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Re: Method Chaining

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From Michael Selik <michael.selik@gmail.com>
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Subject Re: Method Chaining
Date Fri, 17 Jun 2016 13:34:33 +0000
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On Fri, Jun 17, 2016 at 5:31 AM Steven D'Aprano <steve@pearwood.info> wrote:

> (g.move_to((p1 + p2a) / 2)
>   .line_to(p1 + (p2 - p1) * frac)
>   .line_to((p1 + p1a) / 2)
>   .stroke()
>   )
>
> the parens and indentation more clearly mark this chunk of code as a
> unit.


I prefer reserving indentation for where they're required ("for", "while",
"if", etc.). In this case, I'd use an extra blank line before and after.
Or, better, I'd move the chunk of code into a function by itself.

On the other hand, I like the fact that methods which are
> conceptually procedures that operate by side-effect return None.
>

Exactly. The chained version looks like each method is returning a modified
copy. The Pandas library isn't perfect, but it has a good consistency for
methods returning copies unless explicitly "inplace=True", in which case
the method returns None.

Paraphrasing Jakob's law of user experience [0], it doesn't matter if your
design is better. People are more familiar with the design of other
libraries and will expect yours to behave the same way: impure methods
return None, unless named "pop" or a similar standard.

[0] https://www.nngroup.com/articles/end-of-web-design/

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Thread

Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-16 19:02 -0700
  Re: Method Chaining Steven D'Aprano <steve@pearwood.info> - 2016-06-17 12:39 +1000
  Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 04:23 +0000
    Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-16 21:37 -0700
      Re: Method Chaining Ned Batchelder <ned@nedbatchelder.com> - 2016-06-17 01:13 -0700
        Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 01:38 -0700
          Re: Method Chaining Jussi Piitulainen <jussi.piitulainen@helsinki.fi> - 2016-06-17 11:45 +0300
        Re: Method Chaining Steven D'Aprano <steve@pearwood.info> - 2016-06-17 19:28 +1000
          Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 13:34 +0000
            Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 15:26 -0700
              Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 22:45 +0000
              Re: Method Chaining Michael Selik <michael.selik@gmail.com> - 2016-06-17 23:10 +0000
          Re: Method Chaining Rustom Mody <rustompmody@gmail.com> - 2016-06-17 09:48 -0700
            Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 15:25 -0700
            Re: Method Chaining Pete Forman <petef4+usenet@gmail.com> - 2016-06-18 13:04 +0100
              Re: Method Chaining Joonas Liik <liik.joonas@gmail.com> - 2016-06-18 17:05 +0300
                Re: Method Chaining Pete Forman <petef4+usenet@gmail.com> - 2016-06-18 16:42 +0100
              Re: Method Chaining Rustom Mody <rustompmody@gmail.com> - 2016-06-18 08:35 -0700
                Re: Method Chaining Pete Forman <petef4+usenet@gmail.com> - 2016-06-19 11:16 +0100
              Re: Method Chaining Ethan Furman <ethan@stoneleaf.us> - 2016-06-18 13:47 -0700
              Re: Method Chaining Joonas Liik <liik.joonas@gmail.com> - 2016-06-19 14:56 +0300
              Re: Method Chaining Ethan Furman <ethan@stoneleaf.us> - 2016-06-19 08:01 -0700
              Re: Method Chaining Michael Torrie <torriem@gmail.com> - 2016-06-19 09:14 -0600
              Re: Method Chaining Ethan Furman <ethan@stoneleaf.us> - 2016-06-19 08:56 -0700
                Re: Method Chaining Rustom Mody <rustompmody@gmail.com> - 2016-06-19 09:03 -0700
        Re: Method Chaining Lawrence D’Oliveiro <lawrencedo99@gmail.com> - 2016-06-17 15:22 -0700
          Re: Method Chaining Ned Batchelder <ned@nedbatchelder.com> - 2016-06-17 17:02 -0700

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