Add Iterable.fold (and Stream.fold) which replace `reduce`.

Add Iterable.fold (and Stream.fold) which replace `reduce`.

For now this is just a copy. In a next step we will change the behavior of
`reduce`.

BUG= http://dartbug.com/9536

Committed: https://code.google.com/p/dart/source/detail?r=20978

[kevmoo-old, 2013-04-03 17:45:51]

DBC

https://codereview.chromium.org/13548002/diff/1/sdk/lib/core/iterable.dart
File sdk/lib/core/iterable.dart (right):

https://codereview.chromium.org/13548002/diff/1/sdk/lib/core/iterable.dart#ne...
sdk/lib/core/iterable.dart:106: * an initial value: `iterable.reduce(min)`. Use
[fold] instead.
I'd actually mark this API as @deprecated.

It cannot be used in its new form yet.
The current form is going to die, breaking current users in the process.
Better for current users to get the deprecation warnings in editor/analyzer.
This comment will be easy to miss for folks w/ big libraries.

Although keep the comment that reduce will be reborn w/ a new behavior. That's
goodness.

[Lasse Reichstein Nielsen, 2013-04-04 08:35:18]

lgtm

https://codereview.chromium.org/13548002/diff/1/sdk/lib/core/iterable.dart
File sdk/lib/core/iterable.dart (right):

https://codereview.chromium.org/13548002/diff/1/sdk/lib/core/iterable.dart#ne...
sdk/lib/core/iterable.dart:106: * an initial value: `iterable.reduce(min)`. Use
[fold] instead.
Agree. Mark as deprecated. Anyone using the current version is doing it wrong.

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_map_test.dart
File tests/corelib/list_map_test.dart (right):

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_map_test.d...
tests/corelib/list_map_test.dart:118: testOp((i) => i.reduce(0, (a, b) => a +
b), "reduce-sum");
Remove the reduce line. It's deprecated.

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_reversed_t...
File tests/corelib/list_reversed_test.dart (right):

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_reversed_t...
tests/corelib/list_reversed_test.dart:109: testOp((i) => i.reduce(0, (a, b) => a
+ b), "reduce-sum");
Remove reduce.

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/CssClassSet.dart
File tools/dom/src/CssClassSet.dart (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/CssClassSet.dar...
tools/dom/src/CssClassSet.dart:63: return readClasses().reduce(initialValue,
combine);
call fold or readClasses().fold here.

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/WrappedList.dart
File tools/dom/src/WrappedList.dart (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/WrappedList.dar...
tools/dom/src/WrappedList.dart:31: _list.reduce(initialValue, combine);
Call fold or _list.fold.

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
File tools/dom/templates/html/impl/impl_Element.darttemplate (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
tools/dom/templates/html/impl/impl_Element.darttemplate:162: return
IterableMixinWorkaround.reduce(this, initialValue, combine);
And don't use reduce here.

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
File tools/dom/templates/html/impl/impl_Node.darttemplate (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
tools/dom/templates/html/impl/impl_Node.darttemplate:150: return
IterableMixinWorkaround.reduce(this, initialValue, combine);
and here.

[floitsch, 2013-04-05 16:10:02]

https://codereview.chromium.org/13548002/diff/1/sdk/lib/core/iterable.dart
File sdk/lib/core/iterable.dart (right):

https://codereview.chromium.org/13548002/diff/1/sdk/lib/core/iterable.dart#ne...
sdk/lib/core/iterable.dart:106: * an initial value: `iterable.reduce(min)`. Use
[fold] instead.
On 2013/04/03 17:45:51, kevmoo wrote:
> I'd actually mark this API as @deprecated.
> 
> It cannot be used in its new form yet.
> The current form is going to die, breaking current users in the process.
> Better for current users to get the deprecation warnings in editor/analyzer.
> This comment will be easy to miss for folks w/ big libraries.
> 
> Although keep the comment that reduce will be reborn w/ a new behavior. That's
> goodness.

Done.

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_map_test.dart
File tests/corelib/list_map_test.dart (right):

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_map_test.d...
tests/corelib/list_map_test.dart:118: testOp((i) => i.reduce(0, (a, b) => a +
b), "reduce-sum");
On 2013/04/04 08:35:18, Lasse Reichstein Nielsen wrote:
> Remove the reduce line. It's deprecated.

I prefer keeping it. When I change the reduce to the new behavior I will get an
error during tests and make sure to add a new test-case.

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_reversed_t...
File tests/corelib/list_reversed_test.dart (right):

https://codereview.chromium.org/13548002/diff/1/tests/corelib/list_reversed_t...
tests/corelib/list_reversed_test.dart:109: testOp((i) => i.reduce(0, (a, b) => a
+ b), "reduce-sum");
On 2013/04/04 08:35:18, Lasse Reichstein Nielsen wrote:
> Remove reduce.

ditto: I prefer getting an error, that I need to update the test.

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/CssClassSet.dart
File tools/dom/src/CssClassSet.dart (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/CssClassSet.dar...
tools/dom/src/CssClassSet.dart:63: return readClasses().reduce(initialValue,
combine);
On 2013/04/04 08:35:18, Lasse Reichstein Nielsen wrote:
> call fold or readClasses().fold here.

Since we are in a 'reduce' I prefer to call to reduce. When the semantics of
reduce change, I only need to change the number of arguments.

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/WrappedList.dart
File tools/dom/src/WrappedList.dart (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/src/WrappedList.dar...
tools/dom/src/WrappedList.dart:31: _list.reduce(initialValue, combine);
On 2013/04/04 08:35:18, Lasse Reichstein Nielsen wrote:
> Call fold or _list.fold.

We are in a reduce. I prefer calling 'reduce'.

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
File tools/dom/templates/html/impl/impl_Element.darttemplate (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
tools/dom/templates/html/impl/impl_Element.darttemplate:162: return
IterableMixinWorkaround.reduce(this, initialValue, combine);
On 2013/04/04 08:35:18, Lasse Reichstein Nielsen wrote:
> And don't use reduce here.

ditto. We are in a reduce, so nothing is gained by calling something else.

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
File tools/dom/templates/html/impl/impl_Node.darttemplate (right):

https://codereview.chromium.org/13548002/diff/1/tools/dom/templates/html/impl...
tools/dom/templates/html/impl/impl_Node.darttemplate:150: return
IterableMixinWorkaround.reduce(this, initialValue, combine);
On 2013/04/04 08:35:18, Lasse Reichstein Nielsen wrote:
> and here.

ditto.

[floitsch, 2013-04-05 16:13:33]

Committed patchset #2 manually as r20978 (presubmit successful).

[nweiz, 2013-04-10 20:32:18]

On 2013/04/05 16:13:33, floitsch wrote:
> Committed patchset #2 manually as r20978 (presubmit successful).

Why weren't Bob and I cced on this? It touched our code, and in fact seems to
have broken our users:
https://groups.google.com/a/dartlang.org/forum/?fromgroups=#!topic/misc/NB4x7...