting too scientific, studies have shown that if you repeat positive sayings, your body will start acting positively as well. In other words, your mind is communicating with your body, and your body starts believing it.
Every morning, my three-year-old son wakes up and says to me, "It's going to be a great day, Mom.” Some mornings, I completely agree with him. Other mornings, I don't, but I try to keep saying it, and — eventually — I get there. Admittedly, on some days it takes longer than on others, but I do get there.
So here's what I want you to do: Try using positive affirmations for a week, and see how you feel. I would prefer if you said it aloud, but it is okay just to think it. Writing them down is also helpful.  On your off-workout day, just say your affirmations whenever you can during the day.
Here are some ideas for affirmations, but feel free to make up your own. Just be consistent. Trust me on this — it works.
When you wake up:
Midday:
Before working out:
After working out:
Before bed:
I know it sounds corny and maybe goofy, but try it. Even if you don't yell it from the rooftops (you don't even have to tell anyone your doing it), I promise you that your workouts, runs, and days will only get better.
High hopes,
Sandy Weston


Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter.Chemistry includes topics such as the properties of individual atoms, how atoms form chemical bonds to create chemical compounds, the interactions of substances through intermolecular forces that give matter its general properties, and the interactions between substances through chemical reactions to form different substances.
Chemistry is sometimes called the central science because it bridges other natural sciences, including physics, geology and biology. For the differences between chemistry and physics see comparison of chemistry and physics.
(Source: Wikipedia: Chemistry)Inorganic chemistry deals with the synthesis and behavior of inorganic and organometallic compounds. This field covers all chemical compounds except the myriad organic compounds (carbon based compounds, usually containing C-H bonds), which are the subjects of organic chemistry. The distinction between the two disciplines is far from absolute, as there is much overlap in the subdiscipline of organometallic chemistry. It has applications in every aspect of the chemical industry, including catalysis, materials science, pigments, surfactants, coatings, medications, fuels, and agriculture.
(Source: Wikipedia: Inorganic Chemistry)Organic chemistry is the study of the structure, properties, composition, reactions, and preparation of carbon-containing compounds, which include not only hydrocarbons but also compounds with any number of other elements, including hydrogen (most compounds contain at least one carbon–hydrogen bond), nitrogen, oxygen, halogens, phosphorus, silicon, and sulfur. This branch of chemistry was originally limited to compounds produced by living organisms but has been broadened to include human-made substances such as plastics. The range of application of organic compounds is enormous and also includes, but is not limited to, pharmaceuticals, petrochemicals, food, explosives, paints, and cosmetics.
(Source: American Chemical Society: Organic Chemistry)Physical chemistry is the study of macroscopic, atomic, subatomic, and particulate phenomena in chemical systems in terms of the principles, practices and concepts of physics such as motion, energy, force, time, thermodynamics, quantum chemistry, statistical mechanics, analytical dynamics and chemical equilibrium. (From the author: never learn Physical Chem)
Analytical chemistry is the science of obtaining, processing, and communicating information about the composition and structure of matter. In other words, it is the art and science of determining what matter is and how much of it exists. In 2012 (salary survey data), analytical chemistry was the most popular field of work for ACS chemists. (From the author: easier to find job than front end?)
(Source: Wikipedia: Inorganic Chemistry)My first project is about to use π-π interaction to enhance the binding for cation.
This idea challenges the long-standing idea of preorganization (see this for more information), so it met some difficulty upon publication.


We proudly announce General Availability of Ballerina 0.970.0. Download now! Ballerina 0.970.0 is an exciting new release of the programming language.
The 0.970.0 release represents significant changes from the 0.964.0 release and is not backwards compatible. This release represents the changes after a series of design reviews that had material impact on the language design, syntax, and toolchain. The changes are so significant that to those with previous exposure, Ballerina will appear as an entirely new language.
With these changes, the release notes cover the features of the language from a design point of view, and we are forgoing the traditional approach of release notes covering the incremental changes from release to release. We hope to hit 1.0 milestone before the end of 2018 and will guarantee backwards compatibility at that stage.
Key highlights of Ballerina capabilities included into this release are:
Concurrent: Worker support for defining parallel execution units with fork/join semantics, and asynchronous function invocations, which contains improved BVM scheduler functionality.
Transactional: First class support for transaction semantics, including distributed transactions.
Textual and graphical syntaxes: Sequence diagrams focused on showing worker and endpoint interactions. Endpoints represent network services. Each worker is sequential code, that can zoom in graphically yet represents really textual code. The design is meant to make it easier to understand complex distributed interactions
Integration specialization: Brings fundamental concepts, ideas, and tools of distributed system integration into the programming language and offers a type safe, concurrent environment to implement such applications. These include distributed transactions, reliable messaging, stream processing, workflows, and container management platforms.
Learn more about the Ballerina philosophy.
Ballerina programs operate on a universe of values, and each value belongs to only one basic type such as int
, boolean
, map
, record
, function
, etc. There are three kinds of values corresponding to three kinds of basic types. They are simple values (e.g., int
, string
, boolean
), structured values (e.g., record
, map
, array
), and behavioral values (e.g., function
, object
).
The types int
, float
, string
, boolean
, blob
, and nil
are called simple basic types because they are basic types with only simple values. Simple values are always immutable.
nil
type has only one value that is denoted by ()
. boolean
type has only two values named true
and false
. The implicit initial value of a variable of type boolean
is false
.int
type denotes the set of 64-bit signed integers. The implicit initial value of a variable of type int
is 0
.float
type denotes double precision IEEE 754 floating point numbers. The implicit initial value of a variable of type float
is +0.0
.string
type denotes the set of sequences of unicode code points. The implicit initial value of a variable of type string
is the empty sequence.blob
type denotes the set of sequences of 8-bit bytes. The implicit initial value of a variable of type blob
is the empty sequence. Structured basic values create structures from other values. A structured value belongs to exactly one of the following basic types:
tuple
is an immutable list of two or more values of fixed length. 0
.map
type defines a mutable mapping from keys that are strings to values of the same type.table
type is a data structure that organizes information in rows and columns. Can be used to create an in-memory table using a type constraint, insert data to it and then access/delete the data.xml
type represents a sequence of zero or more XML items. Each item can be an element, a text, a comment, or a processing instruction.The following are Ballerina’s basic behavioural values.
function
with zero or more specified input parameter types and a single return type.future
value represents a value to be returned by an asynchronous function invocation. object
is a collection of public/private typed fields along with attached functions that allows you to create new, user-defined data types with behavior. The implicit initial value would be an object
where each field has the implicit initial value for its type.stream
type represents a stream of events, which allows publishing events to the stream and subscribing to receive events from the stream. union
types are types whose set of values is the union of the value spaces of its component types. For example, you can use a variable of a union type to store a string
or an int
, but there is only one value at any given time. Syntactically, you can define a union type with component types separated by “|” (vertical bar). T
optionally, for any T. You can syntactically represent this as T?
or T|()
.any
data type is the root of the Ballerina data types. It can represent a variable of any data type. When you do not have prior knowledge of the data type of your variable, you can assign any
as the type. Values of these variables can come from dynamic content such as the request and response messages and the user input. The any
type allows you to skip compile-time data type checks.string
, number
, true
, false
, null
), an array of values, or an object. Ballerina has a single type named json
that can represent any JSON value. Thus, json
is a built-in union type in Ballerina, which can contain values of type string
, float
, boolean
, an array of any
, or a map of any
.Field access is the syntax of accessing child elements inside structural typed values, such as objects, records, JSON, XML, etc. Fields can be accessed using two operators:
Dot operator - Name of the field precedes by a dot, e.g., foo.bar
Index operator - Name of the field comes within two brackets. Name can be any string
value expression, e.g., foo[bar]
Both of these operators perform the nil-lifting by default. That is, it allows to walk down the child fields, without worrying whether there will be null along the way. In an event of null, it will stop the navigation and the value of the entire expression will be null.
Array elements can be accessed by the index using the index operator. The index always has to be an integer valued expression. Similar to accessing fields, accessing arrays also performs the nil-lifting default, e.g., foo[index], foo[2].
Match expression is a way of checking the type of an expression and executing some other expression based on the type of the first expression. It is a form of a type switch. Match expression contains patterns inside, with a type associated to it. Type of each pattern should be matched to at-least one of the types of the expression that is being tested.
Elvis operator is a conditional operator that can be used to handle null
values. It evaluates an expression and if the value is null
, executes the second expression. The elvis operator takes two operands and uses the ‘?:’ symbol to form it.
An if/else
statement provides a way to perform conditional execution. It contains three sections: an if
block, followed by multiple else if
blocks, and finally a single else
block. All the else if
blocks and the else
blocks are optional. Any number of statements can be defined inside each of these blocks.
A match
statement is a type switching construct that allows selective code execution based on the type of the expression that is being tested. The match
statement can have one or more patterns with a type associated to it. Each pattern have statements that will get executed if that type is matched.
The while
looping construct will iterate and execute the code block within the while block continuously, until the condition for while loop is true
.
The foreach
looping construct will traverse through the items of a collection of data such as arrays, maps, JSON, and XML and execute the given code block.
With the above two looping constructs, statements such as break
and next
can also be used, where the break
statement would end the loop and next
statement would go to the next iteration in the loop.
Iterable operations can be used with types such as array
, map
, json
, table
, and xml
. Currently available iterable operations are map
, filter
, count
, average
and foreach
. The map
is a transform operation that can transform the given source element to a target element. The filter
operation can filter the given element for the given condition. The count
, average
and foreach
are terminal type of operations that will terminate and either give a result out or will consume the elements and terminate the iteration.
A Ballerina transaction is a series of data manipulation statements that must either fully complete or fully fail, and thereby leave the system in a consistent state. Ballerina supports following three types of transactions over databases and message brokers.
The transaction block is used handle Ballerina transactions. Any transaction aware operations performed within the transaction block are automatically committed or rolled back at the end of the block. Within transaction block, abort
or retry
statements can be used to explicitly force to abort the transaction or retry the transaction.
Typically, errors indicate erroneous conditions in the program. The Ballerina approach is to introduce a first-class error concept that can both be returned as yet another return value (and thereby processed by the caller as it deems fit) or be thrown.
In the case of an error situation where the caller can recover from it, this error must be returned from the function, rather than throwing the error. Generally, errors will only be thrown, in the case where the caller cannot recover from the error, hence, the program will not be able to continue.
The try-catch-finally
blocks are basically used for catching and handling exceptions thrown during execution. The try block contains the operations you need to execute. The catch block is used to handle the exceptions that are thrown by the operations in the try block. You can define many catch blocks to catch the different error types that are thrown. The finally block is always executed even if errors are thrown or not. Therefore, you can add all the crucial operations to the finally block.
The error lifting operator allows to walk down a set of fields of an object or tuple, without worrying whether there will be a error or null along the way. In an event of error/null, it will stop the navigation and the value of the entire expression will be error/null.
check
is a unary expression that is used to handle errors. The check
expression removes the error
type from the result of the sub expression and handle error case separately. If check
is used within a function
, having error
as the return
type or one of the return types, then upon an error, it causes to immediately return from the enclosing function with that error. Otherwise, error will be thrown. With this behavior, check expression can also be considered as a built-in match.
The concurrency model is based on workers, which are the fundamental execution units defined in Ballerina. The worker model is designed to be very light-weight constructs, which follows a fully non-blocking approach in its executions, which in-turn makes sure it has optimal utilization of the CPU.
In Ballerina, every callable unit, that is, a function, action or a resource is made up of one or more workers. A worker is a concurrent execution unit, which is independently run when a function call is made. If the user does not define an explicit worker, a default implicit worker is automatically defined, and the function contents are added to it.
Any function or action can be invoked in an asynchronous mode by prefixing the call with the start
keyword. The return value of this expression will always be a future
object. The future object can be constrained to a specific type, to be equal to the result type that the function is returning. If not, for void functions, it will be unconstrained. The returned future object can be used to extract the result by blocking until the function call is done, check the current status of the asynchronous call, or cancel the running execution.
The fork/join construct in Ballerina is used in order to split (fork
) the current function execution to multiple workers, do some processing in parallel, and join
together the results of the workers to a single execution again.
Ballerina locks are used for concurrency management, encapsulating a block of statements will acquire the locks for each global or service level variable reference used within those block of statements.
Ballerina functions operate the same way as any other language. It is a mechanism to create a reusable unit of functionality within a program. Ballerina functions can have three types of parameters.
A function pointer is a Ballerina type that allows you to use functions as variables, arguments to functions, and function return values. The name of a function serves as a pointer to that function when called from other functions or operations. The definition of the function name provides the type of the pointer in terms of a function signature.
Lambdas are a syntactic shortcut for defining inline functions. In comparison to a normal function definition, the only missing part is the name.
Ballerina’s underlying language semantics were designed by modeling how independent parties communicate via structured interactions. Subsequently, every Ballerina program can be displayed as a sequence diagram of its flow with endpoints, including synchronous and asynchronous calls. Ballerina’s syntax has both textual and graphical representation designed around sequence diagrams,therefore, the way a developer thinks when writing Ballerina code encourages strong interaction best practices.
Ballerina’s textual syntax is largely inspired by C, Java, and Go languages. The key language constructs in Ballerina are as follows.
Function:
import ballerina/io;
function add(int a, int b) returns (int) {
return a + b;
}
function main(string... args) {
int result = add(5, 6);
io:println(result);
}
Worker:
import ballerina/io;
function main(string... args) {
worker w1 {
io:println("Hello, World! #w1");
} worker w2 {
io:println("Hello, World! #w2");
} worker w3 {
io:println("Hello, World! #w3");
}
}
Service:
import ballerina/http;
service<http:Service> hello bind { port: 9090 } {
sayHello(endpoint caller, http:Request req) {
http:Response res = new;
res.setPayload("Hello, World!");
var result = caller->respond(res);
}
}
Ballerina’s graphical syntax resembles a sequence diagram. The control flow within a worker is represented with flow diagram based elements. Graphical representation of a service is represented with network interactions.
Ballerina platform comes with the Composer IDE, which allows you to edit and view Ballerina programs graphically and textually. VS Code plugin can be also used to view Ballerina programs graphically.
Ballerina has first class support for services and endpoints. HTTP/HTTP2, WebSockets, WebSub, gRPC, and JMS are some of the available service types. These services are exposed via listener endpoints, which can be secured and monitored. Client endpoints connect to different types of external endpoints and they are inherently resilient. Additionally, commonly used integration message formats, such as XML and JSON, are built-in to the type system of the language. In the context of integration specialization, the following are the released features.
Dispatching to service based on service version by introducing service config annotation to declare versioning rules.
ballerina
@http:ServiceConfig {
basePath:"/hello/{version}",
versioning:{
pattern:"v{Major}.{Minor}",
allowNoVersion:true,
matchMajorVersion:true
}
}
Primitive type support for the Path parameter. The primitive types are string
, int
, float
, and boolean
.
```ballerina
@http:ResourceConfig {
path:”/product/{id}/{name}/{price}”
}
productInfo(endpoint caller, http:Request req, int id, string name, float price) { // some code } ```
Connection throttling support for client endpoint.
ballerina
endpoint http:Client clientEP {
url: "some url",
connectionThrottling: {
maxActiveConnections: 5,
waitTime: 30000
}
};
Introduce setPayload()
to the HTTP request and response to take any type of payload. The any
type can be string
, xml
, json
, blob
, io:ByteChannel
, or mime:Entity[]
.
WebSocket client/server endpoint supports the following features.
Read/write support for Text, Binary, Ping/Pong, and Close WebSocket frames. The following is a sample code for handling WebSockets Text and Binary frames.
```ballerina
service
onBinary(endpoint ep, blob data, boolean finalFrame) { ep->pushBinary(data, final = finalFrame) but { error e => log:printError(“Error”, err=e) }; } } ```
WebSockets secure connections support (WSS://
).
Circuit breaker support for the HTTP client endpoint to gracefully handle network failures. Following is a sample of CircuitBreaker configuration.
ballerina
endpoint http:Client cbClientEP {
url: "http://localhost:8080",
// Circuit breaker options
circuitBreaker: {
rollingWindow: {
timeWindowMillis: 10000,
bucketSizeMillis: 2000
},
failureThreshold: 0.2,
resetTimeMillis: 10000,
statusCodes: [400, 404, 500]
},
timeoutMillis: 2000
};
Failover support for HTTP client endpoint.
ballerina
endpoint http:LoadBalanceClient lbBackendEP {
// Define the set of HTTP clients that need to be load balanced.
targets: [
{ url: "http://localhost:8080/mock1" },
{ url: "http://localhost:8080/mock2" },
{ url: "http://localhost:8080/mock3" }
],
// The algorithm used for load balancing.
algorithm: http:ROUND_ROBIN,
timeoutMillis: 5000
};
Ballerina provides built-in implementation of the MIME specification. Following are some of the features. Support discrete media types. Support composite media types. * multipart/form-data. * multipart/mixed. * multipart/alternative. * multipart/relative. Ability to recognize and separate parts of unrecognized subtypes of multipart entities. Encapsulate multiple body parts in a single message. * Decode multipart messages.
Allow introducing WebSub Hubs, Subscribers and Publishers and support WebSub features including subscription and unsubscription, honouring lease seconds values and authenticated content distribution.
Ballerina’s WebSub implementation supports JSON content and provides the following functionalities.
onIntentVerification
accepting intent verification requests and onNotification
accepting content delivery requests. This includes following features.onIntentVerification
resource is not specified. import ballerina/log;
import ballerina/websub;
endpoint websub:Listener websubEP {
port: 8181
};
@websub:SubscriberServiceConfig {
path: "/websub",
subscribeOnStartUp: true,
topic: "<TOPIC_URL>",
hub: "<HUB_URL>",
leaseSeconds: 3600,
secret: "<SECRET>"
}
service websubSubscriber bind websubEP {
onNotification(websub:Notification notification) {
log:printInfo("WebSub Notification Received: " + notification.payload.toString());
}
}
Ballerina WebSub Hub: A Hub service which accepts subscription requests from subscribers, and delivers content to the subscribers on notification from publishers. This includes following features.
Ballerina WebSub Publisher: Publishers can bring up their own Ballerina Hub, to which they will publish updates, and allow subscribers to subscribe for their topics.
gRPC is a protocol which is layered over HTTP/2 and enables client and server communication by combination of any supported languages. In gRPC a client application can directly call methods on a server application on a different machine, making it easier for you to create distributed applications and services.
Ballerina also supports creating gRPC client and server as other supported language. Ballerina based gRPC server/client supports interacting with server and client written either in Ballerina or any other supported languages. For example: you can easily create gRPC server in Ballerina and connect with client in Go. Syntax for writing simple gRPC unary server is like below,
endpoint grpc:Listener listener {
port:9090,
};
service SamplegRPCService bind listener {
receiveMessage (endpoint caller, string name) {
// service resource logic goes here.
error? err = caller->send(<response message>);
_ = caller->complete();
}
}
Ballerina follows code first approach to create gRPC service which means you write Ballerina gRPC service like above and Ballerina compiler will generate service contract file(.proto file) automatically. From the service contract, you can either generate client code in Ballerina and from any other supported languages. In Ballerina, the client code are generated using the built-in proto compiler.
The main features of Ballerina gRPC are, - Ballerina gRPC service supports all RPC types. - Unary - Server streaming - Client streaming - Bidirectional Streaming - Ballerina gRPC service supports communicating with client written from any supported language. - Supports passing/retrieving headers. - Supports generating client code using the built-in proto compiler. - Supports error handling. - Supports secured communication with client and server.
Ballerina Database client endpoints allow you to connect to SQL-based relational database systems and perform data definition, data access, and data manipulation operations on the database. The following database client endpoints are supported: - JDBC - For any JDBC supported database. - MySQL - For MySQL database - H2 - For H2 database
The following features are supported in all the data clients.
- Data manipulation/definition support via update
, call
, updateWithGeneratedKeys
operations.
- Batch data update support via batchUpdate
operation.
- Data access support via select
operation, which allows easy access of data using returned tables.
- Proxy table support, which allows read/delete on the actual DB table via a proxied table.
- All operations are transaction aware.
endpoint jdbc:Client testDB {
url: "jdbc:mysql://localhost:3306/testdb",
username: "root",
password: "root",
poolOptions: { maximumPoolSize: 5 },
dbOptions: { useSSL: false }
};
table<Student> tb = check testDB->select("SELECT * FROM student", Student);
Messaging connectors enable the services and programs written in Ballerina to communicate with messaging backends like Ballerina Message Broker and ActiveMQ. The messaging connector API provides features like transactions, message headers, properties, and different acknowledgement mode support to address the common requirements of a modern integration engineer when integrating with a messaging system.
The Ballerina JMS API provides the constructs to connect to any JMS provider as shown below.
endpoint jms:SimpleQueueReceiver consumer {
initialContextFactory: "bmbInitialContextFactory",
providerUrl: "amqp://admin:admin@ballerina/default?brokerlist='tcp://localhost:5672'",
queueName: "MyQueue"
};
service<jms:Consumer> jmsListener bind consumer {
onMessage(endpoint consumer, jms:Message message) {
// Application logic
}
}
The Ballerina MB API provides the constructs to connect to the Ballerina Message Broker provided in the Ballerina platform, as shown below.
endpoint mb:SimpleQueueReceiver receiver {
host: "localhost",
port: 5672,
queueName: "MyQueue"
};
service<mb:Consumer> mbListener bind receiver {
onMessage(endpoint consumer, mb:Message message) {
// Application logic
}
}
The Ballerina standard library provides a set of commonly used functionalities. The following packages are available as a part of the standard library:
Provides an interface for looking up user data for authentication and authorization purposes. Also it contains a sample implementation that uses a Ballerina configuration file as user registry.
// Check if the user exists (for authentication)
auth:ConfigAuthProvider authProvider;
boolean isAuthenticated = authProvider.authenticate(<username>, <password>);
// Retrieve the scopes of the user (for authorization)
string[] scopes = authProvider.getScopes(<username>);
Provides a configurable in-memory caching solution that supports both time-based eviction and size-based eviction.
Provides a configuration lookup and resolve mechanism, with the option for securing configurations, and an API for reading these configurations.
// Look up a string config value
string host = config:getAsString(“http.host”);
// Look up an int config value. If the specified key cannot be
// found, the default value is returned
int port = config:getAsInt(“http.port”, default = 9090);
Provides a set of functions for some of the commonly used hashing algorithms.
Provides a directory listener that can be used to listen to directory events.
import ballerina/file;
import ballerina/log;
endpoint file:Listener localFolder {
path:"/home/ballerina/Input",
recursive:false
};
service watcher bind localFolder {
onCreate (file:FileEvent m) {
string msg = "Create: " + m.name;
log:printInfo(msg);
}
onDelete (file:FileEvent m) {
string msg = "Delete: " + m.name;
log:printInfo(msg);
}
onModify (file:FileEvent m) {
string msg = "Modify: " + m.name;
log:printInfo(msg);
}
}
Provides an asynchronous I/O framework to source/sink that reads/writes as bytes, characters, and records.
// Retrieving a ByteChannel to the file.
io:ByteChannel channel = io:openFile(filePath, permission);
// Reading the bytes from the channel
var result = channel.read(numberOfBytes)
// Writing some bytes to the channel.
var result = channel.write(content, startOffset);
// Reading/writing characters of different encodings e.g.: utf-8
// First, get the ByteChannel representation of the file.
io:ByteChannel channel = io:openFile(filePath, permission);
io:CharacterChannel characterChannel = new(channel, encoding);
// Read content as characters
var content = characterChannel.read(numberOfChars);
// Write characters
channel.write(content, startOffset);
// Reading a JSON
match characterChannel.readJson(){
json result =>{
return result;
}
error err =>{
//handle error
}
}
// Writing a JSON
match characterChannel.writeJson(content){
//handle match conditions
}
// Reading and writing delimited text records
io:ByteChannel channel = io:openFile(filePath, permission);
// Create a `character channel` from the `byte channel` to read content as text.
io:CharacterChannel characterChannel = new(channel, encoding);
// Convert the `character channel` to a `record channel`
//to read the content as records.
io:DelimitedTextRecordChannel delimitedRecordChannel = new(characterChannel, rs=rs, fs=fs);
//Read Text Record
var recordResp = delimitedRecordChannel.getNext();
//Write string [] as records
delimitedRecordChannel.write(records);
io:CSVChannel srcCsvChannel = io:openCsvFile("./filepath");
match channel.getNext() {
string[] fields => {
// Process fields
}
// Handle error and the rest
}
// Write an string [] as CSV
dstChannel.write(records);
Provides an API for logging.
Provides the common types and constants used across all the database client endpoints.
Provides a set of functions for performing commonly used mathematical calculations and operations.
Provides utility functions for reading annotations and deep equality checks.
Provides utility functions and records related to the runtime.
Provides a set of functions for retrieving details related to the system.
Provides an API for managing task timers and task appointments.
Provides a set of functions for handling, parsing and formatting date and time.
Ballerina Language Server provides the code intelligence for Ballerina programming. Ballerina Language Server can be integrated with any Language Server Protocol (LSP) supported development tool to provide consistent code intelligence throughout. Ballerina Language Server comes with the following set of features.
Identifies and highlights both semantic and syntactic errors.
Code completion triggers while editing text, and a user can also explicitly trigger completions for a given context.
When hovering over an item, an overview of that item appears. For example, if the item is a function, hover support provides an overview of the function signature.
Signature Help provides a compressed set of function signature information. Signature Help triggers when you type “(“ or “,”. Currently supports only the functions, and on the trigger, user will be shown the function parameters and types, along with the parameter descriptions.
Goto Definition will be used in order to jump to the definition of a certain item. Goto Definition can be triggered based on the development tool’s defined trigger options.
Finds all the references of a defined item. This supports finding item references in the same file and also references in other packages in the same project.
Code Action prompts the user with a defined set of actions available for a given language construct and also for certain diagnostic types. Code Actions include the following: - Add imports - Add missing imports.
Supports adding documentation for a single top-level item or all the top-level constructs in a file.
The Ballerina VSCode plugin includes the following features: - Syntax highlighting - Intellisense for Ballerina language via Ballerina Language Server - Diagramming (view Ballerina programs graphically) - Debugging
The Ballerina IDEA plugin includes the following features: - Syntax highlighting - Code completion and suggestions - Code formatting - Go to definitions - Find usages - Code diagnostics - Ballerina program running and debugging
Composer is an IDE included with the Ballerina platform that allows you to design and write Ballerina programs textually as well as graphically. It also comes with a set of features targeted for integration development. - Graphical interaction flow designing - Textual editing support for Ballerina - Intelligent code completion via Ballerina Language Server - Run and Debug support for Ballerina programs - Design-first API development with Open API Specification - Try-it client - Dev time service tracing
The Ballerina API Gateway allows users to expose services in a managed manner. The built-in API endpoint in Ballerina supports securing the exposed services. The main features of the API endpoint are: - Basic authentication - JWT-based authentication - Configuration-file-based authentication provider to store usernames, passwords, scopes, and their associations - Authorization using scopes - Specifying authentication and authorization rules at service or resource levels - Inheriting authentication/authorization rules from service level and overriding at the resource level - Authentication and authorization at downstream services via JWT token propagation
Sample service secured with basic authentication:
import ballerina/http;
// The endpoint used here is 'http:SecureListener', which by default tries to
// authenticate and authorize each request. The developer has the option to
// override the authentication and authorization at service and resource level.
endpoint http:SecureListener ep {
port: 9090
};
@http:ServiceConfig {
basePath: "/hello",
authConfig: {
authentication: { enabled: true },
scopes: ["scope1"]
}
}
// Auth configuration comprises of two parts - authentication & authorization.
// Authentication can be enabled by setting 'authentication:{enabled:true}'
// annotation attribute.
// Authorization is based on scopes, where a scope maps to one or more groups.
// For a user to access a resource, the user should be in the same groups as
// the scope.
// To specify one or more scope of a resource, the annotation attribute
// 'scopes' can be used.
service<http:Service> echo bind ep {
@http:ResourceConfig {
methods: ["GET"],
path: "/sayHello",
authConfig: {
scopes: ["scope2"]
}
}
// The authentication and authorization settings can be overridden at
// resource level.
// The hello resource would inherit the authentication:{enabled:true} flag
// from the service level, and override scope defined in service level
// (scope1) with scope2.
hello(endpoint caller, http:Request req) {
http:Response res = new;
res.setPayload("Hello, World!!!");
_ = caller->respond(res);
}
}
Ballerina Message Broker (BMB) is a lightweight, easy to use message broker designed for use with microservices for their messaging requirements. The main features of BMB are: - AMQP 0-9-1 transport with TLS support - Active-Passive HA support - CLI tool to manage the broker - RDBMS-based message persistence - Admin REST API - Messaging metrics for monitoring MB - Message tracing - Local and distributed transaction support - JMS support - Cloud native config support - Authentication and authorization extensions - In-memory mode
Monitoring, tracing, and logging are three ways of observing a system. Ballerina programs have default instrumentation for metrics monitoring and distributed tracing with OpenTracing compliance. Ballerina metrics monitoring is powered by Prometheus, and it should be configured externally to scrape metrics data from the Ballerina metrics endpoint that is started with each Ballerina VM. Ballerina’s default distributed tracing is powered by Jaeger. Ballerina logs can be read and fed to any external log monitoring system like Elastic Stack to perform log monitoring and analysis.
Ballerina observability enables developers to understand the execution and performance impact introduced by the Ballerina program. For example, by enabling the metrics monitoring and distributed tracing, developers can identify slow services and can drill down from the services to the actual request hop that is causing the delay in the overall request flow. Similarly, by log monitoring and analysis, the additional debug information regarding any unfavorable situations can be revealed to pinpoint the root cause.
Developers can enable a Ballerina program to collect the data to observe by simply using the --observe
flag (with default configurations) or passing specific Ballerina configurations when running the Ballerina program. The external systems, such as Prometheus and Jaeger, need to be used to analyze and graphically represent the collected data from a Ballerina program.
Ballerina builder extensions run after the compilation phase. These extensions analyze code to generate deployment artifacts and provide utilities to make deployment of your apps and services easier.
When a developer starts building a project, the system starts by parsing the source code, which is followed by dependency analysis, compilation, and a phase at which deployment artifact generation can take place.
These deployment artifacts can be in the form of simple files or complex types like container images, virtual images, etc. The Ballerina builder extension supports the following deployment artifacts: - Dockerfiles - Docker images - Kubernetes artifacts
It is possible for third parties and the ecosystem to create their own annotations and builder extensions that generate different kinds of deployment artifacts. You can publish these extensions on Ballerina Central for others to use.
The ballerina
command is a tool for compiling, running, and building Ballerina programs. It also comes with a set of utilities to manage Ballerina packages and projects.
The ballerina run
command compiles and runs Ballerina program source files, binaries, or packages. If a Ballerina source file (.bal
file) or a source package is given, the run command compiles and runs it. The compilation is done internally and does not generate a binary file.
You may use the Ballerina build
command to compile a source and provide the generated binary file (.balx
file) to the run
command. The binary runs much faster than a source file, because the source file run requires a compilation phase.
You must have either a main()
function or services or both in order to run a program or a package. When both the main()
function and services are present, run
executes services first and then executes the main()
function.
The ballerina init
command creates a Ballerina project and some sample source files to get you started. It can additionally create packages and the ballerina.toml
file when run in interactive mode using -i
flag. The ballerina.toml
file is used to specify the organization name and version of the project, which is mandatory when pushing to Ballerina Central.
The ballerina build
command compiles Ballerina sources and writes the output to a file. By default, the output filename for a package is the package name suffixed with .balx
. The default output for a source will have the .bal
suffix replaced with .balx
. If the output file is specified with the -o
flag, the output will be written to the given output file name.
The ballerina push
command uploads the given package to the Ballerina Central repository. You will be redirected to create an account during the first attempt.
When you push a package to Ballerina Central, it will validate the organization for the user against the org-name defined in your package’s ballerina.toml
file. Therefore, you must pick the organization name that you intend to push the package into and set that as the org-name in the package ballerina.toml
file.
You may also push packages to your home repository if you want to share a package between two projects in the same dev machine using ballerina push --repository home
. ballerina install
is an alias for the same.
The ballerina pull
command downloads a package from Ballerina Central to your home repository cache. This same behavior happens when you build a project with a package import. The pull
command will download it beforehand, so it will be available for build even when offline.
The ballerina list
command lists dependencies of a program source or package in a tree format.
The ballerina search
command searches Ballerina Central for the given text appearing in the organization name, package name, or package descriptions.
The ballerina test
command allows you to compile and run Ballerina test sources and prints a summary of the test results. You can execute tests in a single test file, a test package, or an entire Ballerina project. Use ballerina test
without any parameters to execute tests for the entire project. Use ballerina test <packagename>
to execute tests within the specified package. Use ballerina test <balfile>
to execute the given Ballerina test file. Note that imports from other packages will not work for file executions. File path can be a relative or absolute.
The ballerina doc
command generates API documentation for a given program or package. If no source or package name is given, it will generate API documentation for all the packages in the current project folder. The default output location of API docs is a folder named api-docs
.
The ballerina swagger
command provides the following Swagger utilities:
- The Swagger to Ballerina utility will generate Ballerina source code for a provided Swagger/OAS3 definition. Ballerina supports two types of code generation. mock
generation will generate a mock Ballerina service. client
generation will generate a Ballerina client stub.
- The Ballerina to Swagger utility can be used to export an OAS3 definition of a Ballerina service.
Build time client stub generation is also possible with the @swagger:ClientEndpoint
and @swagger:ClientConfig
annotations.
The gRPC protobuf tool is used to generate the sample client and client stub using the service protobuf definition via the 3.4.0 protoc compiler.
The ballerina encrypt
command encrypts values containing sensitive information such as passwords and secrets. These encrypted values can be used by placing them in a configuration file or by passing them as runtime arguments, which can then be read through the Config API. It will automatically decrypt the encrypted configuration values on demand.
Ballerina is a compiled language. The Ballerina compiler transforms the source code to Ballerina bytecode, which is the instruction set that the Ballerina bytecode interpreter understands. It is also the intermediate representation to which a source program is transformed by the Ballerina compiler.
The Ballerina Virtual Machine (BVM) is a software process that executes Ballerina programs. BVM is a combination of all of the following components: - Instruction set (Ballerina bytecode). - Bytecode interpreter: a virtual CPU that performs the instruction cycle fetch-decode-execute. - Storage for instructions and operands. - Function call stack. - Instruction pointer, which points to the next instruction to be executed.
The BVM architecture and instruction set are designed based on register-based virtual machine architecture.
The bytecode interpreter in BVM is responsible for executing instructions. Instruction is an encoded behavior. It contains an opcode and one or more operands. Here is a sample instruction:
iadd 0 1 2 - Add integers in 0th and 1st registers and store the result in the 2nd register.
One of the core functionality of the Ballerina VM is the worker scheduler. This is used to schedule all the workers that are executed in the system. During a function invocation, all the workers that belong to the functions are scheduled to be executed in the BVM scheduler. The scheduler will check for available resources and will schedule the workers appropriately. Each worker has a life cycle state that it goes through, which represents being ready, running, waiting for response, waiting on locks, and finally the finished state. The worker scheduling follows a fully non-blocking mode, where the execution threads of the workers will never block for I/O, locks, sleep, etc. Instead, the execution thread will always be freed up for CPU usages for other workers. In this manner, Ballerina ensures the most efficient usage of CPU resources.
map
/record
/json
are not the same yeterror
type has does not have a isError property of the singleton type
:
record { true isError; string message; error? cause; }check
is an expression whereas in the spec it is defined as a statement.match
statement and but
expressiontable
values only support key constraintspackage
whereas the spec uses the terms component
and module
identifier
lexer rules are not tight as the rules defined by the specificationblob
literals are not supported new
expressions are not supported for records and streamsvar
declarations are not allowed at the package level match
statement expects the patterns to be exhaustiverecord
destructuring assignment is not availableYou can download the Ballerina distributions, try samples, and read the documentation at https://ballerina.io. You can also visit the Quick Tour to get started. We encourage you to report issues, improvements, and suggestions at the Ballerina Github Repository.


validation_fixer module¶
-
class
validation_fixer.
CoreFixer
[source]¶ Bases:
validation_fixer.Utilities
,validation_fixer.Display
,validation_fixer.UserInput
-
class
validation_fixer.
Utilities
[source]¶ Bases:
object
-
get_components
()[source]¶ Loads the methods for validation calculations from Core, then builds the cross references needed to track relations between equations (e.g. one equation that fails has TOTREV2 in it, so the program finds all equations with TOTREV2 and displays those also)
-


#96
Serious & Unreported Crime at the Casinos (Adapted from a report by Cst. David Au of Richmond CIS)
#90
Incident Report from River Rock on Unusual Financial Transaction (IN20200006443) - January 29, 2020
#89
Not public by order of the Commissioner
#84
Email from Gordon Friesen to Steve Beeksma RE: Under $50K buy ins in $20 bills - September 23, 2011.
#83
Not public by order of the Commissioner
#82
Not public by order of the Commissioner
#81
Not public by order of the Commissioner
#73
Overview Report: Past Reports and Recommendations Related to the Gaming Sector in British Columbia
#58
Briefing Document dated October 16, 2019 - Single Regulator for Real Estate - Rule-making procedures
#41
Draft - Ministry of Attorney General - Anti-Money Laundering Deputy Ministers Terms of Reference
#12
Not public by order of the Commissioner
#11


virsh-domblklist
List information about block devices associated with a virtual machine.
See also: `virsh`.
More information: home page
- List the target name and source path of the block devices:
virsh domblklist --domain vm_name
- List the disk type and device value as well as the target name and source path:
virsh domblklist --domain vm_name --details


Grades
Home
View Teachers
View Classes
View Students
View Grades
Grades:
Student Name:
Class Name:
Grade:
{% for g in grade_result %}
{{ g[0][0][1]}} {{ g[0][0][2]}}
{{ g[2][0][1]}}
{{ g[1][0][1]}}
{% endfor %}


Project Team
A successful project requires many people to play many roles. Some members write code or documentation, while others are valuable as testers, submitting patches and suggestions.
The project team is comprised of Members and Contributors. Members have direct access to the source of a project and actively evolve the code-base. Contributors improve the project through submission of patches and suggestions to the Members. The number of Contributors to the project is unbounded. Get involved today. All contributions to the project are greatly appreciated.
Members
The following is a list of developers with commit privileges that have directly contributed to the project in one way or another.
Contributors
There are no contributors listed for this project. Please check back again later.


Expression object for dense matrix-transpose dense matrix Schur product.The DMatTDMatSchurExpr class represents the compile time expression for Schur product between a row-major dense matrix and a column-major dense matrix.
More...
#include <DMatTDMatSchurExpr.h>
Inherits blaze::SchurExpr< DenseMatrix< DMatTDMatSchurExpr< MT1, MT2 >, false > >, and blaze::Computation.
|
| enum | : bool { returnExpr = !IsTemporary<RN1>::value && !IsTemporary<RN2>::value
} |
| | Compilation switch for the selection of the subscript operator return type. More...
|
| |
| enum | : bool { useAssign = RequiresEvaluation<MT1>::value || RequiresEvaluation<MT2>::value || !returnExpr
} |
| | Compilation switch for the serial evaluation strategy of the Schur product expression. More...
|
| |
|
using | RT1 = ResultType_< MT1 > |
| | Result type of the left-hand side dense matrix expression.
|
| |
|
using | RT2 = ResultType_< MT2 > |
| | Result type of the right-hand side dense matrix expression.
|
| |
|
using | RN1 = ReturnType_< MT1 > |
| | Return type of the left-hand side dense matrix expression.
|
| |
|
using | RN2 = ReturnType_< MT2 > |
| | Return type of the right-hand side dense matrix expression.
|
| |
|
using | CT1 = CompositeType_< MT1 > |
| | Composite type of the left-hand side dense matrix expression.
|
| |
|
using | CT2 = CompositeType_< MT2 > |
| | Composite type of the right-hand side dense matrix expression.
|
| |
|
using | ExprReturnType = MultExprTrait_< RN1, RN2 > |
| | Expression return type for the subscript operator.
|
| |
|
|
LeftOperand | lhs_ |
| | Left-hand side dense matrix of the Schur product expression.
|
| |
|
RightOperand | rhs_ |
| | Right-hand side dense matrix of the Schur product expression.
|
| |
template<typename MT1, typename MT2>
class blaze::DMatTDMatSchurExpr< MT1, MT2 >
Expression object for dense matrix-transpose dense matrix Schur product.
The DMatTDMatSchurExpr class represents the compile time expression for Schur product between a row-major dense matrix and a column-major dense matrix.
◆ anonymous enum
template<typename MT1, typename MT2>
Compilation switch for the selection of the subscript operator return type.
The returnExpr compile time constant expression is a compilation switch for the selection of the ReturnType. If either matrix operand returns a temporary vector or matrix, returnExpr will be set to false and the subscript operator will return it's result by value. Otherwise returnExpr will be set to true and the subscript operator may return it's result as an expression.
◆ anonymous enum
template<typename MT1, typename MT2>
Compilation switch for the serial evaluation strategy of the Schur product expression.
The useAssign compile time constant expression represents a compilation switch for the serial evaluation strategy of the Schur product expression. In case either of the two dense matrix operands requires an intermediate evaluation or the subscript operator can only return by value, useAssign will be set to 1 and the Schur product expression will be evaluated via the assign function family. Otherwise useAssign will be set to 0 and the expression will be evaluated via the function call operator.
◆ DMatTDMatSchurExpr()
template<typename MT1, typename MT2>
Constructor for the DMatTDMatSchurExpr class.
- Parameters
-
| lhs | The left-hand side operand of the Schur product expression. |
| rhs | The right-hand side operand of the Schur product expression. |
◆ at()
template<typename MT1, typename MT2>
Checked access to the matrix elements.
- Parameters
-
| i | Access index for the row. The index has to be in the range . |
| j | Access index for the column. The index has to be in the range . |
- Returns
- The resulting value.
- Exceptions
-
| std::out_of_range | Invalid matrix access index. |
◆ canAlias()
template<typename MT1, typename MT2>
template<typename T >
Returns whether the expression can alias with the given address alias.
- Parameters
-
| alias | The alias to be checked. |
- Returns
- true in case the expression can alias, false otherwise.
◆ canSMPAssign()
template<typename MT1, typename MT2>
Returns whether the expression can be used in SMP assignments.
- Returns
- true in case the expression can be used in SMP assignments, false if not.
◆ columns()
template<typename MT1, typename MT2>
Returns the current number of columns of the matrix.
- Returns
- The number of columns of the matrix.
◆ isAliased()
template<typename MT1, typename MT2>
template<typename T >
Returns whether the expression is aliased with the given address alias.
- Parameters
-
| alias | The alias to be checked. |
- Returns
- true in case an alias effect is detected, false otherwise.
◆ isAligned()
template<typename MT1, typename MT2>
Returns whether the operands of the expression are properly aligned in memory.
- Returns
- true in case the operands are aligned, false if not.
◆ leftOperand()
template<typename MT1, typename MT2>
Returns the left-hand side dense matrix operand.
- Returns
- The left-hand side dense matrix operand.
◆ operator()()
template<typename MT1, typename MT2>
2D-access to the matrix elements.
- Parameters
-
| i | Access index for the row. The index has to be in the range . |
| j | Access index for the column. The index has to be in the range . |
- Returns
- The resulting value.
◆ operator~() [1/2]
template<typename MT, bool SO>
Conversion operator for non-constant matrices.
- Returns
- Reference of the actual type of the matrix.
◆ operator~() [2/2]
template<typename MT, bool SO>
Conversion operator for constant matrices.
- Returns
- Constant reference of the actual type of the matrix.
◆ rightOperand()
template<typename MT1, typename MT2>
Returns the right-hand side transpose dense matrix operand.
- Returns
- The right-hand side transpose dense matrix operand.
◆ rows()
template<typename MT1, typename MT2>
Returns the current number of rows of the matrix.
- Returns
- The number of rows of the matrix.
The documentation for this class was generated from the following file:


Table formatting according to APA
How to format tables in APA Style? Before formatting tables you have created to support the existing data in your article, you should consider checking the following questions to ensure whether embedding tables is necessary or whether it the data could be presented otherwise: Is the table necessary? Is...
[Read More]