undefined | Better HN

0 pointsjunke10y ago0 comments

The thread was more about mattlondon's problem with sorting according to the same key in different structs. I used of modified version of this example[0] to illustrate what I think is his problem[1]: you can sort circles and planet by radius, and probably many other things in the original case, but you are required to copy-paste the definitions.

I can understand that instantiating templates by hand is not so bad. But once it is written, maintaining the code is not so obvious for someone not acquainted with it.

Did I introduce a bug or not in the code? Not easy to tell without context.

[0] http://stackoverflow.com/a/28999886/124319

[1] https://play.golang.org/p/Dq0AJjkhhr

0 comments

5 comments · 2 top-level

NateDad10y ago· 2 in thread

It's 3 lines of code the most newbie of newbies could understand... if this is the biggest problem I have in my day to day programming, I'll be happy.

Is it mildly annoying to type out those three lines? Sure. You know what's a lot more annoying? Basically everything else in programming.

junkeOP10y ago

The problem with code duplication is not about being lazy, or having to type. I love typing.

When you dive into a codebase full of vaguely similar yet different blocks, it starts being more than mildly annoying to understand the intent of the code and make the correct change.

NateDad10y ago

nobutseriously...

    type userList []*User
    
    func (u userList) Len() int           { return len(u) }
    func (u userList) Swap(i, j int)      { u[i], u[j] = u[j], u[i] }
    func (u userList) Less(i, j int) bool { return u[i].Name() < u[j].Name() }

What change would you ever need to make to this code that would be at all difficult? The first two methods on userList are never ever ever going to change. The only thing you could possibly want to change is how to sort inside the Less method... and that code would be the exact same code you'd have to change no matter what language you're in. You still have to define the sort one way or another for non-trivial types.

So, yes, it's some extra typing... but saying that it makes maintenance harder is just plain wrong.

1 more reply

jhalderman10y ago· 1 in thread

Why not write an interface for getting the radius and a radius sorter for sorting on that interface? I made a modified version of your code to illustrate.

https://play.golang.org/p/Ya7tUhDnO2

*edited a typo

junkeOP10y ago

Thanks a lot for your example. I would certainly take this approach and I am happy that you took the time to write it.

I feel a little sorry for you because I put a trap for the parent poster in the original code.

I wrote "a[j] < a[i]".

You "fixed" it while refactoring, which would be the good thing to do if I made a typo. If however I really wanted to sort circles differently from planets, then you made an error while refactoring what looked like copy-pasta but wasn't.

My original point was that when you "have" to copy-paste, you cannot clearly see what is or isn't part of the copy and what is new.

You found a way to rewrite the code without much copy- pasting, and I am happy to see that. Still, in other places where code duplication arise, there could be similar problems from a maintenance point of view.

j / k navigate · click thread line to collapse

0 comments

5 comments · 2 top-level

NateDad10y ago· 2 in thread

It's 3 lines of code the most newbie of newbies could understand... if this is the biggest problem I have in my day to day programming, I'll be happy.

Is it mildly annoying to type out those three lines? Sure. You know what's a lot more annoying? Basically everything else in programming.

junkeOP10y ago

The problem with code duplication is not about being lazy, or having to type. I love typing.

When you dive into a codebase full of vaguely similar yet different blocks, it starts being more than mildly annoying to understand the intent of the code and make the correct change.

NateDad10y ago

nobutseriously...

    type userList []*User
    
    func (u userList) Len() int           { return len(u) }
    func (u userList) Swap(i, j int)      { u[i], u[j] = u[j], u[i] }
    func (u userList) Less(i, j int) bool { return u[i].Name() < u[j].Name() }

So, yes, it's some extra typing... but saying that it makes maintenance harder is just plain wrong.

1 more reply

jhalderman10y ago· 1 in thread

Why not write an interface for getting the radius and a radius sorter for sorting on that interface? I made a modified version of your code to illustrate.

https://play.golang.org/p/Ya7tUhDnO2

*edited a typo

junkeOP10y ago

Thanks a lot for your example. I would certainly take this approach and I am happy that you took the time to write it.

I feel a little sorry for you because I put a trap for the parent poster in the original code.

I wrote "a[j] < a[i]".

My original point was that when you "have" to copy-paste, you cannot clearly see what is or isn't part of the copy and what is new.

j / k navigate · click thread line to collapse