Difference Between Programming Languages
Eden Alvardo
Recently a team of Rust developers have started working on the Rust specification. This RFC 3355 introduced the proposal. My question is that basically what's the difference between a spec and a reference for a programming language? Rust currently has a reference. I know this reference is currently incomplete, but what's the purpose of writing an specification when the reference can be completed? I mean, is there any fundamental difference between specification and reference?
A reference is generally an informal document. It tries its best to show all the parts of a compiler/language, and all behaviours from these parts. However, if something in the compiler doesn't agree with the reference, the compiler is (nix bugs) usually considered correct. The reference is updated to meet the behaviour of the compiler.
A specification is an exact description of a language. This generally includes specifying every rule a hypothetical compiler would have to follow in order to be "compliant", from parsing to runtime behaviour. If the specification and compiler disagree, (nix bugs in the specification, which can happen), the compiler is incorrect. The compiler is updated to comply with the specification.
In languages with multiple compilers, each compiler may have its own reference, but each compiler may comply to the same standard. An excellent example of this is SML, which has compilers such as SML/NJ, MLTon, MoscowML, and many more - each of these have their own reference, but each follows the SML specification. In situations such as this, certain compilers may implement extensions on top of the specification - these would obviously be in the reference, but not the specification.
Why have both? Specifications are often written in highly rarefied, technical language that is of use to people implementing language compilers or interpreters. References, on the other hand, attempt to distill the specification into more digestible information for users of the language. There will only ever be ONE specification from the designer(s) of the language (albeit, possibly with different versions), but there may be zero or more references, depending on how many authors want to take a hand at trying to explain the specification for more ordinary audiences.
For example, take a look at this section from the ECMAScript specification (that defines the JavaScript language). It specifies how the Date constructor should operate. It's incredibly detailed with specific implementation requirements:
I hope you can see why a Reference may try to distill this down to something a developer can use to quickly look up the syntax and high-level details about how to use the Date Constructor. For example, see this reference page from the Mozilla Developer Network:
Keep in mind that the complexity and/or completeness is not the crucial difference between a specification and a reference. I've worked with some specifications that were so simple and clear that I never needed to look for a reference. And I've worked with some references that were so poorly written that I ended up looking at the specification in order to get some clarity. So complexity is not the main difference. The main difference is the prescriptive vs. descriptive purpose of the documents.
Things like the Rust Reference, the Unsafe Code Guidelines Project,the Rustonomicon, and so on, all exist to fulfill certain needs.....Unfortunately, their use is currently limited, because none of these are complete, entirely accurate, or normative.
The emphasis on "normative" was added by me to highlight that the raison d'tre for a specification is to be prescriptive. That's what "normative" means. The "normative vs. informative" dichotomy is just another way of expressing the "prescriptive vs. descriptive" dichotomy. See this article that uses one set of words to explain the other: Standards New Zealand article.
A specification is an exact, unambiguous, and fully complete description of a language's syntax and behavior; a reference is more of an overview of the language, written more informally. It's like the difference between a blueprint of a house and a book describing the house. In the case of Rust, as the RPC describes, there are multiple documents which attempt to be a blueprint; they are suggesting consolidating them into one location. The Rust Reference (from my brief glance over it) seems to already be close in structure to a specification; it's just incomplete.
Programming is a skill that is becoming increasingly sought after in the job market. Having at least a basic understanding of how software functions is helpful for anyone who interacts with technology. With a background in programming, you can get a job coding, designing software, data architecture, or creating intuitive user interfaces.
But what programming language should you learn? You'll find a seemingly infinite number of programming languages that are free to learn and develop projects with online. With the field of technology growing exponentially each year, the internet is a great place to start when trying to explore the latest developments or discover a new skill.
Whichever language you learn, you may find it helpful to take notes or draw diagrams detailing the steps you're taking and why. It's important for programmers to be able to communicate their process to non-technical stakeholders, but taking notes can also be a great learning tool. "Turns out this often comes in handy not only for the sake of creating documentation, but often helps in solving a single task or issue where the underlying tech is challenging to understand," offers Eric Hartzog, a software engineer at Meta. You can learn software engineering from Meta staff by enrolling in one of their online courses or certificate programs, for example, the Meta Front-End Developer Professional Certificate, which focuses on JavaScript, HTML, and CSS.
A procedural language follows a sequence of statements or commands in order to achieve a desired output. Each series of steps is called a procedure, and a program written in one of these languages will have one or more procedures within it. Common examples of procedural languages include:
C++ is a great programming language to learn if you're also interested in learning more about how computers function. While it may not be as readable as other high-level programming languages like Python, it can still be beginner-friendly. You can give it a try for free by enrolling in Codio's introductory online program, Programming in C++: A Hands-on Introduction Specialization. After a month, you'll have created and ran your first program in C++.
This type of language treats a program as a group of objects composed of data and program elements, known as attributes and methods. Objects can be reused within a program or in other programs. This makes it a popular language type for complex programs, as code is easier to reuse and scale. Some common object-oriented languages include:
Linux operating system is the primary choice for those who prefer open-source software [1]. Familiarizing yourself with Linux can be useful for someone who is interested in learning scripting languages.
Instead of telling a computer what to do, a logic programming language expresses a series of facts and rules to instruct the computer on how to make decisions. Some examples of logic languages include:
Back-end languages deal with storage and manipulation of the server side of software. This is the part of the software that the user does not directly come into contact with but supports their experience behind the scenes. This includes data architecture, scripting, and communication between applications and underlying databases.
The biggest factor that differentiates high- and low-level programming languages is whether the language is meant to be easily understood by a human programmer or a computer. Low-level languages are machine-friendly, which makes them highly efficient in terms of memory usage but difficult to understand without the help of an assembler. Since they're not very people-friendly because they don't use human language, they're also not widely used to code. Examples of these machine languages include machine code, binary code, and assembly languages.
High-level languages, on the other hand, are less memory efficient but much more human-friendly. This programming style makes it easier to write, understand, maintain, and debug. Most popular programming languages in use today are considered high-level languages.
The distinction between interpreted and compiled languages has to do with how they convert high-level code and make it readable by a computer. With interpreted languages, code goes through a program called an interpreter, which reads and executes the code line by line. This tends to make these languages more flexible and platform independent.
Compiled languages go through a build step where the entire program is converted into machine code. This makes it faster to execute, but it also means that you have to compile or "build" the program again anytime you need to make a change.
Often, markup languages such as Hypertext Markup Language (HTML) are classified as programming languages. Technically, markup languages are not considered to be the same as programming languages. Instead, they are text-encoding systems made up of symbols that control the formatting and structure of content on a page or document.
Learning to program is easier now than ever. Start writing programs in Python with Python for Everybody from the University of Michigan, learn the basics of web development with HTML, CSS, and JavaScript for Web Developers from Johns Hopkins University, or prepare for a career in IT with Google IT Automation with Python.
A programming language issues a series of commands that help computers, mobile phones, tablets, and other electronic devices function as intended and perform various tasks. There are many types of programming languages, and the correct one must be chosen based on the philosophy and objectives of a particular device or program. In this article, we will explore a range of programming languages and the features that distinguish them from one another. We will also examine the importance of programming languages in the field of integration.
d3342ee215