feedback on Improved default constructors
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Seth Ladd
Oct 10, 2015, 3:23:44 PM10/10/15
to Dart Core Development
Hi,
Noticed that in the latest notes, there was a bit of discussion around "Improved default constructors" (https://groups.google.com/a/dartlang.org/forum/#!topic/core-dev/cQZlx90c7z0)
You might want to see how Flutter is being used, as it might provide some real-world examples of constructing nested object graphs. If there's ever a case for an improved syntax for constructing trees of objects, I'm not sure what is :)
For example:
await showDialog(navigator, (NavigatorState navigator) {
return new Dialog(
title: new Text('Not Implemented'),
content: new Text('This feature has not yet been implemented.'),
actions: [
new FlatButton(
child: new Row([
new Icon(
type: 'device/dvr',
size: 18
),
new Container(
width: 8.0
),
new Text('DUMP APP TO CONSOLE'),
]),
onPressed: () { debugDumpApp(); }
),
new FlatButton(
child: new Text('OH WELL'),
onPressed: () {
navigator.pop(false);
}
),
]
return new Material(
type: MaterialType.canvas,
child: new ScrollableViewport(
child: new Container(
padding: const EdgeDims.symmetric(vertical: 20.0),
child: new BlockBody([
new DrawerItem(
icon: 'action/thumb_up',
onPressed: () => _confirmOptimismChange(),
child: new Row([
new Flexible(child: new Text('Everything is awesome')),
new Checkbox(
value: config.optimism == StockMode.optimistic,
onChanged: (_) => _confirmOptimismChange()
),
])
),
new DrawerItem(
icon: 'action/backup',
onPressed: () { _handleBackupChanged(!(config.backup == BackupMode.enabled)); },
child: new Row([
new Flexible(child: new Text('Back up stock list to the cloud')),
new Switch(
value: config.backup == BackupMode.enabled,
onChanged: _handleBackupChanged
),
])
),
])
)
)
Thanks for taking a look!
Seth
krupal shah
May 13, 2016, 11:46:02 AM5/13/16
to Dart Core Development
Sorry but this syntax of flutter looks like a callback hell.
Lasse R.H. Nielsen
May 13, 2016, 5:56:49 PM5/13/16
to Seth Ladd, Dart Core Development
Let's see if we can make that more readable.
First, let's remove "new" (and the unnecessary eta-expansion of debugDumpApp).
return Dialog(
title: Text('Not Implemented'),
content: Text('This feature has not yet been implemented.'),
actions: [
FlatButton(
child: Row([
Icon(
type: 'device/dvr',
size: 18
),
Container(
width: 8.0
),
Text('DUMP APP TO CONSOLE'),
]),
onPressed: debugDumpApp
),
FlatButton(
child: Text('OH WELL'),
onPressed: () {
navigator.pop(false);
}
),
])
It's already more *readable*, but not really shorter (in height). It does give make it feel more natural to put some of the parameters on the same line. I guess there isn't much more to do with the available constructors - the remaining information is necessary.
More specialized constructors might allow some of the named parameters to be positional, it seems a little odd that all parameters are optional and named. I'd expect a FlatButton to always have a child and onPressed, so one or both of those could be a non-optional position parameter.
I'd expect something formatted like:
return Dialog(
title: Text('Not Implemented'),
content: Text('This feature has not yet been implemented.'),
actions: [
FlatButton(Row([
Icon(type: 'device/dvr', size: 18),
Container(width: 8.0),
Text('DUMP APP TO CONSOLE'),
]),
onPressed: debugDumpApp
),
FlatButton(Text('OH WELL'), onPressed: () {
navigator.pop(false);
}),
]);
I think that is already a very improved syntax, and it's just removing the "new" and reformatting a bit.
If our dart-formatter creates the mess above, then maybe it should be more compact - especially the "Container" argument shouldn't be on a line by its own. Maybe it's manually formatted for consistency, not readability (which can be, but isn't always, the same).
/L
--
Lasse R.H. Nielsen - l...@google.com
'Faith without judgement merely degrades the spirit divine'
Google Denmark ApS - Frederiksborggade 20B, 1 sal - 1360 København K - Denmark - CVR nr. 28 86 69 84
Google Denmark ApS - Frederiksborggade 20B, 1 sal - 1360 København K - Denmark - CVR nr. 28 86 69 84
Natalie Weizenbaum
May 13, 2016, 8:20:48 PM5/13/16
to Lasse R.H. Nielsen, Seth Ladd, Dart Core Development
Flutter doesn't use the formatter, but if they did, here's the sort of output they'd get.
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Lasse R.H. Nielsen
May 14, 2016, 6:33:02 AM5/14/16
to Natalie Weizenbaum, Seth Ladd, Dart Core Development
On Sat, May 14, 2016 at 2:20 AM, Natalie Weizenbaum <nw...@google.com> wrote:
Flutter doesn't use the formatter, but if they did, here's the sort of output they'd get.
Thanks. Yes, that's a lot more readable. Score one for formatter :)
/L
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Lasse R.H. Nielsen - l...@google.com
'Faith without judgement merely degrades the spirit divine'
Google Denmark ApS - Frederiksborggade 20B, 1 sal - 1360 København K - Denmark - CVR nr. 28 86 69 84
Google Denmark ApS - Frederiksborggade 20B, 1 sal - 1360 København K - Denmark - CVR nr. 28 86 69 84
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