Initial commit:

Added framework to generate DOT and png files of character map chart
from data folder.
Added all figures in the 1-2 chapters.
Added font file SimSum for render chart

pkg/relationship/relationship.go

@@ -0,0 +1,24 @@
+package relationship
+
+import "fmt"
+
+type Relationship struct {
+	Src         string `yaml:"source"`
+	Dst         string `yaml:"destination"`
+	Description string `yaml:"description"`
+	Bidirection bool   `yaml:"bidirection"`
+}
+
+func (r Relationship) IsSame(other Relationship) bool {
+	if r.Bidirection {
+		if r.Description != other.Description {
+			return false
+		}
+		return (r.Src == other.Src && r.Dst == other.Dst) || (r.Src == other.Dst && r.Dst == other.Src)
+	}
+	return r.Src == other.Src && r.Dst == other.Dst && r.Description == other.Description
+}
+
+func (r Relationship) GetKey() (string, string) {
+	return fmt.Sprintf("%s-%s", r.Src, r.Dst), fmt.Sprintf("%s-%s", r.Dst, r.Src)
+}