Add dot format ast exporter

Author: antonmedv

cmd/exp/dot.go

@@ -0,0 +1,190 @@
+package main
+
+import (
+	"fmt"
+	. "github.com/antonmedv/expr/ast"
+	"os"
+)
+
+const format = `digraph {
+	ranksep=.3;
+
+	node [shape=box, fixedsize=false, fontsize=12, fontname="Helvetica-bold", fontcolor="#1259FF", width=.25, height=.25, color="black", fillcolor="white", style="filled, solid, bold"];
+	edge [arrowsize=.5, color="black", style="bold"]
+
+%v
+%v}
+`
+
+func dotAst(node Node) {
+	v := &visitor{}
+	Walk(node, v)
+	dot := fmt.Sprintf(format, v.nodes, v.links)
+	_, _ = fmt.Fprintf(os.Stdout, dot)
+}
+
+type visitor struct {
+	nodes string
+	links string
+	index int
+	stack []int
+}
+
+func (v *visitor) push(label string) {
+	v.index++
+	v.nodes += fmt.Sprintf("	n%v [label=%q];\n", v.index, label)
+	v.stack = append(v.stack, v.index)
+}
+
+func (v *visitor) pop() int {
+	node := v.stack[len(v.stack)-1]
+	v.stack = v.stack[:len(v.stack)-1]
+	return node
+}
+
+func (v *visitor) link(node int) {
+	v.links += fmt.Sprintf("	n%v -> n%v\n", v.index, node)
+}
+
+func (v *visitor) NilNode(node *NilNode) {
+	v.push("nil")
+}
+
+func (v *visitor) IdentifierNode(node *IdentifierNode) {
+	v.push(node.Value)
+}
+
+func (v *visitor) IntegerNode(node *IntegerNode) {
+	v.push(fmt.Sprintf("%v", node.Value))
+}
+
+func (v *visitor) FloatNode(node *FloatNode) {
+	v.push(fmt.Sprintf("%v", node.Value))
+}
+
+func (v *visitor) BoolNode(node *BoolNode) {
+	v.push(fmt.Sprintf("%v", node.Value))
+}
+
+func (v *visitor) StringNode(node *StringNode) {
+	v.push(fmt.Sprintf("%q", node.Value))
+}
+
+func (v *visitor) UnaryNode(node *UnaryNode) {
+	n := v.pop()
+	v.push("-")
+	v.link(n)
+}
+
+func (v *visitor) BinaryNode(node *BinaryNode) {
+	b := v.pop()
+	a := v.pop()
+	v.push(node.Operator)
+	v.link(a)
+	v.link(b)
+}
+
+func (v *visitor) MatchesNode(node *MatchesNode) {
+	b := v.pop()
+	a := v.pop()
+	v.push("matches")
+	v.link(a)
+	v.link(b)
+}
+
+func (v *visitor) PropertyNode(node *PropertyNode) {
+	a := v.pop()
+	v.push(fmt.Sprintf(".%v", node.Property))
+	v.link(a)
+}
+
+func (v *visitor) IndexNode(node *IndexNode) {
+	b := v.pop()
+	a := v.pop()
+	v.push("[...]")
+	v.link(a)
+	v.link(b)
+}
+
+func (v *visitor) MethodNode(node *MethodNode) {
+	args := make([]int, 0)
+	for range node.Arguments {
+		args = append(args, v.pop())
+	}
+	a := v.pop()
+	v.push(fmt.Sprintf(".%v(...)", node.Method))
+	v.link(a)
+	for i := len(args) - 1; i >= 0; i-- {
+		v.link(args[i])
+	}
+}
+
+func (v *visitor) FunctionNode(node *FunctionNode) {
+	args := make([]int, 0)
+	for range node.Arguments {
+		args = append(args, v.pop())
+	}
+	v.push(fmt.Sprintf("%v(...)", node.Name))
+	for i := len(args) - 1; i >= 0; i-- {
+		v.link(args[i])
+	}
+}
+
+func (v *visitor) BuiltinNode(node *BuiltinNode) {
+	args := make([]int, 0)
+	for range node.Arguments {
+		args = append(args, v.pop())
+	}
+	v.push(fmt.Sprintf("%v(...)", node.Name))
+	for i := len(args) - 1; i >= 0; i-- {
+		v.link(args[i])
+	}
+}
+
+func (v *visitor) ClosureNode(node *ClosureNode) {
+	a := v.pop()
+	v.push("func {...}")
+	v.link(a)
+}
+
+func (v *visitor) PointerNode(node *PointerNode) {
+	v.push("#")
+}
+
+func (v *visitor) ConditionalNode(node *ConditionalNode) {
+	e2 := v.pop()
+	e1 := v.pop()
+	c := v.pop()
+	v.push("? :")
+	v.link(c)
+	v.link(e1)
+	v.link(e2)
+}
+
+func (v *visitor) ArrayNode(node *ArrayNode) {
+	n := make([]int, 0)
+	for range node.Nodes {
+		n = append(n, v.pop())
+	}
+	v.push("[...]")
+	for i := len(n) - 1; i >= 0; i-- {
+		v.link(n[i])
+	}
+}
+
+func (v *visitor) MapNode(node *MapNode) {
+	n := make([]int, 0)
+	for range node.Pairs {
+		n = append(n, v.pop())
+	}
+	v.push("{...}")
+	for i := len(n) - 1; i >= 0; i-- {
+		v.link(n[i])
+	}
+}
+
+func (v *visitor) PairNode(node *PairNode) {
+	a := v.pop()
+	v.push(fmt.Sprintf("%q:", node.Key.(*StringNode).Value))
+	v.link(a)
+}

cmd/exp/main.go

@@ -17,6 +17,7 @@ var (
 	debug    bool
 	run      bool
 	ast      bool
+	dot      bool
 	repl     bool
 )
 
@@ -25,6 +26,7 @@ func init() {
 	flag.BoolVar(&debug, "debug", false, "debug program")
 	flag.BoolVar(&run, "run", false, "run program")
 	flag.BoolVar(&ast, "ast", false, "print ast")
+	flag.BoolVar(&dot, "dot", false, "dot format")
 	flag.BoolVar(&repl, "repl", false, "start repl")
 }
 
@@ -74,7 +76,12 @@ func check(err error) {
 func printAst() {
 	tree, err := parser.Parse(input())
 	check(err)
-	litter.Dump(tree.Node)
+	if !dot {
+		litter.Dump(tree.Node)
+		return
+	}
+
+	dotAst(tree.Node)
 }
 
 func printDisassemble() {