fix #29 mapentries, map iterators, => operator and .toMap()

docs/Map.md

@@ -53,11 +53,57 @@ To iterate maps it is convenient to use `keys` method that returns [Set] of keys
     >>> answer
     >>> void
 
+Or iterate its key-value pairs that are instances of [MapEntry] class:
+
+    val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
+    for( entry in map ) {
+        println("map[%s] = %s"(entry.key, entry.value))
+    }
+    void
+    >>> map[foo] = 1
+    >>> map[bar] = buzz
+    >>> map[42] = answer
+    >>> void
+
+There is a shortcut to use `MapEntry` to create maps: operator `=>` which creates `MapEntry`:
+
+    val entry = "answer" => 42
+    assert( entry is MapEntry )
+    >>> void
+
+And you can use it to construct maps:
+
+    val map = Map( "foo" => 1, "bar" => 22)
+    assertEquals(1, map["foo"])
+    assertEquals(22, map["bar"])
+    >>> void
+
+Or use `.toMap` on anything that implements [Iterable] and which elements implements [Array] with 2 elements size, for example, `MapEntry`:
+
+    val map = ["foo" => 1, "bar" => 22].toMap()
+    assert( map is Map )
+    assertEquals(1, map["foo"])
+    assertEquals(22, map["bar"])
+    >>> void
+
+
 It is possible also to get values as [List] (values are not unique):
 
     val map = Map( ["foo", 1], ["bar", "buzz"], [42, "answer"] )
     assertEquals(map.values, [1, "buzz", "answer"] )
     >>> void
 
+Map could be tested to be equal: when all it key-value pairs are equal, the map
+is equal.
+
+    val m1 = Map(["foo", 1])
+    val m2 = Map(["foo", 1])
+    val m3 = Map(["foo", 2])
+    assert( m1 == m2 )
+    // but the references are different:
+    assert( m1 !== m2 )
+    // different maps:
+    assert( m1 != m3 )
+    >>> void
 
 [Collection](Collection.md)

docs/tutorial.md

@@ -14,7 +14,7 @@ __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)
-- Some class references: [List], [Real], [Range], [Iterable], [Iterator]
+- Some class references: [List], [Set], [Map], [Real], [Range], [Iterable], [Iterator]
 - Some samples: [combinatorics](samples/combinatorics.lyng.md), national vars and loops: [сумма ряда](samples/сумма_ряда.lyng.md). More at [samples folder](samples)
 
 # Expressions
@@ -583,6 +583,28 @@ You can get ranges to extract a portion from a list:
     assertEquals( [2,3], list[1..<3])
     >>> void
 
+# Sets
+
+Set are unordered collection of unique elements, see [Set]. Sets are [Iterable] but have no indexing access.
+
+    assertEquals( Set(3, 2, 1), Set( 1, 2, 3))
+    assert( 5 !in Set(1, 2, 6) )
+    >>> void
+
+Please see [Set] for detailed description.
+
+# Maps
+
+Maps are unordered collection of key-value pairs, where keys are unique. See [Map] for details. Map also
+are [Iterable]:
+
+    val m = Map( "foo" => 77, "bar" => "buzz" )
+    assertEquals( m["foo"], 77 )
+    >>> void
+
+Please see [Map] reference for detailed description on using Maps.
+
+
 # Flow control operators
 
 ## if-then-else
@@ -1172,3 +1194,5 @@ See [math functions](math.md). Other general purpose functions are:
 [Range]: Range.md
 [String]: String.md
 [string formatting]: https://github.com/sergeych/mp_stools?tab=readme-ov-file#sprintf-syntax-summary
+[Set]: Set.md
+[Map]: Map.md