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Are the codes written/read left to right ?! (a misconception among beginners)

Hooman Talakian on January 15, 2022

Before we begin, we would like to mention that if you are a professional programmer, this article will most probably be a repeat for you, But if yo...
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jzombie profile image
jzombie •

When you write asynchronous code, you can write in any direction:

For example, bottom up:

let message = ''

await Promise.all([
  new Promise(resolve => setTimeout(() => {message += 'world'; resolve()}, 200)),
  new Promise(resolve => setTimeout(() => {message += 'hello '; resolve()}, 100))
])

console.log(message) // Hello world
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hoomantalakian profile image
Hooman Talakian •

exactly. that is what I'm talking about .as I mentioned in the article :
" Note that this code only makes sense for this example, and based on your programming language and work environment, you should make your own interpretation of this example "
It's all about "thinking" about your code and the order depends on your environment. are we in the same page?

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jzombie profile image
jzombie •

Yep, absolutely.

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johnbabu021 profile image
john •

Great

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eljayadobe profile image
Eljay-Adobe •

Let's say you want to get the user's name, capitalize it (which may be incorrect... sorry k d lang), convert it to a greeting, and print it out.

Most languages would do it this way, in pseudo-code:

string name = input();
name = capitalize(name);
string greeting = greet(name);
println(greeting);
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And could do it as a one liner, also in pseudo-code:

println(greet(capitalize(input())));
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See the onion-like nesting? Just like what the article is talking about. This code is read inside-out to see the order of operations.

There are other programming languages that would do the one-liner in a slightly different way, in pseudo-code:

input() | capitalize | greet | println
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No onion! It reads in order, more like the first step-by-step example.

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hoomantalakian profile image
Hooman Talakian • • Edited

I'm not sure if I understand your point, but in every instance you have listed (aside from code direction or difference in programming languages), the syntax would follow the raw data. Am I right? I mean you have a Raw data in the first place and after that you decide how to manage it (based on specific syntax of your program).

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eljayadobe profile image
Eljay-Adobe •

My point is only that there are programming languages which do have the codes such that they are read from left to right, like the ML family of languages.

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hoomantalakian profile image
Hooman Talakian •

Yes, there are many syntactic differences between programming languages, but in this case we are just discussing the path of thought. Thank you for your attention

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Damian Demasi • • Edited

const result = await name.save()

I would read this code as follows: “create a constant variable named result and store in it the result/response of awaiting for the name to be saved”.

But even better, I think is best to read it as we read mathematical equations: from outside to inside.

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hoomantalakian profile image
Hooman Talakian •

Of course, this code can be read, just as you said. This is exactly what "different thinking" is all about. We have just mentioned "one" way of thinking.
By the way, I appreciate your point of view about the mathematical approach.

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hoomantalakian profile image
Hooman Talakian •

Thank you for mentioning. Exactly. "Top to bottom" is the same.