Ideas for additional methods

[gammazero]

Continued from #28, from @rickb777

Here are some ideas for methods that you could add:

• push and insert slices - i.e. internalise the loop needed and reduce loop overhead
• add adaptors for the PopBack, PopFront and At methods to provide iterators (Go 1.23)
• add Full() bool method - a shortcut for q.Len() == q.Cap() which would be useful for anyone wanting to impose a maximum size or avoid resizing

[gammazero]

@rickb777
A PushSlice and InsertSlice are probably not needed, since they seem like an uncommon operation and their purpose, aside from some syntactic convenience, is to avoid possible multiple resizes when adding a number of items. The caller can already do this using the Grow function:

q.Grow(len(elems))
for i := range elems {
    q.PushBack(elems[i])
}

Adding iterator adaptors IterPopFront and IterPopBack, might be unnecessary when the caller can already do:

for q.Len() != 0 {
    process(q.PopFront())
}

The iterator looks like:

for item := range IterPopFront() {
    process(item)
}

So it does not really simplify the code. However, it may still be worth adding these iterators to eliminate intermediate resizes during iteration. Somewhat like the inverse of Grow. See PR #32.

As for a Full function, it seems like it is syntactic sugar for something that is likely not very common. I think if q.Len() == q.Cap() is a bit more explicit. If a size limit is desired them it might be better wrap Deque in a type that checks if Len is at the limit when adding items. The wrapper's PushBask can then return a bool or error to indicate that the limit has been reached. If it is necessary to block on a write to a full Deque, or a read from an empty Deque, then channelqueue does exactly this. WDYT?