Beginners, These Tricks Will Accelerate Your Coding

When you just start out your programming journey, there are so many shiny tools and technologies to explore, you almost don’t know where to start. Fortunately, there are numerous guides on how to get into different fields such as web development, computer systems, data science, and much more. This article is not one of these guides.

In my spare time, I tutor beginner programmers. When I’m working with them, I notice that even though their programming knowledge is solid, they still suffer from a low-efficiency workflow. I introduced the following tips to my students, and each one immediately benefited from knowing and using them. Often times there was even a reactive “Whoa!” upon learning these tips.

#web-development #programming #computer-science #software-development #productivity

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How to Use Hotwire Rails

Introduction

We are back with another exciting and much-talked-about Rails tutorial on how to use Hotwire with the Rails application. This Hotwire Rails tutorial is an alternate method for building modern web applications that consume a pinch of JavaScript.

Rails 7 Hotwire is the default front-end framework shipped with Rails 7 after it was launched. It is used to represent HTML over the wire in the Rails application. Previously, we used to add a hotwire-rails gem in our gem file and then run rails hotwire: install. However, with the introduction of Rails 7, the gem got deprecated. Now, we use turbo-rails and stimulus rails directly, which work as Hotwire’s SPA-like page accelerator and Hotwire’s modest JavaScript framework.

What is Hotwire?

Hotwire is a package of different frameworks that help to build applications. It simplifies the developer’s work for writing web pages without the need to write JavaScript, and instead sending HTML code over the wire.

Introduction to The Hotwire Framework:

1. Turbo:

It uses simplified techniques to build web applications while decreasing the usage of JavaScript in the application. Turbo offers numerous handling methods for the HTML data sent over the wire and displaying the application’s data without actually loading the entire page. It helps to maintain the simplicity of web applications without destroying the single-page application experience by using the below techniques:

Turbo Frames: Turbo Frames help to load the different sections of our markup without any dependency as it divides the page into different contexts separately called frames and updates these frames individually.
Turbo Drive: Every link doesn’t have to make the entire page reload when clicked. Only the HTML contained within the tag will be displayed.
Turbo Streams: To add real-time features to the application, this technique is used. It helps to bring real-time data to the application using CRUD actions.

2. Stimulus

It represents the JavaScript framework, which is required when JS is a requirement in the application. The interaction with the HTML is possible with the help of a stimulus, as the controllers that help those interactions are written by a stimulus.

3. Strada

Not much information is available about Strada as it has not been officially released yet. However, it works with native applications, and by using HTML bridge attributes, interaction is made possible between web applications and native apps.

Simple diagrammatic representation of Hotwire Stack:

Prerequisites For Hotwire Rails Tutorial

As we are implementing the Ruby on Rails Hotwire tutorial, make sure about the following installations before you can get started.

• Ruby on Rails
• Hotwire gem
• PostgreSQL/SQLite (choose any one database)
• Turbo Rails
• Stimulus.js

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Create a new Rails Project

Find the following commands to create a rails application.

mkdir ~/projects/railshotwire
cd ~/projects/railshotwire
echo "source 'https://rubygems.org'" > Gemfile
echo "gem 'rails', '~> 7.0.0'" >> Gemfile
bundle install  
bundle exec rails new . --force -d=postgresql

Now create some files for the project, up till now no usage of Rails Hotwire can be seen.
Fire the following command in your terminal.

• For creating a default controller for the application

echo "class HomeController < ApplicationController" > app/controllers/home_controller.rb
echo "end" >> app/controllers/home_controller.rb

• For creating another controller for the application

echo "class OtherController < ApplicationController" > app/controllers/other_controller.rb
echo "end" >> app/controllers/home_controller.rb

• For creating routes for the application

echo "Rails.application.routes.draw do" > config/routes.rb
echo '  get "home/index"' >> config/routes.rb
echo '  get "other/index"' >> config/routes.rb
echo '  root to: "home#index"' >> config/routes.rb
echo 'end' >> config/routes.rb

• For creating a default view for the application

mkdir app/views/home
echo '<h1>This is Rails Hotwire homepage</h1>' > app/views/home/index.html.erb
echo '<div><%= link_to "Enter to other page", other_index_path %></div>' >> app/views/home/index.html.erb

• For creating another view for the application

mkdir app/views/other
echo '<h1>This is Another page</h1>' > app/views/other/index.html.erb
echo '<div><%= link_to "Enter to home page", root_path %></div>' >> app/views/other/index.html.erb

• For creating a database and schema.rb file for the application

bin/rails db:create
bin/rails db:migrate

• For checking the application run bin/rails s and open your browser, your running application will have the below view.

Additionally, you can clone the code and browse through the project. Here’s the source code of the repository: Rails 7 Hotwire application

Now, let’s see how Hotwire Rails can work its magic with various Turbo techniques.

Hotwire Rails: Turbo Drive

Go to your localhost:3000 on your web browser and right-click on the Inspect and open a Network tab of the DevTools of the browser.

Now click on go to another page link that appears on the home page to redirect from the home page to another page. In our Network tab, we can see that this action of navigation is achieved via XHR. It appears only the part inside HTML is reloaded, here neither the CSS is reloaded nor the JS is reloaded when the navigation action is performed.

By performing this action we can see that Turbo Drive helps to represent the HTML response without loading the full page and only follows redirect and reindeer HTML responses which helps to make the application faster to access.

Hotwire Rails: Turbo Frame

This technique helps to divide the current page into different sections called frames that can be updated separately independently when new data is added from the server.
Below we discuss the different use cases of Turbo frame like inline edition, sorting, searching, and filtering of data.

Let’s perform some practical actions to see the example of these use cases.

Make changes in the app/controllers/home_controller.rb file

#CODE

class HomeController < ApplicationController
   def turbo_frame_form
   end
   
   def turbo_frame submit
      extracted_anynumber = params[:any][:anynumber]
      render :turbo_frame_form, status: :ok, locals: {anynumber: extracted_anynumber,      comment: 'turbo_frame_submit ok' }
   end
end

Add app/views/home/turbo_frame_form.html.erb file to the application and add this content inside the file.

#CODE

<section>

    <%= turbo_frame_tag 'anyframe' do %>
            
      <div>
          <h2>Frame view</h2>
          <%= form_with scope: :any, url: turbo_frame_submit_path, local: true do |form| %>
              <%= form.label :anynumber, 'Type an integer (odd or even)', 'class' => 'my-0  d-inline'  %>
              <%= form.text_field :anynumber, type: 'number', 'required' => 'true', 'value' => "#{local_assigns[:anynumber] || 0}",  'aria-describedby' => 'anynumber' %>
              <%= form.submit 'Submit this number', 'id' => 'submit-number' %>
          <% end %>
      </div>
      <div>
        <h2>Data of the view</h2>
        <pre style="font-size: .7rem;"><%= JSON.pretty_generate(local_assigns) %></pre> 
      </div>
      
    <% end %>

</section>

Make some adjustments in routes.rb

#CODE

Rails.application.routes.draw do
  get 'home/index'
  get 'other/index'

  get '/home/turbo_frame_form' => 'home#turbo_frame_form', as: 'turbo_frame_form'
  post '/home/turbo_frame_submit' => 'home#turbo_frame_submit', as: 'turbo_frame_submit'


  root to: "home#index"
end

• Next step is to change homepage view in app/views/home/index.html.erb

#CODE

<h1>This is Rails Hotwire home page</h1>
<div><%= link_to "Enter to other page", other_index_path %></div>

<%= turbo_frame_tag 'anyframe' do %>        
  <div>
      <h2>Home view</h2>
      <%= form_with scope: :any, url: turbo_frame_submit_path, local: true do |form| %>
          <%= form.label :anynumber, 'Type an integer (odd or even)', 'class' => 'my-0  d-inline'  %>
          <%= form.text_field :anynumber, type: 'number', 'required' => 'true', 'value' => "#{local_assigns[:anynumber] || 0}",  'aria-describedby' => 'anynumber' %>
          <%= form.submit 'Submit this number', 'id' => 'submit-number' %>
      <% end %>
  <div>
<% end %>

After making all the changes, restart the rails server and refresh the browser, the default view will appear on the browser.

Now in the field enter any digit, after entering the digit click on submit button, and as the submit button is clicked we can see the Turbo Frame in action in the below screen, we can observe that the frame part changed, the first title and first link didn’t move.

Hotwire Rails: Turbo Streams

Turbo Streams deliver page updates over WebSocket, SSE or in response to form submissions by only using HTML and a series of CRUD-like operations, you are free to say that either

• Update the piece of HTML while responding to all the other actions like the post, put, patch, and delete except the GET action.
• Transmit a change to all users, without reloading the browser page.

This transmit can be represented by a simple example.

• Make changes in app/controllers/other_controller.rb file of rails application

#CODE

class OtherController < ApplicationController

  def post_something
    respond_to do |format|
      format.turbo_stream {  }
    end
  end

   end

Add the below line in routes.rb file of the application

#CODE

post '/other/post_something' => 'other#post_something', as: 'post_something'

Superb! Rails will now attempt to locate the app/views/other/post_something.turbo_stream.erb template at any moment the ‘/other/post_something’ endpoint is reached.

For this, we need to add app/views/other/post_something.turbo_stream.erb template in the rails application.

#CODE

<turbo-stream action="append" target="messages">
  <template>
    <div id="message_1">This changes the existing message!</div>
  </template>
</turbo-stream>

This states that the response will try to append the template of the turbo frame with ID “messages”.

Now change the index.html.erb file in app/views/other paths with the below content.

#CODE

<h1>This is Another page</h1>
<div><%= link_to "Enter to home page", root_path %></div>

<div style="margin-top: 3rem;">
  <%= form_with scope: :any, url: post_something_path do |form| %>
      <%= form.submit 'Post any message %>
  <% end %>
  <turbo-frame id="messages">
    <div>An empty message</div>
  </turbo-frame>
</div>

• After making all the changes, restart the rails server and refresh the browser, and go to the other page.

• Once the above screen appears, click on the Post any message button

This action shows that after submitting the response, the Turbo Streams help the developer to append the message, without reloading the page.

Another use case we can test is that rather than appending the message, the developer replaces the message. For that, we need to change the content of app/views/other/post_something.turbo_stream.erb template file and change the value of the action attribute from append to replace and check the changes in the browser.

#CODE

<turbo-stream action="replace" target="messages">
  <template>
    <div id="message_1">This changes the existing message!</div>
  </template>
</turbo-stream>

When we click on Post any message button, the message that appear below that button will get replaced with the message that is mentioned in the app/views/other/post_something.turbo_stream.erb template

Stimulus

There are some cases in an application where JS is needed, therefore to cover those scenarios we require Hotwire JS tool. Hotwire has a JS tool because in some scenarios Turbo-* tools are not sufficient. But as we know that Hotwire is used to reduce the usage of JS in an application, Stimulus considers HTML as the single source of truth. Consider the case where we have to give elements on a page some JavaScript attributes, such as data controller, data-action, and data target. For that, a stimulus controller that can access elements and receive events based on those characteristics will be created.

Make a change in app/views/other/index.html.erb template file in rails application

#CODE

<h1>This is Another page</h1>
<div><%= link_to "Enter to home page", root_path %></div>

<div style="margin-top: 2rem;">
  <%= form_with scope: :any, url: post_something_path do |form| %>
      <%= form.submit 'Post something' %>
  <% end %>
  <turbo-frame id="messages">
    <div>An empty message</div>
  </turbo-frame>
</div>

<div style="margin-top: 2rem;">
  <h2>Stimulus</h2>  
  <div data-controller="hello">
    <input data-hello-target="name" type="text">
    <button data-action="click->hello#greet">
      Greet
    </button>
    <span data-hello-target="output">
    </span>
  </div>
</div>

Make changes in the hello_controller.js in path app/JavaScript/controllers and add a stimulus controller in the file, which helps to bring the HTML into life.

#CODE

import { Controller } from "@hotwired/stimulus"

export default class extends Controller {
  static targets = [ "name", "output" ]

  greet() {
    this.outputTarget.textContent =
      `Hello, ${this.nameTarget.value}!`
  }
}

Go to your browser after making the changes in the code and click on Enter to other page link which will navigate to the localhost:3000/other/index page there you can see the changes implemented by the stimulus controller that is designed to augment your HTML with just enough behavior to make it more responsive.

With just a little bit of work, Turbo and Stimulus together offer a complete answer for applications that are quick and compelling.

Using Rails 7 Hotwire helps to load the pages at a faster speed and allows you to render templates on the server, where you have access to your whole domain model. It is a productive development experience in ROR, without compromising any of the speed or responsiveness associated with SPA.

Conclusion

We hope you were satisfied with our Rails Hotwire tutorial. Write to us at service@bacancy.com for any query that you want to resolve, or if you want us to share a tutorial on your query.

For more such solutions on RoR, check out our Ruby on Rails Tutorials. We will always strive to amaze you and cater to your needs.

Original article source at: https://www.bacancytechnology.com/

#rails #ruby 

Guidelines for Java Code Reviews

Get a jump-start on your next code review session with this list.

Having another pair of eyes scan your code is always useful and helps you spot mistakes before you break production. You need not be an expert to review someone’s code. Some experience with the programming language and a review checklist should help you get started. We’ve put together a list of things you should keep in mind when you’re reviewing Java code. Read on!

1. Follow Java Code Conventions

2. Replace Imperative Code With Lambdas and Streams

3. Beware of the NullPointerException

4. Directly Assigning References From Client Code to a Field

5. Handle Exceptions With Care

…

#java #code quality #java tutorial #code analysis #code reviews #code review tips #code analysis tools #java tutorial for beginners #java code review

HAML Lint: Tool For Writing Clean and Consistent HAML

HAML-Lint

haml-lint is a tool to help keep your HAML files clean and readable. In addition to HAML-specific style and lint checks, it integrates with RuboCop to bring its powerful static analysis tools to your HAML documents.

You can run haml-lint manually from the command line, or integrate it into your SCM hooks.

Requirements

• Ruby 2.4+
• HAML 4.0+

Installation

gem install haml_lint

If you'd rather install haml-lint using bundler, don't require it in your Gemfile:

gem 'haml_lint', require: false

Then you can still use haml-lint from the command line, but its source code won't be auto-loaded inside your application.

Usage

Run haml-lint from the command line by passing in a directory (or multiple directories) to recursively scan:

haml-lint app/views/

You can also specify a list of files explicitly:

haml-lint app/**/*.html.haml

haml-lint will output any problems with your HAML, including the offending filename and line number.

File Encoding

haml-lint assumes all files are encoded in UTF-8.

Command Line Flags

Command Line Flag	Description
--auto-gen-config	Generate a configuration file acting as a TODO list
--auto-gen-exclude-limit	Number of failures to allow in the TODO list before the entire rule is excluded
-c/--config	Specify which configuration file to use
-e/--exclude	Exclude one or more files from being linted
-i/--include-linter	Specify which linters you specifically want to run
-x/--exclude-linter	Specify which linters you don't want to run
-r/--reporter	Specify which reporter you want to use to generate the output
-p/--parallel	Run linters in parallel using available CPUs
--fail-fast	Specify whether to fail after the first file with lint
--fail-level	Specify the minimum severity (warning or error) for which the lint should fail
--[no-]color	Whether to output in color
--[no-]summary	Whether to output a summary in the default reporter
--show-linters	Show all registered linters
--show-reporters	Display available reporters
-h/--help	Show command line flag documentation
-v/--version	Show haml-lint version
-V/--verbose-version	Show haml-lint, haml, and ruby version information

Configuration

haml-lint will automatically recognize and load any file with the name .haml-lint.yml as a configuration file. It loads the configuration based on the directory haml-lint is being run from, ascending until a configuration file is found. Any configuration loaded is automatically merged with the default configuration (see config/default.yml).

Here's an example configuration file:

linters:
  ImplicitDiv:
    enabled: false
    severity: error

  LineLength:
    max: 100

All linters have an enabled option which can be true or false, which controls whether the linter is run, along with linter-specific options. The defaults are defined in config/default.yml.

Linter Options

Option	Description
enabled	If false, this linter will never be run. This takes precedence over any other option.
include	List of files or glob patterns to scope this linter to. This narrows down any files specified via the command line.
exclude	List of files or glob patterns to exclude from this linter. This excludes any files specified via the command line or already filtered via the include option.
severity	The severity of the linter. External tools consuming haml-lint output can use this to determine whether to warn or error based on the lints reported.

Global File Exclusion

The exclude global configuration option allows you to specify a list of files or glob patterns to exclude from all linters. This is useful for ignoring third-party code that you don't maintain or care to lint. You can specify a single string or a list of strings for this option.

Skipping Frontmatter

Some static blog generators such as Jekyll include leading frontmatter to the template for their own tracking purposes. haml-lint allows you to ignore these headers by specifying the skip_frontmatter option in your .haml-lint.yml configuration:

skip_frontmatter: true

Inheriting from Other Configuration Files

The inherits_from global configuration option allows you to specify an inheritance chain for a configuration file. It accepts either a scalar value of a single file name or a vector of multiple files to inherit from. The inherited files are resolved in a first in, first out order and with "last one wins" precedence. For example:

inherits_from:
  - .shared_haml-lint.yml
  - .personal_haml-lint.yml

First, the default configuration is loaded. Then the .shared_haml-lint.yml configuration is loaded, followed by .personal_haml-lint.yml. Each of these overwrite each other in the event of a collision in configuration value. Once the inheritance chain is resolved, the base configuration is loaded and applies its rules to overwrite any in the intermediate configuration.

Lastly, in order to match your RuboCop configuration style, you can also use the inherit_from directive, which is an alias for inherits_from.

Linters

» Linters Documentation

haml-lint is an opinionated tool that helps you enforce a consistent style in your HAML files. As an opinionated tool, we've had to make calls about what we think are the "best" style conventions, even when there are often reasonable arguments for more than one possible style. While all of our choices have a rational basis, we think that the opinions themselves are less important than the fact that haml-lint provides us with an automated and low-cost means of enforcing consistency.

Custom Linters

Add the following to your configuration file:

require:
  - './relative/path/to/my_first_linter.rb'
  - 'absolute/path/to/my_second_linter.rb'

The files that are referenced by this config should have the following structure:

module HamlLint
  # MyFirstLinter is the name of the linter in this example, but it can be anything
  class Linter::MyFirstLinter < Linter
    include LinterRegistry

    def visit_tag
      return unless node.tag_name == 'div'
      record_lint(node, "You're not allowed divs!")
    end
  end
end

For more information on the different types on HAML node, please look through the HAML parser code: https://github.com/haml/haml/blob/master/lib/haml/parser.rb

Keep in mind that by default your linter will be disabled by default. So you will need to enable it in your configuration file to have it run.

Disabling Linters within Source Code

One or more individual linters can be disabled locally in a file by adding a directive comment. These comments look like the following:

-# haml-lint:disable AltText, LineLength
[...]
-# haml-lint:enable AltText, LineLength

You can disable all linters for a section with the following:

-# haml-lint:disable all

Directive Scope

A directive will disable the given linters for the scope of the block. This scope is inherited by child elements and sibling elements that come after the comment. For example:

-# haml-lint:disable AltText
#content
  %img#will-not-show-lint-1{ src: "will-not-show-lint-1.png" }
  -# haml-lint:enable AltText
  %img#will-show-lint-1{ src: "will-show-lint-1.png" }
  .sidebar
    %img#will-show-lint-2{ src: "will-show-lint-2.png" }
%img#will-not-show-lint-2{ src: "will-not-show-lint-2.png" }

The #will-not-show-lint-1 image on line 2 will not raise an AltText lint because of the directive on line 1. Since that directive is at the top level of the tree, it applies everywhere.

However, on line 4, the directive enables the AltText linter for the remainder of the #content element's content. This means that the #will-show-lint-1 image on line 5 will raise an AltText lint because it is a sibling of the enabling directive that appears later in the #content element. Likewise, the #will-show-lint-2 image on line 7 will raise an AltText lint because it is a child of a sibling of the enabling directive.

Lastly, the #will-not-show-lint-2 image on line 8 will not raise an AltText lint because the enabling directive on line 4 exists in a separate element and is not a sibling of the it.

Directive Precedence

If there are multiple directives for the same linter in an element, the last directive wins. For example:

-# haml-lint:enable AltText
%p Hello, world!
-# haml-lint:disable AltText
%img#will-not-show-lint{ src: "will-not-show-lint.png" }

There are two conflicting directives for the AltText linter. The first one enables it, but the second one disables it. Since the disable directive came later, the #will-not-show-lint element will not raise an AltText lint.

You can use this functionality to selectively enable directives within a file by first using the haml-lint:disable all directive to disable all linters in the file, then selectively using haml-lint:enable to enable linters one at a time.

Onboarding Onto a Preexisting Project

Adding a new linter into a project that wasn't previously using one can be a daunting task. To help ease the pain of starting to use Haml-Lint, you can generate a configuration file that will exclude all linters from reporting lint in files that currently have lint. This gives you something similar to a to-do list where the violations that you had when you started using Haml-Lint are listed for you to whittle away, but ensuring that any views you create going forward are properly linted.

To use this functionality, call Haml-Lint like:

haml-lint --auto-gen-config

This will generate a .haml-lint_todo.yml file that contains all existing lint as exclusions. You can then add inherits_from: .haml-lint_todo.yml to your .haml-lint.yml configuration file to ensure these exclusions are used whenever you call haml-lint.

By default, any rules with more than 15 violations will be disabled in the todo-file. You can increase this limit with the auto-gen-exclude-limit option:

haml-lint --auto-gen-config --auto-gen-exclude-limit 100

Editor Integration

Vim

If you use vim, you can have haml-lint automatically run against your HAML files after saving by using the Syntastic plugin. If you already have the plugin, just add let g:syntastic_haml_checkers = ['haml_lint'] to your .vimrc.

Vim 8 / Neovim

If you use vim 8+ or Neovim, you can have haml-lint automatically run against your HAML files as you type by using the Asynchronous Lint Engine (ALE) plugin. ALE will automatically lint your HAML files if it detects haml-lint in your PATH.

Sublime Text 3

If you use SublimeLinter 3 with Sublime Text 3 you can install the SublimeLinter-haml-lint plugin using Package Control.

Atom

If you use atom, you can install the linter-haml plugin.

TextMate 2

If you use TextMate 2, you can install the Haml-Lint.tmbundle bundle.

Visual Studio Code

If you use Visual Studio Code, you can install the Haml Lint extension

Git Integration

If you'd like to integrate haml-lint into your Git workflow, check out our Git hook manager, overcommit.

Rake Integration

To execute haml-lint via a Rake task, make sure you have rake included in your gem path (e.g. via Gemfile) add the following to your Rakefile:

require 'haml_lint/rake_task'

HamlLint::RakeTask.new

By default, when you execute rake haml_lint, the above configuration is equivalent to running haml-lint ., which will lint all .haml files in the current directory and its descendants.

You can customize your task by writing:

require 'haml_lint/rake_task'

HamlLint::RakeTask.new do |t|
  t.config = 'custom/config.yml'
  t.files = ['app/views', 'custom/*.haml']
  t.quiet = true # Don't display output from haml-lint to STDOUT
end

You can also use this custom configuration with a set of files specified via the command line:

# Single quotes prevent shell glob expansion
rake 'haml_lint[app/views, custom/*.haml]'

Files specified in this manner take precedence over the task's files attribute.

Documentation

Code documentation is generated with YARD and hosted by RubyDoc.info.

Contributing

We love getting feedback with or without pull requests. If you do add a new feature, please add tests so that we can avoid breaking it in the future.

Speaking of tests, we use Appraisal to test against both HAML 4 and 5. We use rspec to write our tests. To run the test suite, execute the following from the root directory of the repository:

appraisal bundle install
appraisal bundle exec rspec

Community

All major discussion surrounding HAML-Lint happens on the GitHub issues page.

Changelog

If you're interested in seeing the changes and bug fixes between each version of haml-lint, read the HAML-Lint Changelog.

Author: sds
Source Code: https://github.com/sds/haml-lint
License: MIT license

#haml #lint 

Static Code Analysis: What It Is? How to Use It?

Static code analysis refers to the technique of approximating the runtime behavior of a program. In other words, it is the process of predicting the output of a program without actually executing it.

Lately, however, the term “Static Code Analysis” is more commonly used to refer to one of the applications of this technique rather than the technique itself — program comprehension — understanding the program and detecting issues in it (anything from syntax errors to type mismatches, performance hogs likely bugs, security loopholes, etc.). This is the usage we’d be referring to throughout this post.

“The refinement of techniques for the prompt discovery of error serves as well as any other as a hallmark of what we mean by science.”

• J. Robert Oppenheimer

Outline

We cover a lot of ground in this post. The aim is to build an understanding of static code analysis and to equip you with the basic theory, and the right tools so that you can write analyzers on your own.

We start our journey with laying down the essential parts of the pipeline which a compiler follows to understand what a piece of code does. We learn where to tap points in this pipeline to plug in our analyzers and extract meaningful information. In the latter half, we get our feet wet, and write four such static analyzers, completely from scratch, in Python.

Note that although the ideas here are discussed in light of Python, static code analyzers across all programming languages are carved out along similar lines. We chose Python because of the availability of an easy to use ast module, and wide adoption of the language itself.

How does it all work?

Before a computer can finally “understand” and execute a piece of code, it goes through a series of complicated transformations:

As you can see in the diagram (go ahead, zoom it!), the static analyzers feed on the output of these stages. To be able to better understand the static analysis techniques, let’s look at each of these steps in some more detail:

Scanning

The first thing that a compiler does when trying to understand a piece of code is to break it down into smaller chunks, also known as tokens. Tokens are akin to what words are in a language.

A token might consist of either a single character, like (, or literals (like integers, strings, e.g., 7, Bob, etc.), or reserved keywords of that language (e.g, def in Python). Characters which do not contribute towards the semantics of a program, like trailing whitespace, comments, etc. are often discarded by the scanner.

Python provides the tokenize module in its standard library to let you play around with tokens:

Python

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import io

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import tokenize

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code = b"color = input('Enter your favourite color: ')"

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for token in tokenize.tokenize(io.BytesIO(code).readline):

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    print(token)

Python

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TokenInfo(type=62 (ENCODING),  string='utf-8')

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TokenInfo(type=1  (NAME),      string='color')

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TokenInfo(type=54 (OP),        string='=')

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TokenInfo(type=1  (NAME),      string='input')

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TokenInfo(type=54 (OP),        string='(')

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TokenInfo(type=3  (STRING),    string="'Enter your favourite color: '")

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TokenInfo(type=54 (OP),        string=')')

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TokenInfo(type=4  (NEWLINE),   string='')

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TokenInfo(type=0  (ENDMARKER), string='')

(Note that for the sake of readability, I’ve omitted a few columns from the result above — metadata like starting index, ending index, a copy of the line on which a token occurs, etc.)

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Minimum Java Knowledge Requirements for Your First Coding Job

What does a potential Java junior need to know to get their first job or even qualify for a trainee position in a good company? What tools will help a Java programmer reach the next level? Which technologies should you study, and which ones are better to hold off on?

There is no standard answer to these questions, just as there is no single action plan that would suit absolutely everyone. Some companies are striving for development, constantly introducing new technologies and testing the capabilities of new versions of the language, while others stubbornly cling to old ones. There are also middle options, and perhaps these are most of them.

I get asked this question so often that I decided to write an article that I can then refer to in order to answer it. In addition, it will be useful not only to those who ask me personally but also to everyone who has already decided (or did not decide in any way) to connect their lives with Java programming.

#java #java-development-resources #java-development #learn-to-code #learning-to-code #beginners #tutorial-for-beginners #beginners-to-coding