0.8.4: stadlib in Lyng! added universal Iterable functions

docs/Iterable.md

@@ -17,7 +17,14 @@ Iterator itself is a simple interface that should provide only to method:
 
 Just remember at this stage typed declarations are not yet supported.
 
-Having `Iterable` in base classes allows to use it in for loop. Also, each `Iterable` has some utility functions available:
+Having `Iterable` in base classes allows to use it in for loop. Also, each `Iterable` has some utility functions available, for example
+
+    val r = 1..10  // Range is Iterable!  
+    assertEquals( [9,10] r.takeLast(2) )
+    assertEquals( [1,2,3] r.take(3) )
+    assertEquals( [9,10] r.drop(8) )
+    assertEquals( [1,2] r.dropLast(8) )
+    >>> void
 
 ## Instance methods
 
@@ -33,7 +40,15 @@ Having `Iterable` in base classes allows to use it in for loop. Also, each `Iter
 | map(f)          | create a list of values returned by `f` called for each element of the iterable |
 | indexOf(i)      | return index if the first encounter of i or a negative value if not found       |
 | associateBy(kf) | create a map where keys are returned by kf that will be called for each element |
+| first           | first element (1)                                                               |
+| last            | last element (1)                                                                |
+| take(n)         | return [Iterable] of up to n first elements                                     |
+| taleLast(n)     | return [Iterable] of up to n last elements                                      |
+| drop(n)         | return new [Iterable] without first n elements                                  |
+| dropLast(n)     | return new [Iterable] without last n elements                                   |
 
+(1)
+: throws `NoSuchElementException` if there is no such element 
 
     fun Iterable.toList(): List
     fun Iterable.toSet(): Set

docs/RingBuffer.md

@@ -0,0 +1,52 @@
+# RingBuffer
+
+This is a fixed size buffer that allow to store N last elements with _O(1)_ effectiveness (no data shifting).
+
+Here is the sample:
+
+    val r = RingBuffer(3)
+    assert( r is RingBuffer )
+    assertEquals(0, r.size)
+    assertEquals(3, r.capacity)
+    
+    r += 10
+    assertEquals(1, r.size)
+    assertEquals(10, r.first)
+    
+    r += 20
+    assertEquals(2, r.size)
+    assertEquals( [10, 20], r.toList() )
+    
+    r += 30
+    assertEquals(3, r.size)
+    assertEquals( [10, 20, 30], r.toList() )
+    
+    // now first value is lost:
+    r += 40
+    assertEquals(3, r.size)
+    assertEquals( [20, 30, 40], r.toList() )
+    assertEquals(3, r.capacity)
+
+    >>> void
+
+Ring buffer implements [Iterable], so any of its methods are available for `RingBuffer`, e.g. `first`, `last`, `toList`,
+`take`, `drop`, `takelast`, `dropLast`, etc.
+
+## Constructor
+
+    RinbBuffer(capacity: Int)
+
+## Instance methods
+
+| method      | description            | remarks |
+|-------------|------------------------|---------|
+| capacity    | max size of the buffer |         |
+| size        | current size           | (1)     |
+| operator += | add new item           | (1)     |
+| add(item)   | add new item           | (1)     |
+| iterator()  | return iterator        | (1)     |
+
+(1)
+: Ringbuffer is not threadsafe, protect it with a mutex to avoid RC where necessary.
+
+[Iterable]: Iterable.md

docs/parallelism.md

@@ -189,3 +189,19 @@ Important difference from the channels or like, every time you collect the flow,
 
 Notice that flow's lambda is not called until actual collection is started. Cold flows are
 better in terms of resource consumption.
+
+Flows allow easy transforming of any [Iterable]. See how the standard Lyng library functions use it:
+
+    fun Iterable.filter(predicate) {
+        val list = this
+        flow {
+            for( item in list ) {
+                if( predicate(item) ) {
+                    emit(item)
+                }
+            }
+        }
+    }
+
+
+[Iterable]: Iterable.md

docs/tutorial.md

@@ -14,8 +14,9 @@ __Other documents to read__ maybe after this one:
 - [Advanced topics](advanced_topics.md), [declaring arguments](declaring_arguments.md)
 - [OOP notes](OOP.md), [exception handling](exceptions_handling.md)
 - [math in Lyng](math.md)
+- [time](time.md) and [parallelism](parallelism.md)
 - [parallelism] - multithreaded code, coroutines, etc.
-- Some class references: [List], [Set], [Map], [Real], [Range], [Iterable], [Iterator], [time manipulation](time.md)
+- Some class references: [List], [Set], [Map], [Real], [Range], [Iterable], [Iterator], [time manipulation](time.md), [RingBuffer], [Buffer].
 - Some samples: [combinatorics](samples/combinatorics.lyng.md), national vars and
   loops: [сумма ряда](samples/сумма_ряда.lyng.md). More at [samples folder](samples)
 
@@ -1304,4 +1305,6 @@ See [math functions](math.md). Other general purpose functions are:
 
 [Buffer]: Buffer.md
 
-[parallelism]: parallelism.md
+[parallelism]: parallelism.md
+
+[RingBuffer]: RingBuffer.md