List interface contains a last method but not a first method

[jacob314]

The Dart List interface contains a last method but not a first method.

I believe it would be consistent with dart if the last and first methods were changed to properties instead of methods as calculating last and first should be extremely cheap for typical implementations.

[alan-knight]

Moving from jjb. lrn, if you'd rather I moved these elsewhere, or didn't move them, let me know.

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Set owner to @lrhn.

[lrhn]

The "last" method (which I agree should be a getter) is a shorthand for
 list[list.length-1] , which is a (somewhat) long and annoyingly repetitive expression.
When such an expression is used often, it's a good candidate for a shorthand.

For "first", it would always be list[0], which doesn't need a shorthand as much.

Lists are asymmetric - they start from zero, but can have arbitrary lengths. They are designed for random access and growing at the end (a linked list might not be best modelled as a Dart List, but perhaps as a Stack/Queue/DoubleEndedQueue instead). That's why we have "last", "add[Last]" (the "addLast" should be dropped) and "removeLast" as shorthands - we often need to work on that end of the list.

There are generic list[0], list.removeAt(0), list.insertAt(0, e) that works everywhere, and they don't really need a shorthand like acting on the element at position (list.length-1) do. If we had negative-indexing, so -1 was equivalent to (list.length-1), we wouldn't need the 'last' shorthands either (not that there is any plan for that, it's just an example).

That said, if it makes often written code easier to read, it does have merit (I'm in favor of having both isEmpty and hasElements). I'll keep this open as a reminder (and star-counter) for this suggestion.

It's fine assigning to me. I'll try to collect all these suggestions for the "collections overhaul", hopefully somewhere before M2.

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Removed Type-Defect label.
Added Type-Enhancement label.

[floitschG]

Fixed in r15040.

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Added Fixed label.