feat(Go-Tool)：2020/11/12:新增linq包使用示例(未完成)

2020-11-12 18:10:15 +08:00
parent 3616c4b5e5
commit 2ac2b2666f
33 changed files with 2517 additions and 0 deletions
@@ -0,0 +1,151 @@
+package linq
+
+// SelectMany projects each element of a collection to a Query, iterates and
+// flattens the resulting collection into one collection.
+func (q Query) SelectMany(selector func(interface{}) Query) Query {
+	return Query{
+		Iterate: func() Iterator {
+			outernext := q.Iterate()
+			var inner interface{}
+			var innernext Iterator
+
+			return func() (item interface{}, ok bool) {
+				for !ok {
+					if inner == nil {
+						inner, ok = outernext()
+						if !ok {
+							return
+						}
+
+						innernext = selector(inner).Iterate()
+					}
+
+					item, ok = innernext()
+					if !ok {
+						inner = nil
+					}
+				}
+
+				return
+			}
+		},
+	}
+}
+
+// SelectManyIndexed projects each element of a collection to a Query, iterates and
+// flattens the resulting collection into one collection.
+//
+// The first argument to selector represents the zero-based index of that element
+// in the source collection. This can be useful if the elements are in a known order
+// and you want to do something with an element at a particular index, for example.
+// It can also be useful if you want to retrieve the index of one or more elements.
+// The second argument to selector represents the element to process.
+func (q Query) SelectManyIndexed(selector func(int, interface{}) Query) Query {
+	return Query{
+		Iterate: func() Iterator {
+			outernext := q.Iterate()
+			index := 0
+			var inner interface{}
+			var innernext Iterator
+
+			return func() (item interface{}, ok bool) {
+				for !ok {
+					if inner == nil {
+						inner, ok = outernext()
+						if !ok {
+							return
+						}
+
+						innernext = selector(index, inner).Iterate()
+						index++
+					}
+
+					item, ok = innernext()
+					if !ok {
+						inner = nil
+					}
+				}
+
+				return
+			}
+		},
+	}
+}
+
+// SelectManyBy projects each element of a collection to a Query, iterates and
+// flattens the resulting collection into one collection, and invokes
+// a result selector function on each element therein.
+func (q Query) SelectManyBy(
+	selector func(interface{}) Query,
+	resultSelector func(interface{}, interface{}) interface{},
+) Query {
+
+	return Query{
+		Iterate: func() Iterator {
+			outernext := q.Iterate()
+			var outer interface{}
+			var innernext Iterator
+
+			return func() (item interface{}, ok bool) {
+				for !ok {
+					if outer == nil {
+						outer, ok = outernext()
+						if !ok {
+							return
+						}
+
+						innernext = selector(outer).Iterate()
+					}
+
+					item, ok = innernext()
+					if !ok {
+						outer = nil
+					}
+				}
+
+				item = resultSelector(outer, item)
+				return
+			}
+		},
+	}
+}
+
+// SelectManyByIndexed projects each element of a collection to a Query, iterates and
+// flattens the resulting collection into one collection, and invokes
+// a result selector function on each element therein.
+// The index of each source element is used in the intermediate projected form
+// of that element.
+func (q Query) SelectManyByIndexed(selector func(int, interface{}) Query,
+	resultSelector func(interface{}, interface{}) interface{}) Query {
+
+	return Query{
+		Iterate: func() Iterator {
+			outernext := q.Iterate()
+			index := 0
+			var outer interface{}
+			var innernext Iterator
+
+			return func() (item interface{}, ok bool) {
+				for !ok {
+					if outer == nil {
+						outer, ok = outernext()
+						if !ok {
+							return
+						}
+
+						innernext = selector(index, outer).Iterate()
+						index++
+					}
+
+					item, ok = innernext()
+					if !ok {
+						outer = nil
+					}
+				}
+
+				item = resultSelector(outer, item)
+				return
+			}
+		},
+	}
+}