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Re: 3 Suggestions to Make Python Easier For Children

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On Tue, Aug 5, 2014 at 10:31 PM, Skip Montanaro <skip@pobox.com> wrote:
> JavaScript objects have that feature. I find it mildly confusing
> because whenever I see it I have to pause to consider whether the name
> I am looking at is an attribute or a key. This little JS code I just
> typed at my console prompt was also mildly surprising:
>
>> var x = {};
> undefined
>> x.valueOf(47)
> Object {}
>> x["valueOf"] = 12
> 12
>> x.valueOf
> 12
>> x.valueOf(47)
> TypeError: number is not a function

This is partly a consequence of prototype-based inheritance; x.valueOf
will shadow Object.valueOf. Pike allows a similar "dot or square
brackets" notation, but at the expense of not having any methods on
the mapping type itself:

Pike v8.0 release 3 running Hilfe v3.5 (Incremental Pike Frontend)
> mapping a=([]);
> a.foo="bar";
(1) Result: "bar"
> a.foo;
(2) Result: "bar"
> a;
(3) Result: ([ /* 1 element */
              "foo": "bar"
            ])

Since mappings (broadly equivalent to Python dicts) can't have
methods, anything that Python does as a method, Pike has to do as a
stand-alone function. (Swings and roundabouts, though, as those
functions tend to also accept other types, so they're more akin to
Python's len() than dict.pop().) Every design decision has a cost. The
convenience of short-handing mapping lookup is pretty handy
(especially when you're digging into deeply-nested mappings - imagine
parsing an XML or JSON message and then reaching into it for one
specific thing), but it means there are functions rather than methods
for working with them. Take your pick.

ChrisA

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Thread

3 Suggestions to Make Python Easier For Children Mark Summerfield <list@qtrac.plus.com> - 2014-08-01 23:45 -0700
  Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 10:14 +0300
    Re: 3 Suggestions to Make Python Easier For Children Mark Summerfield <list@qtrac.plus.com> - 2014-08-02 00:38 -0700
      Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 11:03 +0300
        Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-03 02:00 +1000
          Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 20:07 +0300
            Re: 3 Suggestions to Make Python Easier For Children Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 18:29 +0100
              Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-02 21:33 +0300
    Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-03 01:43 +1000
      Correct type for a simple “bag of attributes” namespace object (was: 3 Suggestions to Make Python Easier For Children) Ben Finney <ben+python@benfinney.id.au> - 2014-08-03 05:58 +1000
        Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Mark Summerfield <list@qtrac.plus.com> - 2014-08-02 13:46 -0700
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Chris Angelico <rosuav@gmail.com> - 2014-08-03 07:05 +1000
          Re: Correct type for a simple "bag of attributes" namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 22:16 +0100
          Re: Correct type for a simple "bag of attributes" namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-03 07:24 +1000
          Re: Correct type for a simple "bag of attributes" namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 22:23 +0100
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Devin Jeanpierre <jeanpierreda@gmail.com> - 2014-08-02 16:18 -0700
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Chris Angelico <rosuav@gmail.com> - 2014-08-03 09:27 +1000
          Re: Correct type for a simple "bag of attributes" namespace object (was: 3 Suggestions to Make Python Easier For Children) Ian Kelly <ian.g.kelly@gmail.com> - 2014-08-02 18:59 -0600
          Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-02 22:40 -0400
          Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-02 22:43 -0400
          Re: Correct type for a simple "bag of attributes" namespace object Albert-Jan Roskam <fomcl@yahoo.com> - 2014-08-03 02:17 -0700
          Re: Correct type for a simple "bag of attributes" namespace object Peter Otten <__peter__@web.de> - 2014-08-03 11:37 +0200
          Re: Correct type for a simple "bag of attributes" namespace object Albert-Jan Roskam <fomcl@yahoo.com> - 2014-08-03 03:51 -0700
          Re: Correct type for a simple "bag of attributes" namespace object Albert-Jan Roskam <fomcl@yahoo.com> - 2014-08-03 04:14 -0700
          Re: Correct type for a simple "bag of attributes" namespace object Peter Otten <__peter__@web.de> - 2014-08-03 13:23 +0200
            Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-03 17:51 +0300
              Re: Correct type for a simple "bag of attributes" namespace object Roy Smith <roy@panix.com> - 2014-08-03 11:09 -0400
                Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-03 18:52 +0300
              Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-03 18:55 -0400
                Re: Correct type for a simple "bag of attributes" namespace object Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-04 11:19 +1000
                Re: Correct type for a simple "bag of attributes" namespace object Terry Reedy <tjreedy@udel.edu> - 2014-08-04 01:26 -0400
              Re: Correct type for a simple "bag of attributes" namespace object Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-04 10:13 +1000
                Re: Correct type for a simple "bag of attributes" namespace object Roy Smith <roy@panix.com> - 2014-08-03 20:59 -0400
                Re: Correct type for a simple "bag of attributes" namespace object Gregory Ewing <greg.ewing@canterbury.ac.nz> - 2014-08-04 13:00 +1200
                Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-04 08:41 +0300
                Re: Correct type for a simple "bag of attributes" namespace object Ian Kelly <ian.g.kelly@gmail.com> - 2014-08-04 00:41 -0600
                Re: Correct type for a simple "bag of attributes" namespace object Marko Rauhamaa <marko@pacujo.net> - 2014-08-04 09:57 +0300
          Re: Correct type for a simple "bag of attributes" namespace object Akira Li <4kir4.1i@gmail.com> - 2014-08-03 18:22 +0400
      Re: Correct type for a simple “bag of attributes” namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-03 13:28 +0100
        Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 08:40 -0400
          Re: Correct type for a simple “bag of attributes” namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-03 22:56 +1000
            Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 09:25 -0400
              Re: Correct type for a simple “bag of attributes” namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-03 23:35 +1000
                Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 10:36 -0400
                Re: Correct type for a simple “bag of attributes” namespace object Chris Angelico <rosuav@gmail.com> - 2014-08-04 01:00 +1000
      Re: Correct type for a simple “bag of attributes” namespace object Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-03 18:38 +0100
        Re: Correct type for a simple “bag of attributes” namespace object Roy Smith <roy@panix.com> - 2014-08-03 13:44 -0400
  Re: 3 Suggestions to Make Python Easier For Children Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-02 08:46 +0100
    Re: 3 Suggestions to Make Python Easier For Children Mark Summerfield <list@qtrac.plus.com> - 2014-08-02 01:03 -0700
      Re: 3 Suggestions to Make Python Easier For Children Terry Reedy <tjreedy@udel.edu> - 2014-08-02 19:14 -0400
  Re: 3 Suggestions to Make Python Easier For Children Terry Reedy <tjreedy@udel.edu> - 2014-08-02 19:12 -0400
  Re: 3 Suggestions to Make Python Easier For Children Brian Blais <bblais@gmail.com> - 2014-08-05 07:36 -0400
    Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-05 15:04 +0300
      Re: 3 Suggestions to Make Python Easier For Children Skip Montanaro <skip@pobox.com> - 2014-08-05 07:31 -0500
        Re: 3 Suggestions to Make Python Easier For Children Marko Rauhamaa <marko@pacujo.net> - 2014-08-05 16:19 +0300
          Re: 3 Suggestions to Make Python Easier For Children MRAB <python@mrabarnett.plus.com> - 2014-08-05 15:11 +0100
          Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-06 02:14 +1000
      Re: 3 Suggestions to Make Python Easier For Children Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-08-05 22:43 +1000
        Re: 3 Suggestions to Make Python Easier For Children Chris Angelico <rosuav@gmail.com> - 2014-08-05 23:08 +1000
      Re: 3 Suggestions to Make Python Easier For Children Chris Angelico <rosuav@gmail.com> - 2014-08-05 23:00 +1000

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