parser: imrprovements to AST types

parser/ast.go

@@ -21,13 +21,16 @@ type Node interface {
 	Pos() scanner.Pos
 }
 
-func (Source) node()          {}
-func (Ident) node()           {}
-func (BlockStatement) node()  {}
+func (Source) node() {}
+func (Ident) node()  {}
+
 func (AssignStatement) node() {}
-func (ListStatement) node()   {}
 func (ObjectStatement) node() {}
 
+func (LiteralType) node() {}
+func (ObjectType) node()  {}
+func (ListType) node()    {}
+
 // Source represents a single HCL source file
 type Source struct {
 	nodes []Node
@@ -57,33 +60,13 @@ type Ident struct {
 }
 
 func (i *Ident) String() string {
-	return i.token.String()
+	return i.token.Text
 }
 
 func (i *Ident) Pos() scanner.Pos {
 	return i.token.Pos
 }
 
-type BlockStatement struct {
-	lbrace scanner.Pos // position of "{"
-	rbrace scanner.Pos // position of "}"
-	list   []Node      // the nodes in lexical order
-}
-
-func (b *BlockStatement) String() string {
-	s := "{\n"
-	for _, n := range b.list {
-		s += n.String() + "\n"
-	}
-
-	s += "}"
-	return s
-}
-
-func (b *BlockStatement) Pos() scanner.Pos {
-	return b.lbrace
-}
-
 // AssignStatement represents an assignment
 type AssignStatement struct {
 	lhs    Node        // left hand side of the assignment
@@ -99,31 +82,10 @@ func (a *AssignStatement) Pos() scanner.Pos {
 	return a.lhs.Pos()
 }
 
-// ListStatement represents a list
-type ListStatement struct {
-	lbrack scanner.Pos // position of "["
-	rbrack scanner.Pos // position of "]"
-	list   []Node      // the elements in lexical order
-}
-
-func (l *ListStatement) String() string {
-	s := "[\n"
-	for _, n := range l.list {
-		s += n.String() + ",\n"
-	}
-
-	s += "]"
-	return s
-}
-
-func (l *ListStatement) Pos() scanner.Pos {
-	return l.lbrack
-}
-
-// ObjectStatment represents an object
+// ObjectStatment represents an object statement
 type ObjectStatement struct {
 	Idents []Node // the idents in elements in lexical order
-	BlockStatement
+	ObjectType
 }
 
 func (o *ObjectStatement) String() string {
@@ -136,10 +98,66 @@ func (o *ObjectStatement) String() string {
 		}
 	}
 
-	s += o.BlockStatement.String()
+	s += o.ObjectType.String()
 	return s
 }
 
 func (o *ObjectStatement) Pos() scanner.Pos {
 	return o.Idents[0].Pos()
 }
+
+// LiteralType represents a literal of basic type. Valid types are:
+// scanner.NUMBER, scanner.FLOAT, scanner.BOOL and scanner.STRING
+type LiteralType struct {
+	token scanner.Token
+}
+
+func (l *LiteralType) String() string {
+	return l.token.Text
+}
+
+func (l *LiteralType) Pos() scanner.Pos {
+	return l.token.Pos
+}
+
+// ListStatement represents a HCL List type
+type ListType struct {
+	lbrack scanner.Pos // position of "["
+	rbrack scanner.Pos // position of "]"
+	list   []Node      // the elements in lexical order
+}
+
+func (l *ListType) String() string {
+	s := "[\n"
+	for _, n := range l.list {
+		s += n.String() + ",\n"
+	}
+
+	s += "]"
+	return s
+}
+
+func (l *ListType) Pos() scanner.Pos {
+	return l.lbrack
+}
+
+// ObjectType represents a HCL Object Type
+type ObjectType struct {
+	lbrace scanner.Pos // position of "{"
+	rbrace scanner.Pos // position of "}"
+	list   []Node      // the nodes in lexical order
+}
+
+func (b *ObjectType) String() string {
+	s := "{\n"
+	for _, n := range b.list {
+		s += n.String() + "\n"
+	}
+
+	s += "}"
+	return s
+}
+
+func (b *ObjectType) Pos() scanner.Pos {
+	return b.lbrace
+}

parser/parser.go

@@ -1,6 +1,7 @@
 package parser
 
 import (
+	"errors"
 	"fmt"
 
 	"github.com/fatih/hcl/scanner"
@@ -29,10 +30,13 @@ func (p *Parser) Parse() (Node, error) {
 	node := &Source{}
 
 	for {
-		if n := p.parseStatement(); n != nil {
-			node.add(n)
+		n, err := p.parseNode()
+		if err != nil {
+			return nil, err
 		}
 
+		node.add(n)
+
 		// break if we hit the end
 		if p.tok.Type == scanner.EOF {
 			break
@@ -42,17 +46,20 @@ func (p *Parser) Parse() (Node, error) {
 	return node, nil
 }
 
-func (p *Parser) parseStatement() Node {
-	defer un(trace(p, "ParseStatement"))
+func (p *Parser) parseNode() (Node, error) {
+	defer un(trace(p, "ParseNode"))
 
 	tok := p.scan()
 
+	fmt.Println(tok) // debug
+
 	if tok.Type.IsLiteral() {
 		if p.prevTok.Type.IsLiteral() {
-			return p.parseObject()
+			return p.parseObjectType()
 		}
 
-		if tok := p.scan(); tok.Type == scanner.ASSIGN {
+		tok := p.scan()
+		if tok.Type == scanner.ASSIGN {
 			return p.parseAssignment()
 		}
 
@@ -60,34 +67,45 @@ func (p *Parser) parseStatement() Node {
 		return p.parseIdent()
 	}
 
-	return nil
+	return nil, errors.New("not yet implemented")
 }
 
-func (p *Parser) parseAssignment() Node {
+func (p *Parser) parseAssignment() (*AssignStatement, error) {
 	defer un(trace(p, "ParseAssignment"))
-	return &AssignStatement{
+	a := &AssignStatement{
 		lhs: &Ident{
 			token: p.prevTok,
 		},
 		assign: p.tok.Pos,
-		rhs:    p.parseStatement(),
 	}
+
+	n, err := p.parseNode()
+	if err != nil {
+		return nil, err
+	}
+
+	a.rhs = n
+	return a, nil
 }
 
-func (p *Parser) parseIdent() Node {
+func (p *Parser) parseIdent() (*Ident, error) {
 	defer un(trace(p, "ParseIdent"))
 
+	if !p.tok.Type.IsLiteral() {
+		return nil, errors.New("can't parse non literal token")
+	}
+
 	return &Ident{
 		token: p.tok,
-	}
+	}, nil
 }
 
-func (p *Parser) parseObject() Node {
-	return nil
+func (p *Parser) parseObjectType() (*ObjectStatement, error) {
+	return nil, errors.New("ObjectStatement is not implemented yet")
 }
 
-func (p *Parser) parseList() Node {
-	return nil
+func (p *Parser) parseListType() (*ListType, error) {
+	return nil, errors.New("ListStatement is not implemented yet")
 }
 
 // scan returns the next token from the underlying scanner.

parser/parser_test.go

@@ -2,7 +2,7 @@ package parser
 
 import "testing"
 
-func TestAssignStatment(t *testing.T) {
+func TestAssignStatement(t *testing.T) {
 	src := `ami = "${var.foo}"`
 	p := New([]byte(src))
 	p.enableTrace = true

scanner/token.go

@@ -1,6 +1,9 @@
 package scanner
 
-import "strconv"
+import (
+	"fmt"
+	"strconv"
+)
 
 // Token defines a single HCL token which can be obtained via the Scanner
 type Token struct {
@@ -90,5 +93,5 @@ func (t TokenType) IsOperator() bool { return operator_beg < t && t < operator_e
 // applicable for certain token types, such as token.IDENT,
 // token.STRING, etc..
 func (t Token) String() string {
-	return t.Text
+	return fmt.Sprintf("%s %s %s", t.Pos.String(), t.Type.String(), t.Text)
 }