Sequence (Iterator) Utilities for Golang

Golang's "missing" iterator/sequence functions.

iter.Seq helpers

• With(...T) iter.Seq[T] : Construct a sequence using the provided values;
• FromChan(<-chan) iter.Seq[T]: Returns a sequence that produces values until the channel is closed;
• ToChan(iter.Seq[T]) <-chan: Returns a channel that produces values until the sequence is exhausted;
• ToChanCtx(context.Context, iter.Seq[T]) <-chan: Returns a channel that produces values until the sequence is exhausted or the context is canceled;
• Map(iter.Seq[T], func(T) O) iter.Seq[O]: Maps the items in the sequence to another type;
• Append(iter.Seq[T], ...T) iter.Seq[T]: Returns a new sequence that includes the items from the passed sequence, plus the additional items;
• Filter(iter.Seq[T], func(T) bool) iter.Seq[T]: Filter the values in the sequence by applying fn to each value;
• IterKV(iter.Seq[T], func(V) K) iter.Seq2[K,V]: ...

iter.Seq2 helpers

Some of these helpers use seq.KV, some do not. I've generally tried to use seq.KV when it would:

1. easily be confusing to deal with keys and values as separate values
2. when they have to be paired together to avoid having to handle odd numbers of input

• WithKV(...KV[K,V]) : Construct a key-value (iter.Seq2) sequence using the provided key-values;
• MapKV(iter.Seq2[K,V], func(K,V) (K1,V1)) iter.Seq2[K1,V2]: Maps the items in the sequence to other types;
• AppendKV(iter.Seq2[K,V], ...KV[K,V]) iter.Seq2[K,V]: Returns a new sequence that includes the items from the passed sequence, plus the additional KV pairs;
• FilterKV(iter.Seq2[K,V], func(K,V) bool) iter.Seq2[K,V]: Filter the values in the sequence by applying fn to each value;