Tag Archives: ECMAScript

Let’s Talk About JavaScript (Part 1)

Mammon slept. And the beast reborn spread over the earth and its numbers grew legion. And they proclaimed the times and sacrificed crops unto the fire, with the cunning of foxes. And they built a new world in their own image as promised by the sacred words, and spoke of the beast with their children. Mammon awoke, and lo! it was naught but a follower.

from The Book of Mozilla, 11:9 (10th Edition)

To me, the programming languages can mean many things, they are tools to do specific jobs, they are the grammar and words to explain the problem and how to handle the problems, they are the methodologies to understand and explain the world’s reality to logic and entities.

So, to me, the programming language has 3 parts:

1. Methodology: This part is the fundamental side of the language, the philosophy of the language, the core concept of the language. This part explains why this language exists, what’s the original purpose of this language and how it evolved. This is the metaphysics side of the language, but the most important part to understand the language deeply(at least for my opinion).
2. Words and Grammar: This part is the body of the whole language, how to claim a flow, how to claim a data structure.
3. Fundamental Libraries: Although the first 2 part define what the language is, this part(the fundamental libraries) for the language runtime, is very crucial for the language, it even can affect the success of the language

As this article is the first part of the discussion for JavaScript, so, I’ll talk about the methodology of JavaScript first.

As I said, the methodology of the language is more important part for the language, and how the language is designed, why this language should been created should be discuss at the very begining.

First, the name, JavaScript is a trademark of Oracle Corporation(cited as Wikipedia). It is the common name for ECMAScript v3(for today’s talking), so, when I talking about JavaScript in my blog, I was really talking about ECMAScript (and v3 only), just the standard features and standard build in function and objects.

So, what’s an ECMAScript then?

ECMAScript is an object-oriented programming language for performing computations and manipulating computational objects within a host environment.

And what’s the purpose of the ECMAScript, why we should need it?

ECMAScript was originally designed to be a Web scripting language, providing a mechanism to enliven Web pages in browsers and to perform server computation as part of a Web-based client-server architecture.

As we can see in the ECMAScript’s introduction[http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdf] and about [http://inventors.about.com/od/jstartinventions/a/JavaScript.htm]. JavaScript was originally inspirited by the idea of Java, that you can run computation and show animations in the web browser(web pages are really dull back to that year).

So, in the design of JavaScript, the author even don’t think the most fundamental part of the programming language, the Standard Input and Standard Output should be necessary.

As stated in the ECMAScript’s standard:

ECMAScript as defined here is not intended to be computationally self-sufficient; indeed, there are no provisions in this specification for input of external data or output of computed results. Instead, it is expected that the computational environment of an ECMAScript program will provide not only the objects and other facilities described in this specification but also certain environment-specific host objects, whose description and behavior are beyond the scope of this specification except to indicate that they may provide certain properties that can be accessed and certain functions that can be called from an ECMAScript program.

So, we can have a conclusion here:

JavaScript (the language standard ECMAScript v3) is a web scripting language, it is interpreted by the host environment (run time), and besides the language grammar, other things that needed is provided by the host environment, and these things are depended by the host environment, not the language itself.

Then we can get the real fact of JavaScript, it is a interpreting embed language for running the computation tasks by the host environment.

And why I think JavaScript is a good(in fact very good) interpreting embed language, let’s see JavaScript’s philosophy(I try to make it clear, but I’m not teaching JavaScript here, if you want to know the details of JavaScript programming, you can find it on W3CSchool).

1. JavaScript is a Object oriented language

Everything in JavaScript is an object, the object itself is something like a hash table(so javascript don’t need bother to have the data structure for hash tables). Object can have a function as its constructor, and if you are clever enough, you can make objects has parent object (even parent constructor). Because object are somewhat hash table, you can’t have really private in the object, everything you have in the object can be see by anything that can get hold of the object, and JavaScript even let you to iterate the property names in the object.

Since everything is an object, the primitives and functions are object too, but the primitives(numbers for example) can’t really perform as a hash table, though you can setting properties to them, they won’t save any of the property at all.

This purity offers JavaScript the simplicity, if you don’t agree, see what a mess Java has become.

2. JavaScript is a prototype based language

JavaScript is not the first one prototype based language, but I think it is the most famous one. The prototype based nature of javascript can be more easily implemented, and still have the good ways of object oriented. I’ll talk about prototype based language in other articles, so I’ll skip this part in this one.

3. JavaScript is a weak typed language

JavaScript do have types, it has Undefined, Null, Boolean, String, Number and Object type, they can convert to each other (except object, because we don’t have to, everything is an object, remember?)

But the variable don’t have types, so that, you can set anything to any variable and JavaScript won’t complain anything.

But JavaScript won’t let you to create your type, and there is nothing can help you to create a thing like type(since JavaScript is prototype based), it seems weird though(especially from java’s world), but it is really easy for JavaScript’s implementations (If we have Classes, then we must need packages and other many more things, if you don’t want have a mess environment).

4. JavaScript is an embed language

JavaScript can do anything the host environment want it do. So, if the host environment don’t provide the fundamental part JavaScript wants, suppose a calculator can run JavaScript, maybe javascript is just an object oriented calculation language on that calculator, it just can calculate the numbers and output the texts.

All the nature for JavaScripts only points to one conclusion:

JavaScript is build to be an embed language, and it focus on the simplicity of the language(and the implementation of the language), so that, the language(or the implementation) can be run at most machines, and can be easily implemented and mantained.

And as the simplicity of JavaScript (language design), for many circumstances, JavaScript can be the fastest scripting language on any platform, and the philosophy of JavaScript makes it a very nice embed language to use.

Yes, JavaScript have its flaws, but not on its philosophy, we’ll talk that later.

So, a final word for the conclusion of this article:

JavaScript an Objected Oriented Prototype Based Weak Type Scripting Language, its aim is to be a scripting language of simplicity to run in the host environment, and it has achieve its design goal.

We’ll talk about JavaScript’s grammar in next article.