diff options
| -rw-r--r-- | src/pkg/exp/iterable/iterable.go | 33 |
1 files changed, 17 insertions, 16 deletions
diff --git a/src/pkg/exp/iterable/iterable.go b/src/pkg/exp/iterable/iterable.go index 416a70836..aefff9427 100644 --- a/src/pkg/exp/iterable/iterable.go +++ b/src/pkg/exp/iterable/iterable.go @@ -133,14 +133,15 @@ func Partition(iter Iterable, f func(interface{}) bool) (Iterable, Iterable) { return Filter(iter, f), Filter(iter, not(f)) } -// helper type for the Take/TakeWhile/Drop/DropWhile functions. -// primarily used so that the .Iter() method can be attached -type iterFunc func(chan<- interface{}) +// A Func is a function that, when called, sends the +// iterable values on a channel. +type Func func(chan<- interface{}) -// provide the Iterable interface -func (v iterFunc) Iter() <-chan interface{} { +// Iter creates and returns a new channel; it starts a +// goroutine running f to send values to the channel. +func (f Func) Iter() <-chan interface{} { ch := make(chan interface{}) - go v(ch) + go f(ch) return ch } @@ -149,7 +150,7 @@ func Take(iter Iterable, n int) Iterable { return Slice(iter, 0, n) } // TakeWhile returns an Iterable that contains elements from iter while f is true. func TakeWhile(iter Iterable, f func(interface{}) bool) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { for v := range iter.Iter() { if !f(v) { break @@ -162,7 +163,7 @@ func TakeWhile(iter Iterable, f func(interface{}) bool) Iterable { // Drop returns an Iterable that returns each element of iter after the first n elements. func Drop(iter Iterable, n int) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { m := n for v := range iter.Iter() { if m > 0 { @@ -177,7 +178,7 @@ func Drop(iter Iterable, n int) Iterable { // DropWhile returns an Iterable that returns each element of iter after the initial sequence for which f returns true. func DropWhile(iter Iterable, f func(interface{}) bool) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { drop := true for v := range iter.Iter() { if drop { @@ -194,7 +195,7 @@ func DropWhile(iter Iterable, f func(interface{}) bool) Iterable { // Cycle repeats the values of iter in order infinitely. func Cycle(iter Iterable) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { for { for v := range iter.Iter() { ch <- v @@ -205,7 +206,7 @@ func Cycle(iter Iterable) Iterable { // Chain returns an Iterable that concatentates all values from the specified Iterables. func Chain(args []Iterable) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { for _, e := range args { for v := range e.Iter() { ch <- v @@ -219,7 +220,7 @@ func Chain(args []Iterable) Iterable { // each input Iterable. The length of the returned Iterable is the minimum of // the lengths of the input Iterables. func Zip(args []Iterable) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { defer close(ch) if len(args) == 0 { return @@ -260,7 +261,7 @@ func ZipWith3(f func(d, e, f interface{}) interface{}, a, b, c Iterable) Iterabl // Slice returns an Iterable that contains the elements from iter // with indexes in [start, stop). func Slice(iter Iterable, start, stop int) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { defer close(ch) i := 0 for v := range iter.Iter() { @@ -277,7 +278,7 @@ func Slice(iter Iterable, start, stop int) Iterable { // Repeat generates an infinite stream of v. func Repeat(v interface{}) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { for { ch <- v } @@ -286,7 +287,7 @@ func Repeat(v interface{}) Iterable { // RepeatTimes generates a stream of n copies of v. func RepeatTimes(v interface{}, n int) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { for i := 0; i < n; i++ { ch <- v } @@ -315,7 +316,7 @@ type Grouper interface { // values for the group, and an Iterable for retrieving all the values in the // group. func GroupBy(iter Iterable, k Grouper) Iterable { - return iterFunc(func(ch chan<- interface{}) { + return Func(func(ch chan<- interface{}) { var curkey interface{} var lst *list.List // Basic strategy is to read one group at a time into a list prior to emitting the Group value |