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package digraph
import (
"fmt"
"strings"
)
// BasicNode is a digraph Node that has a name and out edges
type BasicNode struct {
Name string
NodeEdges []Edge
}
func (b *BasicNode) Edges() []Edge {
return b.NodeEdges
}
func (b *BasicNode) AddEdge(edge Edge) {
b.NodeEdges = append(b.NodeEdges, edge)
}
func (b *BasicNode) String() string {
if b.Name == "" {
return "Node"
}
return fmt.Sprintf("%v", b.Name)
}
// BasicEdge is a digraph Edge that has a name, head and tail
type BasicEdge struct {
Name string
EdgeHead *BasicNode
EdgeTail *BasicNode
}
func (b *BasicEdge) Head() Node {
return b.EdgeHead
}
// Tail returns the end point of the Edge
func (b *BasicEdge) Tail() Node {
return b.EdgeTail
}
func (b *BasicEdge) String() string {
if b.Name == "" {
return "Edge"
}
return fmt.Sprintf("%v", b.Name)
}
// ParseBasic is used to parse a string in the format of:
// a -> b ; edge name
// b -> c
// Into a series of basic node and basic edges
func ParseBasic(s string) map[string]*BasicNode {
lines := strings.Split(s, "\n")
nodes := make(map[string]*BasicNode)
for _, line := range lines {
var edgeName string
if idx := strings.Index(line, ";"); idx >= 0 {
edgeName = strings.Trim(line[idx+1:], " \t\r\n")
line = line[:idx]
}
parts := strings.SplitN(line, "->", 2)
if len(parts) != 2 {
continue
}
head_name := strings.Trim(parts[0], " \t\r\n")
tail_name := strings.Trim(parts[1], " \t\r\n")
head := nodes[head_name]
if head == nil {
head = &BasicNode{Name: head_name}
nodes[head_name] = head
}
tail := nodes[tail_name]
if tail == nil {
tail = &BasicNode{Name: tail_name}
nodes[tail_name] = tail
}
edge := &BasicEdge{
Name: edgeName,
EdgeHead: head,
EdgeTail: tail,
}
head.AddEdge(edge)
}
return nodes
}
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