I propose to use Sven���s version for #sum:ifEmpty:. The result would be these three methods:

sum

^ self

sum: [ :each | each ]

ifEmpty: [ 0 ]

sum: aBlock

^ self

sum: aBlock

ifEmpty: [ self errorEmptyCollection ]

sum: aBlock ifEmpty: emptyBlock

| sum sample |

self isEmpty ifTrue: [ ^ emptyBlock value ].

sample := self anyOne.

sum := self

inject: sample

into: [ :accum :each | accum + (aBlock value: each) ].

^ sum - sample

I���ve attached a couple of benchmark results below. To me they show that

1. the new implementation is maybe a tiny bit slower but insignificantly so (if you���re going for performance you���ll probably write your own optimised version anyway)

2. there is no need to duplicate the code (like #sum and #sum: currently do). It���s perfectly fine to delegate to #sum:ifEmpty:

In addition to the above changes I would like to remove #detectSum: (-> #sum:) and #sumNumbers (-> #sum).

Note that once we agree on changing this API, we will need to also change #detectMin:, #detectMax:, #min, #max as well as all overrides (e.g. RunArray, Interval) of these and of #sum et. al. to stay consistent. The changes would of course be in line with this change, such that every operation has a unary selector with a sensible default, one that takes a block and throws an error for empty collections and a third that takes a block for the iteration and one for the empty case.

Please cast your vote for these changes:

1. Do you agree to changing #sum and #sum: in the suggested way?

2. Do you agree to the removal of #detectSum:?

3. Do you agree to the removal of #sumNumbers?

4. Do you agree that the #max and #min selectors also need to be adapted?

Thanks for you help.

Cheers,

Max

Benchmarks

============

(Note that these aren���t very good benchmarks. There���s quite some variation on each run.)

Machine:

MacBook Pro (15-inch, Early 2011)

CPU:��2.2 GHz Intel Core i7

Memory:��8 GB 1333 MHz DDR3

Disk:��APPLE SSD TS512C (500 GB)

Benchmarks of the current versions:

[ (1 to: 1000000) asArray sum ] benchFor: 10 seconds.

75 iterations,��7.470 per second

[ (1 to: 1000000) asArray sum: [ :e | e ] ] benchFor: 10 seconds.

72 iterations,��7.128 per second

[ (1 to: 100) asArray sum ] benchFor: 10 seconds.

1,189,477 iterations, 118,912 per second

[ (1 to: 100) asArray sum: [ :e | e ] ] benchFor: 10 seconds.

1,171,467 iterations, 117,112 per second

Benchmarks of the new versions:

[ (1 to: 1000000) asArray sum ] benchFor: 10 seconds.

73 iterations, 7.244 per second

[ (1 to: 1000000) asArray sum: [ :e | e ] ] benchFor: 10 seconds.

75 iterations, 7.480 per second

[ (1 to: 1000000) asArray sum: [ :e | e ] ifEmpty: [ 0 ] ] benchFor: 10 seconds.

72 iterations, 7.141 per second

[ (1 to: 100) asArray sum ] benchFor: 10 seconds.

1,115,827 iterations, 111,560 per second

[ (1 to: 100) asArray sum: [ :e | e ] ] benchFor: 10 seconds.

1,154,595 iterations, 115,425 per second

[ (1 to: 100) asArray sum: [ :e | e ] ifEmpty: [ 0 ] ] benchFor: 10 seconds.

1,102,358 iterations, 110,203 per second