Exit with an error on unexpected command line arguments.

Exit with an error on unexpected command line arguments.

BUG=https://code.google.com/p/dart/issues/detail?id=13043
R=alanknight@google.com

Committed: https://code.google.com/p/dart/source/detail?r=28612

[Bob Nystrom, 2013-10-11 21:25:13]

Alan, if you have a few minutes to take a look at this, I would definitely
appreciate it. Thanks!

[Alan Knight, 2013-10-11 22:51:39]

lgtm

[Bob Nystrom, 2013-10-14 21:19:56]

Committed patchset #1 manually as r28612 (presubmit successful).

[nweiz, 2013-10-16 21:46:32]

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
File sdk/lib/_internal/pub/lib/src/command.dart (right):

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:57: bool get requiresEntrypoint =>
true;
Why is this a getter now?

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:126: log.error('Command does not take
any arguments.');
Include the command name.

[Bob Nystrom, 2013-10-29 01:02:12]

Thanks! Revised here: https://codereview.chromium.org/49453003

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
File sdk/lib/_internal/pub/lib/src/command.dart (right):

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:57: bool get requiresEntrypoint =>
true;
On 2013/10/16 21:46:32, nweiz wrote:
> Why is this a getter now?

Kind of pedantic here, but there's no point in adding state to each instance for
this when all instances will have the same value. A getter makes it explicit
that it's a property of the class.

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:126: log.error('Command does not take
any arguments.');
On 2013/10/16 21:46:32, nweiz wrote:
> Include the command name.

Done.

[nweiz, 2013-10-29 19:21:32]

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
File sdk/lib/_internal/pub/lib/src/command.dart (right):

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:57: bool get requiresEntrypoint =>
true;
On 2013/10/29 01:02:12, Bob Nystrom wrote:
> On 2013/10/16 21:46:32, nweiz wrote:
> > Why is this a getter now?
> 
> Kind of pedantic here, but there's no point in adding state to each instance
for
> this when all instances will have the same value. A getter makes it explicit
> that it's a property of the class.

I don't think this communicates what you're trying to communicate. The Dart
language takes pains to make fields and getters interchangeable, so when I see a
(more verbose) getter somewhere where a field would do, I don't read that as
saying "all instances will have the same value", since that would be true for a
final field as well. I just read it as confusing.

If there's a significant memory benefit to be had by not allocating space for
the constant field, I'm sure the VM is smart enough to do that on its own.

[Bob Nystrom, 2013-10-29 19:43:41]

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
File sdk/lib/_internal/pub/lib/src/command.dart (right):

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:57: bool get requiresEntrypoint =>
true;
On 2013/10/29 19:21:33, nweiz wrote:
> On 2013/10/29 01:02:12, Bob Nystrom wrote:
> > On 2013/10/16 21:46:32, nweiz wrote:
> > > Why is this a getter now?
> > 
> > Kind of pedantic here, but there's no point in adding state to each instance
> for
> > this when all instances will have the same value. A getter makes it explicit
> > that it's a property of the class.
> 
> I don't think this communicates what you're trying to communicate. The Dart
> language takes pains to make fields and getters interchangeable, so when I see
a
> (more verbose) getter somewhere where a field would do, I don't read that as
> saying "all instances will have the same value", since that would be true for
a
> final field as well. I just read it as confusing.
> 
> If there's a significant memory benefit to be had by not allocating space for
> the constant field, I'm sure the VM is smart enough to do that on its own.

For me, this isn't an optimization issue. I don't like state in general because
it makes code harder to reason about. I try to minimize the amount of state a
program has. In this case, each instance doesn't need a field so I'd rather use
a getter.

[nweiz, 2013-10-29 21:03:08]

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
File sdk/lib/_internal/pub/lib/src/command.dart (right):

https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
sdk/lib/_internal/pub/lib/src/command.dart:57: bool get requiresEntrypoint =>
true;
On 2013/10/29 19:43:42, Bob Nystrom wrote:
> On 2013/10/29 19:21:33, nweiz wrote:
> > On 2013/10/29 01:02:12, Bob Nystrom wrote:
> > > On 2013/10/16 21:46:32, nweiz wrote:
> > > > Why is this a getter now?
> > > 
> > > Kind of pedantic here, but there's no point in adding state to each
instance
> > for
> > > this when all instances will have the same value. A getter makes it
explicit
> > > that it's a property of the class.
> > 
> > I don't think this communicates what you're trying to communicate. The Dart
> > language takes pains to make fields and getters interchangeable, so when I
see
> a
> > (more verbose) getter somewhere where a field would do, I don't read that as
> > saying "all instances will have the same value", since that would be true
for
> a
> > final field as well. I just read it as confusing.
> > 
> > If there's a significant memory benefit to be had by not allocating space
for
> > the constant field, I'm sure the VM is smart enough to do that on its own.
> 
> For me, this isn't an optimization issue. I don't like state in general
because
> it makes code harder to reason about. I try to minimize the amount of state a
> program has. In this case, each instance doesn't need a field so I'd rather
use
> a getter.

A final field with a constant value isn't state. It can't change in any way
ever, and that's clear from looking at the declaration. It's identical to a
getter, both in terms of language semantics and what the declarations
communicate. The only difference is that a getter is more verbose and thus
confusing to a reader looking for a reason for that verbosity.

[Bob Nystrom, 2013-10-29 21:11:08]

On 2013/10/29 21:03:08, nweiz wrote:
>
https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
> File sdk/lib/_internal/pub/lib/src/command.dart (right):
> 
>
https://codereview.chromium.org/27000011/diff/1/sdk/lib/_internal/pub/lib/src...
> sdk/lib/_internal/pub/lib/src/command.dart:57: bool get requiresEntrypoint =>
> true;
> On 2013/10/29 19:43:42, Bob Nystrom wrote:
> > On 2013/10/29 19:21:33, nweiz wrote:
> > > On 2013/10/29 01:02:12, Bob Nystrom wrote:
> > > > On 2013/10/16 21:46:32, nweiz wrote:
> > > > > Why is this a getter now?
> > > > 
> > > > Kind of pedantic here, but there's no point in adding state to each
> instance
> > > for
> > > > this when all instances will have the same value. A getter makes it
> explicit
> > > > that it's a property of the class.
> > > 
> > > I don't think this communicates what you're trying to communicate. The
Dart
> > > language takes pains to make fields and getters interchangeable, so when I
> see
> > a
> > > (more verbose) getter somewhere where a field would do, I don't read that
as
> > > saying "all instances will have the same value", since that would be true
> for
> > a
> > > final field as well. I just read it as confusing.
> > > 
> > > If there's a significant memory benefit to be had by not allocating space
> for
> > > the constant field, I'm sure the VM is smart enough to do that on its own.
> > 
> > For me, this isn't an optimization issue. I don't like state in general
> because
> > it makes code harder to reason about. I try to minimize the amount of state
a
> > program has. In this case, each instance doesn't need a field so I'd rather
> use
> > a getter.
> 
> A final field with a constant value isn't state. It can't change in any way
> ever, and that's clear from looking at the declaration.

State doesn't have to be mutable.

> It's identical to a getter, both in terms of language semantics and what the
declarations
> communicate.

Well, it isn't identical in what it communicates to *me*, or I wouldn't have
changed it.

- bob

[nweiz, 2013-10-29 21:51:22]

On 2013/10/29 21:11:08, Bob Nystrom wrote:
> State doesn't have to be mutable.

If a value is immutable and constant across all instances, it's not state -- at
least not instance-level state. It doesn't matter how you declare it. Saying
"final" doesn't make it work any differently than saying "get" does.

> > It's identical to a getter, both in terms of language semantics and what the
> declarations
> > communicate.
> 
> Well, it isn't identical in what it communicates to *me*, or I wouldn't have
> changed it.

I think your intuition here is very idiosyncratic. If I understand you
correctly, you feel that using a getter communicates more strongly that all
instances will return the same value for requiresEntrypoint. But I think any
other reader familiar with the Dart language would understand that perfectly
clearly from the declaration "final requiresEntrypoint = true", by virtue of the
fact that the language semantics guarantee it. And not by some obscure
corner-case; that's explicitly what "final" means.

[nweiz, 2013-10-29 23:20:38]

LGTM