CoffeeScript One Liners

http://ricardo.cc/2011/06/02/10-CoffeeScript-One-Liners-to-Impress-Your-Friends.html

by ricardobeat • 15 years ago

108 27 15 years ago

ricardo.cc

Isofarro• 15 years ago

A function walks into a function, turns to one of the members and asks "can I stash my privates in here?"

Argorak5• 15 years ago

Nice collection of examples.

But: I am still struggling with that talk about 'expressiveness' that seems to take hold of every programming piece. To take his first example: To anyone who has an advanced programming vocabulary, his notion of "expressiveness" thing can be reversed. If I read code like this:

    i * 2 for i in [1..10]

I immediately think: "Well, this is a `map`, why doesn't he spell it out?". So my personal "expressive" version is the following:

    [1..10].map (i) -> i*2

In my opinion, it is also clearer, because it can be read from left to right.

I do understand that this might not be the case for other people, but that doesn't make the one option 'more expressive' then the other.

Actually, in the long examples, I find the suffix version extremely odd:

    console.log "Happy Birthday #{if i is 3 then "dear Robert" else "to You"}" for i in [1..4]

I have to read the whole line before I actually find out that this is an iteration. (Besides the fact that putting a conditional into a string interpolation just to make it a oneliner seems a bit odd)

ricardo_• 15 years ago

IMO expressiveness has to do with being close to natural language: "multiply number by 2 for every number in 1 to 10". "map" is CS vocabulary.

The conditional could be placed outside the string and still be a one-liner. It's there mostly for "flow".

adamtulinius• 15 years ago

http://en.wikipedia.org/wiki/Expressive_power

"In computer science, the expressive power of a language describes the ideas expressible in that language."

So, language expressiveness is about what can be expressed in a language, and not really about whether you type "multiply number by 2 for every number in 1 to 10" or use map, since that expresses the same thing.

Argorak5• 15 years ago

We are doing applied CS here, don't we? So lets express us in that language. Also, why do we accept a*2 then? This is short mathematical notation, also a specialized language.

Every field evolves domain languages for a reason: it adds the benefit of naming actions instead of implicitly doing them.

"Being close to natural language" is a red herring. You can try, you will never get there and you will loose any benefit of a domain language.

Also, my point was that interpretations of expressiveness differ vastly, so we should stop claiming that something is more expressive then the other.

thenduks5• 15 years ago

I completely agree. English is English, code is code. I prefer `map`, especially when the function is any more complex than `i * 2`.

And suffix conditionals (and the like) are mostly useful to me when it's much shorter and sweeter, but doesn't lose any clarity:

    return false if somethingBad

endtime2• 15 years ago

>English is English, code is code.

I'm not sure this kind of 'render unto Caesar' thinking is conducive to literate code.

Definitely agree with you on the suffix conditionals.

edanm• 15 years ago

"I do understand that this might not be the case for other people, but that doesn't make the one option 'more expressive' then the other."

Look, I like the comprehensions better. I also think if you polled a large group of programmers and asked them what the code does, more of them will understand the comprehension than the map. Does that mean it's more expressive? I don't know, know one here agrees on a definition for expressiveness. But that's at least one positive (IMO) of comprehensions.

Also, stacking multiple comprehensions together is much easier (cartesian multiple style). E.g.: (i,j) for i in list_1 for j in list_2.

This is much easier to write and understand with comprehensions.

* Note - I know comprehensions from Python, let me know if the cartesian multiple example doesn't work in CoffeeScript.

catshirt• 15 years ago

well, i prefer left to right and "map". clearly it's subjective.

jessedhillon2• 15 years ago

> more of them will understand the comprehension than the map

What? Not if you poll programmers who had to go through SICP or take a real CS curriculum.

btipling• 15 years ago

>" this is only acceptable for application start-up routines"

You gonna come spank me if I do it synchronously and it works for me? I hate when people are so forceful with their opinions.

ricardobeat4• 15 years ago

It's not just an opinion, blocking your event loop will halt the world in nodejs.

Now give me your address, please.

thenduks5• 15 years ago

Yea, he means acceptable from a performance standpoint since in node the event loop will just stop and wait for that to finish before doing anything else. http://nodejs.org/#about

The `*Sync` methods are really only there for convenience sake, so you don't end up with 'banana code' around your whole app because of your initialization (reading config files, etc).

acangiano• 15 years ago

I published a Ruby version here: http://programmingzen.com/2011/06/02/10-ruby-one-liners-to-i...

CoffeeScript One Liners

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