Programming Idioms

#1

Post by decentralised » Wed, Apr 29, 2020, 7:53 AM UTC

Programming Idioms
programming-idioms.org

Re: Programming Idioms

#2

Post by kashfi » Wed, Apr 29, 2020, 8:45 AM UTC

Thanks for sharing.

Re: Programming Idioms

#3

Post by saagarjha » Wed, Apr 29, 2020, 8:52 AM UTC

These kinds of collections can be nice, but I think it’s fair to warn against looking at them too closely. Sometimes they’re not actually idiomatic and often the implementations have differences in them that see non-obvious.

Re: Programming Idioms

#4

Post by KnobbleMcKnees » Wed, Apr 29, 2020, 8:53 AM UTC

This is really cool and seems pretty up-to-date ... which leaves me surprised that Obj-C is present but Swift isn't. (Even moreso considering that both Java and Kotlin are present).

Re: Programming Idioms

#5

Post by junke » Wed, Apr 29, 2020, 9:10 AM UTC

    Sorry, [Common Lisp] is currently not a supported language.

New time sink avoided.

Re: Programming Idioms

#6

Post by hazbo » Wed, Apr 29, 2020, 9:14 AM UTC

Previous discussion: https://news.ycombinator.com/item?id=21080606

Re: Programming Idioms

#7

Post by LandR » Wed, Apr 29, 2020, 9:17 AM UTC

The clojure one to reverse a string makes it a sequence of characters, then reverses that sequence and puts it back together again as a string..

Why not jsut:

     (require '[clojure.string :as str])
     (let [s "hello"]
         (str/reverse s))
     => "olleh"

Reversing a string is in the core library...

Re: Programming Idioms

#8

Post by tgv » Wed, Apr 29, 2020, 9:22 AM UTC

saagarjha wrote: post #3

These kinds of collections can be nice, but I think it’s fair to warn against looking at them too closely. Sometimes they’re not actually idiomatic and often the implementations have differences in them that see non-obvious.

And some have problems: the Python example of reading a file into a string is:

    lines = open(f).read()

which doesn't close the file. The second C example of this task is tricky, and seems to miss an offset.

The C and Go implementations of uniform random integer include the upper limit, the Python and Rust implementations don't.

And that's just from quickly browsing.

Re: Programming Idioms

#9

Post by natmaka » Wed, Apr 29, 2020, 9:27 AM UTC

Re: Programming Idioms

#10

Post by diggan » Wed, Apr 29, 2020, 9:31 AM UTC

LandR wrote: post #7

The clojure one to reverse a string makes it a sequence of characters, then reverses that sequence and puts it back together again as a string.. Why not jsut: (require '[clojure.string :as str]) (let [s "hello"] (str/reverse s)) => "olleh" Reversing a string is in the core library...

Well, clojure.string/reverse is relying on StringBuilder so I guess you could call it not just Clojure but Clojure + Java really. Source for clojure.string/reverse is this: `(.toString (.reverse (StringBuilder. s))))`

(The implementation of clojure.string/reverse) would only work on Clojure running on JVM. Clojure-clr, ClojureScript or any of the other ones, would use a difference implementation, not using StringBuilder. `(apply str (reverse s))` is then I guess "more" general across Clojure implementations. So Clojure is using StringBuilder, ClojureScript is using regexes + split to list + reverse + rejoin, ClojureCLR I'm not sure, but probably something C# specific.

But in the end, that's all semantics and the point is moot. Since Clojure is a pragmatic language, using an already defined function is obviously better, so no reason why you wouldn't use clojure.string/reverse, all the Clojure implementations have it exposed already.