printer: initial implementation. I'm still experimenting though

printer/nodes.go

@@ -1 +1,84 @@
 package printer
+
+import (
+	"bytes"
+	"fmt"
+
+	"github.com/fatih/hcl/ast"
+)
+
+func (p *printer) printNode(n ast.Node) []byte {
+	var buf bytes.Buffer
+
+	switch t := n.(type) {
+	case *ast.ObjectList:
+		fmt.Println("printing objectList", t)
+		for _, item := range t.Items {
+			buf.Write(p.printObjectItem(item))
+		}
+	case *ast.ObjectKey:
+		fmt.Println("printing objectKey", t)
+	case *ast.ObjectItem:
+		fmt.Println("printing objectItem", t)
+		buf.Write(p.printObjectItem(t))
+	case *ast.LiteralType:
+		buf.Write(p.printLiteral(t))
+	case *ast.ListType:
+		buf.Write(p.printList(t))
+	case *ast.ObjectType:
+		fmt.Println("printing ObjectType", t)
+	default:
+		fmt.Printf(" unknown type: %T\n", n)
+	}
+
+	return buf.Bytes()
+}
+
+func (p *printer) printObjectItem(o *ast.ObjectItem) []byte {
+	var buf bytes.Buffer
+
+	for i, k := range o.Keys {
+		buf.WriteString(k.Token.Text)
+		if i != len(o.Keys)-1 || len(o.Keys) == 1 {
+			buf.WriteString(" ")
+		}
+
+		// reach end of key
+		if i == len(o.Keys)-1 {
+			buf.WriteString("=")
+			buf.WriteString(" ")
+		}
+	}
+
+	buf.Write(p.printNode(o.Val))
+	return buf.Bytes()
+}
+
+func (p *printer) printLiteral(l *ast.LiteralType) []byte {
+	return []byte(l.Token.Text)
+}
+
+func (p *printer) printList(l *ast.ListType) []byte {
+	var buf bytes.Buffer
+	buf.WriteString("[")
+
+	for i, item := range l.List {
+		if item.Pos().Line != l.Lbrack.Line {
+			// not same line
+			buf.WriteString("\n")
+		}
+
+		buf.Write(p.printNode(item))
+
+		if i != len(l.List)-1 {
+			buf.WriteString(",")
+			buf.WriteString(" ")
+		} else if item.Pos().Line != l.Lbrack.Line {
+			buf.WriteString(",")
+			buf.WriteString("\n")
+		}
+	}
+
+	buf.WriteString("]")
+	return buf.Bytes()
+}

printer/printer.go

@@ -1,7 +1,6 @@
 package printer
 
 import (
-	"bytes"
 	"fmt"
 	"io"
 	"text/tabwriter"
@@ -10,20 +9,14 @@ import (
 )
 
 type printer struct {
+	out  []byte // raw printer result
 	cfg  Config
 	node ast.Node
 }
 
 func (p *printer) output() []byte {
-	var buf bytes.Buffer
 	fmt.Println("STARTING OUTPUT")
-
-	ast.Walk(p.node, func(n ast.Node) bool {
-		fmt.Printf("n = %+v\n", n)
-		return true
-	})
-
-	return buf.Bytes()
+	return p.printNode(p.node)
 }
 
 // A Mode value is a set of flags (or 0). They control printing.
@@ -38,7 +31,7 @@ const (
 // A Config node controls the output of Fprint.
 type Config struct {
 	Mode     Mode // default: 0
-	Tabwidth int  // default: 8
+	Tabwidth int  // default: 4
 	Indent   int  // default: 0 (all code is indented at least by this much)
 }
 
@@ -94,5 +87,5 @@ func (c *Config) Fprint(output io.Writer, node ast.Node) error {
 // Fprint "pretty-prints" an HCL node to output
 // It calls Config.Fprint with default settings.
 func Fprint(output io.Writer, node ast.Node) error {
-	return (&Config{Tabwidth: 8}).Fprint(output, node)
+	return (&Config{Tabwidth: 4}).Fprint(output, node)
 }

printer/printer_test.go

@@ -7,6 +7,12 @@ import (
 	"github.com/fatih/hcl/parser"
 )
 
+var listHCL = `foo = ["fatih", "arslan"]`
+var listHCL2 = `foo = [
+		"fatih", 
+		"arslan",
+]`
+
 var complexHcl = `// This comes from Terraform, as a test
 variable "foo" {
     default = "bar"
@@ -52,7 +58,8 @@ output "web_ip" {
 `
 
 func TestPrint(t *testing.T) {
-	node, err := parser.Parse([]byte(complexHcl))
+	// node, err := parser.Parse([]byte(complexHcl))
+	node, err := parser.Parse([]byte(listHCL2))
 	if err != nil {
 		t.Fatal(err)
 	}