add fleunt interface

README.md

@@ -102,6 +102,7 @@ A curated collection of idiomatic design & application patterns for Go language.
 | Pattern | Description | Status |
 |:-------:|:----------- |:------:|
 | [Functional Options](/idiom/functional-options.md) | Allows creating clean APIs with sane defaults and idiomatic overrides | ✔ |
+| [Fluent interface](/idiom/fluent-interace.md) | Method for constructing object oriented APIs focused on better readability | ✔ |
 
 ## Anti-Patterns
 

idiom/fluent-interface.md

@@ -0,0 +1,77 @@
+# Fluent interface
+
+Fluent interface is a method for constructing object oriented APIs
+focused on better readability. Implemented by using method chaining
+
+## Implementation
+
+```go
+package fluent
+
+type Align int
+
+const (
+	Left = iota
+	Center = iota
+	Right = iota
+)
+
+type TextContainer struct {
+    Font string
+    FontSize int
+    Color string
+    Align Align
+}
+
+func NewTextContainer() *TextContainer {
+    return &TextContainer{
+        Font: "Helvetica",
+        FontSize: 10,
+        Color: "Red",
+        Align: Left}
+}
+
+func (tc *TextContainer) SetFont (font string) *TextContainer {
+    tc.Font = font
+    return tc
+}
+
+func (tc *TextContainer) SetFontSize (fontSize int) *TextContainer {
+    tc.FontSize = fontSize
+    return tc
+}
+
+func (tc *TextContainer) SetColor (color string) *TextContainer {
+    tc.Color = color
+    return tc
+}
+
+func (tc *TextContainer) SetAlign (align Align) *TextContainer {
+    tc.Align = align
+    return tc
+}
+```
+
+## Usage
+```go
+func getAlignText(align Align) string{
+    switch align{
+        case Left:
+            return "Left"
+        case Center:
+            return "Center"
+        case Right:
+            return "Right"
+        default:
+            panic("Not determinated align")
+    }
+}
+
+tContainer := NewTextContainer()
+tContainer.SetFont("Calibri").SetFontSize(20).SetColor("Green").SetAlign(Center)
+
+fmt.Printf("Font: %s\n", tContainer.Font)
+fmt.Printf("Font size: %v\n", tContainer.FontSize)
+fmt.Printf("Color: %s\n", tContainer.Color)
+fmt.Printf("Align: %s\n", getAlignText(tContainer.Align))
+```