bake: initial implementation

Signed-off-by: Tonis Tiigi <tonistiigi@gmail.com>

vendor/github.com/hashicorp/hcl/hcl/ast/ast.go

@@ -0,0 +1,219 @@
+// Package ast declares the types used to represent syntax trees for HCL
+// (HashiCorp Configuration Language)
+package ast
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/hcl/hcl/token"
+)
+
+// Node is an element in the abstract syntax tree.
+type Node interface {
+	node()
+	Pos() token.Pos
+}
+
+func (File) node()         {}
+func (ObjectList) node()   {}
+func (ObjectKey) node()    {}
+func (ObjectItem) node()   {}
+func (Comment) node()      {}
+func (CommentGroup) node() {}
+func (ObjectType) node()   {}
+func (LiteralType) node()  {}
+func (ListType) node()     {}
+
+// File represents a single HCL file
+type File struct {
+	Node     Node            // usually a *ObjectList
+	Comments []*CommentGroup // list of all comments in the source
+}
+
+func (f *File) Pos() token.Pos {
+	return f.Node.Pos()
+}
+
+// ObjectList represents a list of ObjectItems. An HCL file itself is an
+// ObjectList.
+type ObjectList struct {
+	Items []*ObjectItem
+}
+
+func (o *ObjectList) Add(item *ObjectItem) {
+	o.Items = append(o.Items, item)
+}
+
+// Filter filters out the objects with the given key list as a prefix.
+//
+// The returned list of objects contain ObjectItems where the keys have
+// this prefix already stripped off. This might result in objects with
+// zero-length key lists if they have no children.
+//
+// If no matches are found, an empty ObjectList (non-nil) is returned.
+func (o *ObjectList) Filter(keys ...string) *ObjectList {
+	var result ObjectList
+	for _, item := range o.Items {
+		// If there aren't enough keys, then ignore this
+		if len(item.Keys) < len(keys) {
+			continue
+		}
+
+		match := true
+		for i, key := range item.Keys[:len(keys)] {
+			key := key.Token.Value().(string)
+			if key != keys[i] && !strings.EqualFold(key, keys[i]) {
+				match = false
+				break
+			}
+		}
+		if !match {
+			continue
+		}
+
+		// Strip off the prefix from the children
+		newItem := *item
+		newItem.Keys = newItem.Keys[len(keys):]
+		result.Add(&newItem)
+	}
+
+	return &result
+}
+
+// Children returns further nested objects (key length > 0) within this
+// ObjectList. This should be used with Filter to get at child items.
+func (o *ObjectList) Children() *ObjectList {
+	var result ObjectList
+	for _, item := range o.Items {
+		if len(item.Keys) > 0 {
+			result.Add(item)
+		}
+	}
+
+	return &result
+}
+
+// Elem returns items in the list that are direct element assignments
+// (key length == 0). This should be used with Filter to get at elements.
+func (o *ObjectList) Elem() *ObjectList {
+	var result ObjectList
+	for _, item := range o.Items {
+		if len(item.Keys) == 0 {
+			result.Add(item)
+		}
+	}
+
+	return &result
+}
+
+func (o *ObjectList) Pos() token.Pos {
+	// always returns the uninitiliazed position
+	return o.Items[0].Pos()
+}
+
+// ObjectItem represents a HCL Object Item. An item is represented with a key
+// (or keys). It can be an assignment or an object (both normal and nested)
+type ObjectItem struct {
+	// keys is only one length long if it's of type assignment. If it's a
+	// nested object it can be larger than one. In that case "assign" is
+	// invalid as there is no assignments for a nested object.
+	Keys []*ObjectKey
+
+	// assign contains the position of "=", if any
+	Assign token.Pos
+
+	// val is the item itself. It can be an object,list, number, bool or a
+	// string. If key length is larger than one, val can be only of type
+	// Object.
+	Val Node
+
+	LeadComment *CommentGroup // associated lead comment
+	LineComment *CommentGroup // associated line comment
+}
+
+func (o *ObjectItem) Pos() token.Pos {
+	// I'm not entirely sure what causes this, but removing this causes
+	// a test failure. We should investigate at some point.
+	if len(o.Keys) == 0 {
+		return token.Pos{}
+	}
+
+	return o.Keys[0].Pos()
+}
+
+// ObjectKeys are either an identifier or of type string.
+type ObjectKey struct {
+	Token token.Token
+}
+
+func (o *ObjectKey) Pos() token.Pos {
+	return o.Token.Pos
+}
+
+// LiteralType represents a literal of basic type. Valid types are:
+// token.NUMBER, token.FLOAT, token.BOOL and token.STRING
+type LiteralType struct {
+	Token token.Token
+
+	// comment types, only used when in a list
+	LeadComment *CommentGroup
+	LineComment *CommentGroup
+}
+
+func (l *LiteralType) Pos() token.Pos {
+	return l.Token.Pos
+}
+
+// ListStatement represents a HCL List type
+type ListType struct {
+	Lbrack token.Pos // position of "["
+	Rbrack token.Pos // position of "]"
+	List   []Node    // the elements in lexical order
+}
+
+func (l *ListType) Pos() token.Pos {
+	return l.Lbrack
+}
+
+func (l *ListType) Add(node Node) {
+	l.List = append(l.List, node)
+}
+
+// ObjectType represents a HCL Object Type
+type ObjectType struct {
+	Lbrace token.Pos   // position of "{"
+	Rbrace token.Pos   // position of "}"
+	List   *ObjectList // the nodes in lexical order
+}
+
+func (o *ObjectType) Pos() token.Pos {
+	return o.Lbrace
+}
+
+// Comment node represents a single //, # style or /*- style commment
+type Comment struct {
+	Start token.Pos // position of / or #
+	Text  string
+}
+
+func (c *Comment) Pos() token.Pos {
+	return c.Start
+}
+
+// CommentGroup node represents a sequence of comments with no other tokens and
+// no empty lines between.
+type CommentGroup struct {
+	List []*Comment // len(List) > 0
+}
+
+func (c *CommentGroup) Pos() token.Pos {
+	return c.List[0].Pos()
+}
+
+//-------------------------------------------------------------------
+// GoStringer
+//-------------------------------------------------------------------
+
+func (o *ObjectKey) GoString() string  { return fmt.Sprintf("*%#v", *o) }
+func (o *ObjectList) GoString() string { return fmt.Sprintf("*%#v", *o) }

vendor/github.com/hashicorp/hcl/hcl/ast/walk.go

@@ -0,0 +1,52 @@
+package ast
+
+import "fmt"
+
+// WalkFunc describes a function to be called for each node during a Walk. The
+// returned node can be used to rewrite the AST. Walking stops the returned
+// bool is false.
+type WalkFunc func(Node) (Node, bool)
+
+// Walk traverses an AST in depth-first order: It starts by calling fn(node);
+// node must not be nil. If fn returns true, Walk invokes fn recursively for
+// each of the non-nil children of node, followed by a call of fn(nil). The
+// returned node of fn can be used to rewrite the passed node to fn.
+func Walk(node Node, fn WalkFunc) Node {
+	rewritten, ok := fn(node)
+	if !ok {
+		return rewritten
+	}
+
+	switch n := node.(type) {
+	case *File:
+		n.Node = Walk(n.Node, fn)
+	case *ObjectList:
+		for i, item := range n.Items {
+			n.Items[i] = Walk(item, fn).(*ObjectItem)
+		}
+	case *ObjectKey:
+		// nothing to do
+	case *ObjectItem:
+		for i, k := range n.Keys {
+			n.Keys[i] = Walk(k, fn).(*ObjectKey)
+		}
+
+		if n.Val != nil {
+			n.Val = Walk(n.Val, fn)
+		}
+	case *LiteralType:
+		// nothing to do
+	case *ListType:
+		for i, l := range n.List {
+			n.List[i] = Walk(l, fn)
+		}
+	case *ObjectType:
+		n.List = Walk(n.List, fn).(*ObjectList)
+	default:
+		// should we panic here?
+		fmt.Printf("unknown type: %T\n", n)
+	}
+
+	fn(nil)
+	return rewritten
+}

vendor/github.com/hashicorp/hcl/hcl/parser/error.go

@@ -0,0 +1,17 @@
+package parser
+
+import (
+	"fmt"
+
+	"github.com/hashicorp/hcl/hcl/token"
+)
+
+// PosError is a parse error that contains a position.
+type PosError struct {
+	Pos token.Pos
+	Err error
+}
+
+func (e *PosError) Error() string {
+	return fmt.Sprintf("At %s: %s", e.Pos, e.Err)
+}

vendor/github.com/hashicorp/hcl/hcl/parser/parser.go

@@ -0,0 +1,532 @@
+// Package parser implements a parser for HCL (HashiCorp Configuration
+// Language)
+package parser
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/hcl/hcl/ast"
+	"github.com/hashicorp/hcl/hcl/scanner"
+	"github.com/hashicorp/hcl/hcl/token"
+)
+
+type Parser struct {
+	sc *scanner.Scanner
+
+	// Last read token
+	tok       token.Token
+	commaPrev token.Token
+
+	comments    []*ast.CommentGroup
+	leadComment *ast.CommentGroup // last lead comment
+	lineComment *ast.CommentGroup // last line comment
+
+	enableTrace bool
+	indent      int
+	n           int // buffer size (max = 1)
+}
+
+func newParser(src []byte) *Parser {
+	return &Parser{
+		sc: scanner.New(src),
+	}
+}
+
+// Parse returns the fully parsed source and returns the abstract syntax tree.
+func Parse(src []byte) (*ast.File, error) {
+	// normalize all line endings
+	// since the scanner and output only work with "\n" line endings, we may
+	// end up with dangling "\r" characters in the parsed data.
+	src = bytes.Replace(src, []byte("\r\n"), []byte("\n"), -1)
+
+	p := newParser(src)
+	return p.Parse()
+}
+
+var errEofToken = errors.New("EOF token found")
+
+// Parse returns the fully parsed source and returns the abstract syntax tree.
+func (p *Parser) Parse() (*ast.File, error) {
+	f := &ast.File{}
+	var err, scerr error
+	p.sc.Error = func(pos token.Pos, msg string) {
+		scerr = &PosError{Pos: pos, Err: errors.New(msg)}
+	}
+
+	f.Node, err = p.objectList(false)
+	if scerr != nil {
+		return nil, scerr
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	f.Comments = p.comments
+	return f, nil
+}
+
+// objectList parses a list of items within an object (generally k/v pairs).
+// The parameter" obj" tells this whether to we are within an object (braces:
+// '{', '}') or just at the top level. If we're within an object, we end
+// at an RBRACE.
+func (p *Parser) objectList(obj bool) (*ast.ObjectList, error) {
+	defer un(trace(p, "ParseObjectList"))
+	node := &ast.ObjectList{}
+
+	for {
+		if obj {
+			tok := p.scan()
+			p.unscan()
+			if tok.Type == token.RBRACE {
+				break
+			}
+		}
+
+		n, err := p.objectItem()
+		if err == errEofToken {
+			break // we are finished
+		}
+
+		// we don't return a nil node, because might want to use already
+		// collected items.
+		if err != nil {
+			return node, err
+		}
+
+		node.Add(n)
+
+		// object lists can be optionally comma-delimited e.g. when a list of maps
+		// is being expressed, so a comma is allowed here - it's simply consumed
+		tok := p.scan()
+		if tok.Type != token.COMMA {
+			p.unscan()
+		}
+	}
+	return node, nil
+}
+
+func (p *Parser) consumeComment() (comment *ast.Comment, endline int) {
+	endline = p.tok.Pos.Line
+
+	// count the endline if it's multiline comment, ie starting with /*
+	if len(p.tok.Text) > 1 && p.tok.Text[1] == '*' {
+		// don't use range here - no need to decode Unicode code points
+		for i := 0; i < len(p.tok.Text); i++ {
+			if p.tok.Text[i] == '\n' {
+				endline++
+			}
+		}
+	}
+
+	comment = &ast.Comment{Start: p.tok.Pos, Text: p.tok.Text}
+	p.tok = p.sc.Scan()
+	return
+}
+
+func (p *Parser) consumeCommentGroup(n int) (comments *ast.CommentGroup, endline int) {
+	var list []*ast.Comment
+	endline = p.tok.Pos.Line
+
+	for p.tok.Type == token.COMMENT && p.tok.Pos.Line <= endline+n {
+		var comment *ast.Comment
+		comment, endline = p.consumeComment()
+		list = append(list, comment)
+	}
+
+	// add comment group to the comments list
+	comments = &ast.CommentGroup{List: list}
+	p.comments = append(p.comments, comments)
+
+	return
+}
+
+// objectItem parses a single object item
+func (p *Parser) objectItem() (*ast.ObjectItem, error) {
+	defer un(trace(p, "ParseObjectItem"))
+
+	keys, err := p.objectKey()
+	if len(keys) > 0 && err == errEofToken {
+		// We ignore eof token here since it is an error if we didn't
+		// receive a value (but we did receive a key) for the item.
+		err = nil
+	}
+	if len(keys) > 0 && err != nil && p.tok.Type == token.RBRACE {
+		// This is a strange boolean statement, but what it means is:
+		// We have keys with no value, and we're likely in an object
+		// (since RBrace ends an object). For this, we set err to nil so
+		// we continue and get the error below of having the wrong value
+		// type.
+		err = nil
+
+		// Reset the token type so we don't think it completed fine. See
+		// objectType which uses p.tok.Type to check if we're done with
+		// the object.
+		p.tok.Type = token.EOF
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	o := &ast.ObjectItem{
+		Keys: keys,
+	}
+
+	if p.leadComment != nil {
+		o.LeadComment = p.leadComment
+		p.leadComment = nil
+	}
+
+	switch p.tok.Type {
+	case token.ASSIGN:
+		o.Assign = p.tok.Pos
+		o.Val, err = p.object()
+		if err != nil {
+			return nil, err
+		}
+	case token.LBRACE:
+		o.Val, err = p.objectType()
+		if err != nil {
+			return nil, err
+		}
+	default:
+		keyStr := make([]string, 0, len(keys))
+		for _, k := range keys {
+			keyStr = append(keyStr, k.Token.Text)
+		}
+
+		return nil, &PosError{
+			Pos: p.tok.Pos,
+			Err: fmt.Errorf(
+				"key '%s' expected start of object ('{') or assignment ('=')",
+				strings.Join(keyStr, " ")),
+		}
+	}
+
+	// key=#comment
+	// val
+	if p.lineComment != nil {
+		o.LineComment, p.lineComment = p.lineComment, nil
+	}
+
+	// do a look-ahead for line comment
+	p.scan()
+	if len(keys) > 0 && o.Val.Pos().Line == keys[0].Pos().Line && p.lineComment != nil {
+		o.LineComment = p.lineComment
+		p.lineComment = nil
+	}
+	p.unscan()
+	return o, nil
+}
+
+// objectKey parses an object key and returns a ObjectKey AST
+func (p *Parser) objectKey() ([]*ast.ObjectKey, error) {
+	keyCount := 0
+	keys := make([]*ast.ObjectKey, 0)
+
+	for {
+		tok := p.scan()
+		switch tok.Type {
+		case token.EOF:
+			// It is very important to also return the keys here as well as
+			// the error. This is because we need to be able to tell if we
+			// did parse keys prior to finding the EOF, or if we just found
+			// a bare EOF.
+			return keys, errEofToken
+		case token.ASSIGN:
+			// assignment or object only, but not nested objects. this is not
+			// allowed: `foo bar = {}`
+			if keyCount > 1 {
+				return nil, &PosError{
+					Pos: p.tok.Pos,
+					Err: fmt.Errorf("nested object expected: LBRACE got: %s", p.tok.Type),
+				}
+			}
+
+			if keyCount == 0 {
+				return nil, &PosError{
+					Pos: p.tok.Pos,
+					Err: errors.New("no object keys found!"),
+				}
+			}
+
+			return keys, nil
+		case token.LBRACE:
+			var err error
+
+			// If we have no keys, then it is a syntax error. i.e. {{}} is not
+			// allowed.
+			if len(keys) == 0 {
+				err = &PosError{
+					Pos: p.tok.Pos,
+					Err: fmt.Errorf("expected: IDENT | STRING got: %s", p.tok.Type),
+				}
+			}
+
+			// object
+			return keys, err
+		case token.IDENT, token.STRING:
+			keyCount++
+			keys = append(keys, &ast.ObjectKey{Token: p.tok})
+		case token.ILLEGAL:
+			return keys, &PosError{
+				Pos: p.tok.Pos,
+				Err: fmt.Errorf("illegal character"),
+			}
+		default:
+			return keys, &PosError{
+				Pos: p.tok.Pos,
+				Err: fmt.Errorf("expected: IDENT | STRING | ASSIGN | LBRACE got: %s", p.tok.Type),
+			}
+		}
+	}
+}
+
+// object parses any type of object, such as number, bool, string, object or
+// list.
+func (p *Parser) object() (ast.Node, error) {
+	defer un(trace(p, "ParseType"))
+	tok := p.scan()
+
+	switch tok.Type {
+	case token.NUMBER, token.FLOAT, token.BOOL, token.STRING, token.HEREDOC:
+		return p.literalType()
+	case token.LBRACE:
+		return p.objectType()
+	case token.LBRACK:
+		return p.listType()
+	case token.COMMENT:
+		// implement comment
+	case token.EOF:
+		return nil, errEofToken
+	}
+
+	return nil, &PosError{
+		Pos: tok.Pos,
+		Err: fmt.Errorf("Unknown token: %+v", tok),
+	}
+}
+
+// objectType parses an object type and returns a ObjectType AST
+func (p *Parser) objectType() (*ast.ObjectType, error) {
+	defer un(trace(p, "ParseObjectType"))
+
+	// we assume that the currently scanned token is a LBRACE
+	o := &ast.ObjectType{
+		Lbrace: p.tok.Pos,
+	}
+
+	l, err := p.objectList(true)
+
+	// if we hit RBRACE, we are good to go (means we parsed all Items), if it's
+	// not a RBRACE, it's an syntax error and we just return it.
+	if err != nil && p.tok.Type != token.RBRACE {
+		return nil, err
+	}
+
+	// No error, scan and expect the ending to be a brace
+	if tok := p.scan(); tok.Type != token.RBRACE {
+		return nil, &PosError{
+			Pos: tok.Pos,
+			Err: fmt.Errorf("object expected closing RBRACE got: %s", tok.Type),
+		}
+	}
+
+	o.List = l
+	o.Rbrace = p.tok.Pos // advanced via parseObjectList
+	return o, nil
+}
+
+// listType parses a list type and returns a ListType AST
+func (p *Parser) listType() (*ast.ListType, error) {
+	defer un(trace(p, "ParseListType"))
+
+	// we assume that the currently scanned token is a LBRACK
+	l := &ast.ListType{
+		Lbrack: p.tok.Pos,
+	}
+
+	needComma := false
+	for {
+		tok := p.scan()
+		if needComma {
+			switch tok.Type {
+			case token.COMMA, token.RBRACK:
+			default:
+				return nil, &PosError{
+					Pos: tok.Pos,
+					Err: fmt.Errorf(
+						"error parsing list, expected comma or list end, got: %s",
+						tok.Type),
+				}
+			}
+		}
+		switch tok.Type {
+		case token.BOOL, token.NUMBER, token.FLOAT, token.STRING, token.HEREDOC:
+			node, err := p.literalType()
+			if err != nil {
+				return nil, err
+			}
+
+			// If there is a lead comment, apply it
+			if p.leadComment != nil {
+				node.LeadComment = p.leadComment
+				p.leadComment = nil
+			}
+
+			l.Add(node)
+			needComma = true
+		case token.COMMA:
+			// get next list item or we are at the end
+			// do a look-ahead for line comment
+			p.scan()
+			if p.lineComment != nil && len(l.List) > 0 {
+				lit, ok := l.List[len(l.List)-1].(*ast.LiteralType)
+				if ok {
+					lit.LineComment = p.lineComment
+					l.List[len(l.List)-1] = lit
+					p.lineComment = nil
+				}
+			}
+			p.unscan()
+
+			needComma = false
+			continue
+		case token.LBRACE:
+			// Looks like a nested object, so parse it out
+			node, err := p.objectType()
+			if err != nil {
+				return nil, &PosError{
+					Pos: tok.Pos,
+					Err: fmt.Errorf(
+						"error while trying to parse object within list: %s", err),
+				}
+			}
+			l.Add(node)
+			needComma = true
+		case token.LBRACK:
+			node, err := p.listType()
+			if err != nil {
+				return nil, &PosError{
+					Pos: tok.Pos,
+					Err: fmt.Errorf(
+						"error while trying to parse list within list: %s", err),
+				}
+			}
+			l.Add(node)
+		case token.RBRACK:
+			// finished
+			l.Rbrack = p.tok.Pos
+			return l, nil
+		default:
+			return nil, &PosError{
+				Pos: tok.Pos,
+				Err: fmt.Errorf("unexpected token while parsing list: %s", tok.Type),
+			}
+		}
+	}
+}
+
+// literalType parses a literal type and returns a LiteralType AST
+func (p *Parser) literalType() (*ast.LiteralType, error) {
+	defer un(trace(p, "ParseLiteral"))
+
+	return &ast.LiteralType{
+		Token: p.tok,
+	}, nil
+}
+
+// scan returns the next token from the underlying scanner. If a token has
+// been unscanned then read that instead. In the process, it collects any
+// comment groups encountered, and remembers the last lead and line comments.
+func (p *Parser) scan() token.Token {
+	// If we have a token on the buffer, then return it.
+	if p.n != 0 {
+		p.n = 0
+		return p.tok
+	}
+
+	// Otherwise read the next token from the scanner and Save it to the buffer
+	// in case we unscan later.
+	prev := p.tok
+	p.tok = p.sc.Scan()
+
+	if p.tok.Type == token.COMMENT {
+		var comment *ast.CommentGroup
+		var endline int
+
+		// fmt.Printf("p.tok.Pos.Line = %+v prev: %d endline %d \n",
+		// p.tok.Pos.Line, prev.Pos.Line, endline)
+		if p.tok.Pos.Line == prev.Pos.Line {
+			// The comment is on same line as the previous token; it
+			// cannot be a lead comment but may be a line comment.
+			comment, endline = p.consumeCommentGroup(0)
+			if p.tok.Pos.Line != endline {
+				// The next token is on a different line, thus
+				// the last comment group is a line comment.
+				p.lineComment = comment
+			}
+		}
+
+		// consume successor comments, if any
+		endline = -1
+		for p.tok.Type == token.COMMENT {
+			comment, endline = p.consumeCommentGroup(1)
+		}
+
+		if endline+1 == p.tok.Pos.Line && p.tok.Type != token.RBRACE {
+			switch p.tok.Type {
+			case token.RBRACE, token.RBRACK:
+				// Do not count for these cases
+			default:
+				// The next token is following on the line immediately after the
+				// comment group, thus the last comment group is a lead comment.
+				p.leadComment = comment
+			}
+		}
+
+	}
+
+	return p.tok
+}
+
+// unscan pushes the previously read token back onto the buffer.
+func (p *Parser) unscan() {
+	p.n = 1
+}
+
+// ----------------------------------------------------------------------------
+// Parsing support
+
+func (p *Parser) printTrace(a ...interface{}) {
+	if !p.enableTrace {
+		return
+	}
+
+	const dots = ". . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . "
+	const n = len(dots)
+	fmt.Printf("%5d:%3d: ", p.tok.Pos.Line, p.tok.Pos.Column)
+
+	i := 2 * p.indent
+	for i > n {
+		fmt.Print(dots)
+		i -= n
+	}
+	// i <= n
+	fmt.Print(dots[0:i])
+	fmt.Println(a...)
+}
+
+func trace(p *Parser, msg string) *Parser {
+	p.printTrace(msg, "(")
+	p.indent++
+	return p
+}
+
+// Usage pattern: defer un(trace(p, "..."))
+func un(p *Parser) {
+	p.indent--
+	p.printTrace(")")
+}

vendor/github.com/hashicorp/hcl/hcl/scanner/scanner.go

@@ -0,0 +1,652 @@
+// Package scanner implements a scanner for HCL (HashiCorp Configuration
+// Language) source text.
+package scanner
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"regexp"
+	"unicode"
+	"unicode/utf8"
+
+	"github.com/hashicorp/hcl/hcl/token"
+)
+
+// eof represents a marker rune for the end of the reader.
+const eof = rune(0)
+
+// Scanner defines a lexical scanner
+type Scanner struct {
+	buf *bytes.Buffer // Source buffer for advancing and scanning
+	src []byte        // Source buffer for immutable access
+
+	// Source Position
+	srcPos  token.Pos // current position
+	prevPos token.Pos // previous position, used for peek() method
+
+	lastCharLen int // length of last character in bytes
+	lastLineLen int // length of last line in characters (for correct column reporting)
+
+	tokStart int // token text start position
+	tokEnd   int // token text end  position
+
+	// Error is called for each error encountered. If no Error
+	// function is set, the error is reported to os.Stderr.
+	Error func(pos token.Pos, msg string)
+
+	// ErrorCount is incremented by one for each error encountered.
+	ErrorCount int
+
+	// tokPos is the start position of most recently scanned token; set by
+	// Scan. The Filename field is always left untouched by the Scanner.  If
+	// an error is reported (via Error) and Position is invalid, the scanner is
+	// not inside a token.
+	tokPos token.Pos
+}
+
+// New creates and initializes a new instance of Scanner using src as
+// its source content.
+func New(src []byte) *Scanner {
+	// even though we accept a src, we read from a io.Reader compatible type
+	// (*bytes.Buffer). So in the future we might easily change it to streaming
+	// read.
+	b := bytes.NewBuffer(src)
+	s := &Scanner{
+		buf: b,
+		src: src,
+	}
+
+	// srcPosition always starts with 1
+	s.srcPos.Line = 1
+	return s
+}
+
+// next reads the next rune from the bufferred reader. Returns the rune(0) if
+// an error occurs (or io.EOF is returned).
+func (s *Scanner) next() rune {
+	ch, size, err := s.buf.ReadRune()
+	if err != nil {
+		// advance for error reporting
+		s.srcPos.Column++
+		s.srcPos.Offset += size
+		s.lastCharLen = size
+		return eof
+	}
+
+	// remember last position
+	s.prevPos = s.srcPos
+
+	s.srcPos.Column++
+	s.lastCharLen = size
+	s.srcPos.Offset += size
+
+	if ch == utf8.RuneError && size == 1 {
+		s.err("illegal UTF-8 encoding")
+		return ch
+	}
+
+	if ch == '\n' {
+		s.srcPos.Line++
+		s.lastLineLen = s.srcPos.Column
+		s.srcPos.Column = 0
+	}
+
+	if ch == '\x00' {
+		s.err("unexpected null character (0x00)")
+		return eof
+	}
+
+	if ch == '\uE123' {
+		s.err("unicode code point U+E123 reserved for internal use")
+		return utf8.RuneError
+	}
+
+	// debug
+	// fmt.Printf("ch: %q, offset:column: %d:%d\n", ch, s.srcPos.Offset, s.srcPos.Column)
+	return ch
+}
+
+// unread unreads the previous read Rune and updates the source position
+func (s *Scanner) unread() {
+	if err := s.buf.UnreadRune(); err != nil {
+		panic(err) // this is user fault, we should catch it
+	}
+	s.srcPos = s.prevPos // put back last position
+}
+
+// peek returns the next rune without advancing the reader.
+func (s *Scanner) peek() rune {
+	peek, _, err := s.buf.ReadRune()
+	if err != nil {
+		return eof
+	}
+
+	s.buf.UnreadRune()
+	return peek
+}
+
+// Scan scans the next token and returns the token.
+func (s *Scanner) Scan() token.Token {
+	ch := s.next()
+
+	// skip white space
+	for isWhitespace(ch) {
+		ch = s.next()
+	}
+
+	var tok token.Type
+
+	// token text markings
+	s.tokStart = s.srcPos.Offset - s.lastCharLen
+
+	// token position, initial next() is moving the offset by one(size of rune
+	// actually), though we are interested with the starting point
+	s.tokPos.Offset = s.srcPos.Offset - s.lastCharLen
+	if s.srcPos.Column > 0 {
+		// common case: last character was not a '\n'
+		s.tokPos.Line = s.srcPos.Line
+		s.tokPos.Column = s.srcPos.Column
+	} else {
+		// last character was a '\n'
+		// (we cannot be at the beginning of the source
+		// since we have called next() at least once)
+		s.tokPos.Line = s.srcPos.Line - 1
+		s.tokPos.Column = s.lastLineLen
+	}
+
+	switch {
+	case isLetter(ch):
+		tok = token.IDENT
+		lit := s.scanIdentifier()
+		if lit == "true" || lit == "false" {
+			tok = token.BOOL
+		}
+	case isDecimal(ch):
+		tok = s.scanNumber(ch)
+	default:
+		switch ch {
+		case eof:
+			tok = token.EOF
+		case '"':
+			tok = token.STRING
+			s.scanString()
+		case '#', '/':
+			tok = token.COMMENT
+			s.scanComment(ch)
+		case '.':
+			tok = token.PERIOD
+			ch = s.peek()
+			if isDecimal(ch) {
+				tok = token.FLOAT
+				ch = s.scanMantissa(ch)
+				ch = s.scanExponent(ch)
+			}
+		case '<':
+			tok = token.HEREDOC
+			s.scanHeredoc()
+		case '[':
+			tok = token.LBRACK
+		case ']':
+			tok = token.RBRACK
+		case '{':
+			tok = token.LBRACE
+		case '}':
+			tok = token.RBRACE
+		case ',':
+			tok = token.COMMA
+		case '=':
+			tok = token.ASSIGN
+		case '+':
+			tok = token.ADD
+		case '-':
+			if isDecimal(s.peek()) {
+				ch := s.next()
+				tok = s.scanNumber(ch)
+			} else {
+				tok = token.SUB
+			}
+		default:
+			s.err("illegal char")
+		}
+	}
+
+	// finish token ending
+	s.tokEnd = s.srcPos.Offset
+
+	// create token literal
+	var tokenText string
+	if s.tokStart >= 0 {
+		tokenText = string(s.src[s.tokStart:s.tokEnd])
+	}
+	s.tokStart = s.tokEnd // ensure idempotency of tokenText() call
+
+	return token.Token{
+		Type: tok,
+		Pos:  s.tokPos,
+		Text: tokenText,
+	}
+}
+
+func (s *Scanner) scanComment(ch rune) {
+	// single line comments
+	if ch == '#' || (ch == '/' && s.peek() != '*') {
+		if ch == '/' && s.peek() != '/' {
+			s.err("expected '/' for comment")
+			return
+		}
+
+		ch = s.next()
+		for ch != '\n' && ch >= 0 && ch != eof {
+			ch = s.next()
+		}
+		if ch != eof && ch >= 0 {
+			s.unread()
+		}
+		return
+	}
+
+	// be sure we get the character after /* This allows us to find comment's
+	// that are not erminated
+	if ch == '/' {
+		s.next()
+		ch = s.next() // read character after "/*"
+	}
+
+	// look for /* - style comments
+	for {
+		if ch < 0 || ch == eof {
+			s.err("comment not terminated")
+			break
+		}
+
+		ch0 := ch
+		ch = s.next()
+		if ch0 == '*' && ch == '/' {
+			break
+		}
+	}
+}
+
+// scanNumber scans a HCL number definition starting with the given rune
+func (s *Scanner) scanNumber(ch rune) token.Type {
+	if ch == '0' {
+		// check for hexadecimal, octal or float
+		ch = s.next()
+		if ch == 'x' || ch == 'X' {
+			// hexadecimal
+			ch = s.next()
+			found := false
+			for isHexadecimal(ch) {
+				ch = s.next()
+				found = true
+			}
+
+			if !found {
+				s.err("illegal hexadecimal number")
+			}
+
+			if ch != eof {
+				s.unread()
+			}
+
+			return token.NUMBER
+		}
+
+		// now it's either something like: 0421(octal) or 0.1231(float)
+		illegalOctal := false
+		for isDecimal(ch) {
+			ch = s.next()
+			if ch == '8' || ch == '9' {
+				// this is just a possibility. For example 0159 is illegal, but
+				// 0159.23 is valid. So we mark a possible illegal octal. If
+				// the next character is not a period, we'll print the error.
+				illegalOctal = true
+			}
+		}
+
+		if ch == 'e' || ch == 'E' {
+			ch = s.scanExponent(ch)
+			return token.FLOAT
+		}
+
+		if ch == '.' {
+			ch = s.scanFraction(ch)
+
+			if ch == 'e' || ch == 'E' {
+				ch = s.next()
+				ch = s.scanExponent(ch)
+			}
+			return token.FLOAT
+		}
+
+		if illegalOctal {
+			s.err("illegal octal number")
+		}
+
+		if ch != eof {
+			s.unread()
+		}
+		return token.NUMBER
+	}
+
+	s.scanMantissa(ch)
+	ch = s.next() // seek forward
+	if ch == 'e' || ch == 'E' {
+		ch = s.scanExponent(ch)
+		return token.FLOAT
+	}
+
+	if ch == '.' {
+		ch = s.scanFraction(ch)
+		if ch == 'e' || ch == 'E' {
+			ch = s.next()
+			ch = s.scanExponent(ch)
+		}
+		return token.FLOAT
+	}
+
+	if ch != eof {
+		s.unread()
+	}
+	return token.NUMBER
+}
+
+// scanMantissa scans the mantissa beginning from the rune. It returns the next
+// non decimal rune. It's used to determine wheter it's a fraction or exponent.
+func (s *Scanner) scanMantissa(ch rune) rune {
+	scanned := false
+	for isDecimal(ch) {
+		ch = s.next()
+		scanned = true
+	}
+
+	if scanned && ch != eof {
+		s.unread()
+	}
+	return ch
+}
+
+// scanFraction scans the fraction after the '.' rune
+func (s *Scanner) scanFraction(ch rune) rune {
+	if ch == '.' {
+		ch = s.peek() // we peek just to see if we can move forward
+		ch = s.scanMantissa(ch)
+	}
+	return ch
+}
+
+// scanExponent scans the remaining parts of an exponent after the 'e' or 'E'
+// rune.
+func (s *Scanner) scanExponent(ch rune) rune {
+	if ch == 'e' || ch == 'E' {
+		ch = s.next()
+		if ch == '-' || ch == '+' {
+			ch = s.next()
+		}
+		ch = s.scanMantissa(ch)
+	}
+	return ch
+}
+
+// scanHeredoc scans a heredoc string
+func (s *Scanner) scanHeredoc() {
+	// Scan the second '<' in example: '<<EOF'
+	if s.next() != '<' {
+		s.err("heredoc expected second '<', didn't see it")
+		return
+	}
+
+	// Get the original offset so we can read just the heredoc ident
+	offs := s.srcPos.Offset
+
+	// Scan the identifier
+	ch := s.next()
+
+	// Indented heredoc syntax
+	if ch == '-' {
+		ch = s.next()
+	}
+
+	for isLetter(ch) || isDigit(ch) {
+		ch = s.next()
+	}
+
+	// If we reached an EOF then that is not good
+	if ch == eof {
+		s.err("heredoc not terminated")
+		return
+	}
+
+	// Ignore the '\r' in Windows line endings
+	if ch == '\r' {
+		if s.peek() == '\n' {
+			ch = s.next()
+		}
+	}
+
+	// If we didn't reach a newline then that is also not good
+	if ch != '\n' {
+		s.err("invalid characters in heredoc anchor")
+		return
+	}
+
+	// Read the identifier
+	identBytes := s.src[offs : s.srcPos.Offset-s.lastCharLen]
+	if len(identBytes) == 0 || (len(identBytes) == 1 && identBytes[0] == '-') {
+		s.err("zero-length heredoc anchor")
+		return
+	}
+
+	var identRegexp *regexp.Regexp
+	if identBytes[0] == '-' {
+		identRegexp = regexp.MustCompile(fmt.Sprintf(`^[[:space:]]*%s\r*\z`, identBytes[1:]))
+	} else {
+		identRegexp = regexp.MustCompile(fmt.Sprintf(`^[[:space:]]*%s\r*\z`, identBytes))
+	}
+
+	// Read the actual string value
+	lineStart := s.srcPos.Offset
+	for {
+		ch := s.next()
+
+		// Special newline handling.
+		if ch == '\n' {
+			// Math is fast, so we first compare the byte counts to see if we have a chance
+			// of seeing the same identifier - if the length is less than the number of bytes
+			// in the identifier, this cannot be a valid terminator.
+			lineBytesLen := s.srcPos.Offset - s.lastCharLen - lineStart
+			if lineBytesLen >= len(identBytes) && identRegexp.Match(s.src[lineStart:s.srcPos.Offset-s.lastCharLen]) {
+				break
+			}
+
+			// Not an anchor match, record the start of a new line
+			lineStart = s.srcPos.Offset
+		}
+
+		if ch == eof {
+			s.err("heredoc not terminated")
+			return
+		}
+	}
+
+	return
+}
+
+// scanString scans a quoted string
+func (s *Scanner) scanString() {
+	braces := 0
+	for {
+		// '"' opening already consumed
+		// read character after quote
+		ch := s.next()
+
+		if (ch == '\n' && braces == 0) || ch < 0 || ch == eof {
+			s.err("literal not terminated")
+			return
+		}
+
+		if ch == '"' && braces == 0 {
+			break
+		}
+
+		// If we're going into a ${} then we can ignore quotes for awhile
+		if braces == 0 && ch == '$' && s.peek() == '{' {
+			braces++
+			s.next()
+		} else if braces > 0 && ch == '{' {
+			braces++
+		}
+		if braces > 0 && ch == '}' {
+			braces--
+		}
+
+		if ch == '\\' {
+			s.scanEscape()
+		}
+	}
+
+	return
+}
+
+// scanEscape scans an escape sequence
+func (s *Scanner) scanEscape() rune {
+	// http://en.cppreference.com/w/cpp/language/escape
+	ch := s.next() // read character after '/'
+	switch ch {
+	case 'a', 'b', 'f', 'n', 'r', 't', 'v', '\\', '"':
+		// nothing to do
+	case '0', '1', '2', '3', '4', '5', '6', '7':
+		// octal notation
+		ch = s.scanDigits(ch, 8, 3)
+	case 'x':
+		// hexademical notation
+		ch = s.scanDigits(s.next(), 16, 2)
+	case 'u':
+		// universal character name
+		ch = s.scanDigits(s.next(), 16, 4)
+	case 'U':
+		// universal character name
+		ch = s.scanDigits(s.next(), 16, 8)
+	default:
+		s.err("illegal char escape")
+	}
+	return ch
+}
+
+// scanDigits scans a rune with the given base for n times. For example an
+// octal notation \184 would yield in scanDigits(ch, 8, 3)
+func (s *Scanner) scanDigits(ch rune, base, n int) rune {
+	start := n
+	for n > 0 && digitVal(ch) < base {
+		ch = s.next()
+		if ch == eof {
+			// If we see an EOF, we halt any more scanning of digits
+			// immediately.
+			break
+		}
+
+		n--
+	}
+	if n > 0 {
+		s.err("illegal char escape")
+	}
+
+	if n != start && ch != eof {
+		// we scanned all digits, put the last non digit char back,
+		// only if we read anything at all
+		s.unread()
+	}
+
+	return ch
+}
+
+// scanIdentifier scans an identifier and returns the literal string
+func (s *Scanner) scanIdentifier() string {
+	offs := s.srcPos.Offset - s.lastCharLen
+	ch := s.next()
+	for isLetter(ch) || isDigit(ch) || ch == '-' || ch == '.' {
+		ch = s.next()
+	}
+
+	if ch != eof {
+		s.unread() // we got identifier, put back latest char
+	}
+
+	return string(s.src[offs:s.srcPos.Offset])
+}
+
+// recentPosition returns the position of the character immediately after the
+// character or token returned by the last call to Scan.
+func (s *Scanner) recentPosition() (pos token.Pos) {
+	pos.Offset = s.srcPos.Offset - s.lastCharLen
+	switch {
+	case s.srcPos.Column > 0:
+		// common case: last character was not a '\n'
+		pos.Line = s.srcPos.Line
+		pos.Column = s.srcPos.Column
+	case s.lastLineLen > 0:
+		// last character was a '\n'
+		// (we cannot be at the beginning of the source
+		// since we have called next() at least once)
+		pos.Line = s.srcPos.Line - 1
+		pos.Column = s.lastLineLen
+	default:
+		// at the beginning of the source
+		pos.Line = 1
+		pos.Column = 1
+	}
+	return
+}
+
+// err prints the error of any scanning to s.Error function. If the function is
+// not defined, by default it prints them to os.Stderr
+func (s *Scanner) err(msg string) {
+	s.ErrorCount++
+	pos := s.recentPosition()
+
+	if s.Error != nil {
+		s.Error(pos, msg)
+		return
+	}
+
+	fmt.Fprintf(os.Stderr, "%s: %s\n", pos, msg)
+}
+
+// isHexadecimal returns true if the given rune is a letter
+func isLetter(ch rune) bool {
+	return 'a' <= ch && ch <= 'z' || 'A' <= ch && ch <= 'Z' || ch == '_' || ch >= 0x80 && unicode.IsLetter(ch)
+}
+
+// isDigit returns true if the given rune is a decimal digit
+func isDigit(ch rune) bool {
+	return '0' <= ch && ch <= '9' || ch >= 0x80 && unicode.IsDigit(ch)
+}
+
+// isDecimal returns true if the given rune is a decimal number
+func isDecimal(ch rune) bool {
+	return '0' <= ch && ch <= '9'
+}
+
+// isHexadecimal returns true if the given rune is an hexadecimal number
+func isHexadecimal(ch rune) bool {
+	return '0' <= ch && ch <= '9' || 'a' <= ch && ch <= 'f' || 'A' <= ch && ch <= 'F'
+}
+
+// isWhitespace returns true if the rune is a space, tab, newline or carriage return
+func isWhitespace(ch rune) bool {
+	return ch == ' ' || ch == '\t' || ch == '\n' || ch == '\r'
+}
+
+// digitVal returns the integer value of a given octal,decimal or hexadecimal rune
+func digitVal(ch rune) int {
+	switch {
+	case '0' <= ch && ch <= '9':
+		return int(ch - '0')
+	case 'a' <= ch && ch <= 'f':
+		return int(ch - 'a' + 10)
+	case 'A' <= ch && ch <= 'F':
+		return int(ch - 'A' + 10)
+	}
+	return 16 // larger than any legal digit val
+}

vendor/github.com/hashicorp/hcl/hcl/strconv/quote.go

@@ -0,0 +1,241 @@
+package strconv
+
+import (
+	"errors"
+	"unicode/utf8"
+)
+
+// ErrSyntax indicates that a value does not have the right syntax for the target type.
+var ErrSyntax = errors.New("invalid syntax")
+
+// Unquote interprets s as a single-quoted, double-quoted,
+// or backquoted Go string literal, returning the string value
+// that s quotes.  (If s is single-quoted, it would be a Go
+// character literal; Unquote returns the corresponding
+// one-character string.)
+func Unquote(s string) (t string, err error) {
+	n := len(s)
+	if n < 2 {
+		return "", ErrSyntax
+	}
+	quote := s[0]
+	if quote != s[n-1] {
+		return "", ErrSyntax
+	}
+	s = s[1 : n-1]
+
+	if quote != '"' {
+		return "", ErrSyntax
+	}
+	if !contains(s, '$') && !contains(s, '{') && contains(s, '\n') {
+		return "", ErrSyntax
+	}
+
+	// Is it trivial?  Avoid allocation.
+	if !contains(s, '\\') && !contains(s, quote) && !contains(s, '$') {
+		switch quote {
+		case '"':
+			return s, nil
+		case '\'':
+			r, size := utf8.DecodeRuneInString(s)
+			if size == len(s) && (r != utf8.RuneError || size != 1) {
+				return s, nil
+			}
+		}
+	}
+
+	var runeTmp [utf8.UTFMax]byte
+	buf := make([]byte, 0, 3*len(s)/2) // Try to avoid more allocations.
+	for len(s) > 0 {
+		// If we're starting a '${}' then let it through un-unquoted.
+		// Specifically: we don't unquote any characters within the `${}`
+		// section.
+		if s[0] == '$' && len(s) > 1 && s[1] == '{' {
+			buf = append(buf, '$', '{')
+			s = s[2:]
+
+			// Continue reading until we find the closing brace, copying as-is
+			braces := 1
+			for len(s) > 0 && braces > 0 {
+				r, size := utf8.DecodeRuneInString(s)
+				if r == utf8.RuneError {
+					return "", ErrSyntax
+				}
+
+				s = s[size:]
+
+				n := utf8.EncodeRune(runeTmp[:], r)
+				buf = append(buf, runeTmp[:n]...)
+
+				switch r {
+				case '{':
+					braces++
+				case '}':
+					braces--
+				}
+			}
+			if braces != 0 {
+				return "", ErrSyntax
+			}
+			if len(s) == 0 {
+				// If there's no string left, we're done!
+				break
+			} else {
+				// If there's more left, we need to pop back up to the top of the loop
+				// in case there's another interpolation in this string.
+				continue
+			}
+		}
+
+		if s[0] == '\n' {
+			return "", ErrSyntax
+		}
+
+		c, multibyte, ss, err := unquoteChar(s, quote)
+		if err != nil {
+			return "", err
+		}
+		s = ss
+		if c < utf8.RuneSelf || !multibyte {
+			buf = append(buf, byte(c))
+		} else {
+			n := utf8.EncodeRune(runeTmp[:], c)
+			buf = append(buf, runeTmp[:n]...)
+		}
+		if quote == '\'' && len(s) != 0 {
+			// single-quoted must be single character
+			return "", ErrSyntax
+		}
+	}
+	return string(buf), nil
+}
+
+// contains reports whether the string contains the byte c.
+func contains(s string, c byte) bool {
+	for i := 0; i < len(s); i++ {
+		if s[i] == c {
+			return true
+		}
+	}
+	return false
+}
+
+func unhex(b byte) (v rune, ok bool) {
+	c := rune(b)
+	switch {
+	case '0' <= c && c <= '9':
+		return c - '0', true
+	case 'a' <= c && c <= 'f':
+		return c - 'a' + 10, true
+	case 'A' <= c && c <= 'F':
+		return c - 'A' + 10, true
+	}
+	return
+}
+
+func unquoteChar(s string, quote byte) (value rune, multibyte bool, tail string, err error) {
+	// easy cases
+	switch c := s[0]; {
+	case c == quote && (quote == '\'' || quote == '"'):
+		err = ErrSyntax
+		return
+	case c >= utf8.RuneSelf:
+		r, size := utf8.DecodeRuneInString(s)
+		return r, true, s[size:], nil
+	case c != '\\':
+		return rune(s[0]), false, s[1:], nil
+	}
+
+	// hard case: c is backslash
+	if len(s) <= 1 {
+		err = ErrSyntax
+		return
+	}
+	c := s[1]
+	s = s[2:]
+
+	switch c {
+	case 'a':
+		value = '\a'
+	case 'b':
+		value = '\b'
+	case 'f':
+		value = '\f'
+	case 'n':
+		value = '\n'
+	case 'r':
+		value = '\r'
+	case 't':
+		value = '\t'
+	case 'v':
+		value = '\v'
+	case 'x', 'u', 'U':
+		n := 0
+		switch c {
+		case 'x':
+			n = 2
+		case 'u':
+			n = 4
+		case 'U':
+			n = 8
+		}
+		var v rune
+		if len(s) < n {
+			err = ErrSyntax
+			return
+		}
+		for j := 0; j < n; j++ {
+			x, ok := unhex(s[j])
+			if !ok {
+				err = ErrSyntax
+				return
+			}
+			v = v<<4 | x
+		}
+		s = s[n:]
+		if c == 'x' {
+			// single-byte string, possibly not UTF-8
+			value = v
+			break
+		}
+		if v > utf8.MaxRune {
+			err = ErrSyntax
+			return
+		}
+		value = v
+		multibyte = true
+	case '0', '1', '2', '3', '4', '5', '6', '7':
+		v := rune(c) - '0'
+		if len(s) < 2 {
+			err = ErrSyntax
+			return
+		}
+		for j := 0; j < 2; j++ { // one digit already; two more
+			x := rune(s[j]) - '0'
+			if x < 0 || x > 7 {
+				err = ErrSyntax
+				return
+			}
+			v = (v << 3) | x
+		}
+		s = s[2:]
+		if v > 255 {
+			err = ErrSyntax
+			return
+		}
+		value = v
+	case '\\':
+		value = '\\'
+	case '\'', '"':
+		if c != quote {
+			err = ErrSyntax
+			return
+		}
+		value = rune(c)
+	default:
+		err = ErrSyntax
+		return
+	}
+	tail = s
+	return
+}

vendor/github.com/hashicorp/hcl/hcl/token/position.go

@@ -0,0 +1,46 @@
+package token
+
+import "fmt"
+
+// Pos describes an arbitrary source position
+// including the file, line, and column location.
+// A Position is valid if the line number is > 0.
+type Pos struct {
+	Filename string // filename, if any
+	Offset   int    // offset, starting at 0
+	Line     int    // line number, starting at 1
+	Column   int    // column number, starting at 1 (character count)
+}
+
+// IsValid returns true if the position is valid.
+func (p *Pos) IsValid() bool { return p.Line > 0 }
+
+// String returns a string in one of several forms:
+//
+//	file:line:column    valid position with file name
+//	line:column         valid position without file name
+//	file                invalid position with file name
+//	-                   invalid position without file name
+func (p Pos) String() string {
+	s := p.Filename
+	if p.IsValid() {
+		if s != "" {
+			s += ":"
+		}
+		s += fmt.Sprintf("%d:%d", p.Line, p.Column)
+	}
+	if s == "" {
+		s = "-"
+	}
+	return s
+}
+
+// Before reports whether the position p is before u.
+func (p Pos) Before(u Pos) bool {
+	return u.Offset > p.Offset || u.Line > p.Line
+}
+
+// After reports whether the position p is after u.
+func (p Pos) After(u Pos) bool {
+	return u.Offset < p.Offset || u.Line < p.Line
+}

vendor/github.com/hashicorp/hcl/hcl/token/token.go

@@ -0,0 +1,219 @@
+// Package token defines constants representing the lexical tokens for HCL
+// (HashiCorp Configuration Language)
+package token
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	hclstrconv "github.com/hashicorp/hcl/hcl/strconv"
+)
+
+// Token defines a single HCL token which can be obtained via the Scanner
+type Token struct {
+	Type Type
+	Pos  Pos
+	Text string
+	JSON bool
+}
+
+// Type is the set of lexical tokens of the HCL (HashiCorp Configuration Language)
+type Type int
+
+const (
+	// Special tokens
+	ILLEGAL Type = iota
+	EOF
+	COMMENT
+
+	identifier_beg
+	IDENT // literals
+	literal_beg
+	NUMBER  // 12345
+	FLOAT   // 123.45
+	BOOL    // true,false
+	STRING  // "abc"
+	HEREDOC // <<FOO\nbar\nFOO
+	literal_end
+	identifier_end
+
+	operator_beg
+	LBRACK // [
+	LBRACE // {
+	COMMA  // ,
+	PERIOD // .
+
+	RBRACK // ]
+	RBRACE // }
+
+	ASSIGN // =
+	ADD    // +
+	SUB    // -
+	operator_end
+)
+
+var tokens = [...]string{
+	ILLEGAL: "ILLEGAL",
+
+	EOF:     "EOF",
+	COMMENT: "COMMENT",
+
+	IDENT:  "IDENT",
+	NUMBER: "NUMBER",
+	FLOAT:  "FLOAT",
+	BOOL:   "BOOL",
+	STRING: "STRING",
+
+	LBRACK:  "LBRACK",
+	LBRACE:  "LBRACE",
+	COMMA:   "COMMA",
+	PERIOD:  "PERIOD",
+	HEREDOC: "HEREDOC",
+
+	RBRACK: "RBRACK",
+	RBRACE: "RBRACE",
+
+	ASSIGN: "ASSIGN",
+	ADD:    "ADD",
+	SUB:    "SUB",
+}
+
+// String returns the string corresponding to the token tok.
+func (t Type) String() string {
+	s := ""
+	if 0 <= t && t < Type(len(tokens)) {
+		s = tokens[t]
+	}
+	if s == "" {
+		s = "token(" + strconv.Itoa(int(t)) + ")"
+	}
+	return s
+}
+
+// IsIdentifier returns true for tokens corresponding to identifiers and basic
+// type literals; it returns false otherwise.
+func (t Type) IsIdentifier() bool { return identifier_beg < t && t < identifier_end }
+
+// IsLiteral returns true for tokens corresponding to basic type literals; it
+// returns false otherwise.
+func (t Type) IsLiteral() bool { return literal_beg < t && t < literal_end }
+
+// IsOperator returns true for tokens corresponding to operators and
+// delimiters; it returns false otherwise.
+func (t Type) IsOperator() bool { return operator_beg < t && t < operator_end }
+
+// String returns the token's literal text. Note that this is only
+// applicable for certain token types, such as token.IDENT,
+// token.STRING, etc..
+func (t Token) String() string {
+	return fmt.Sprintf("%s %s %s", t.Pos.String(), t.Type.String(), t.Text)
+}
+
+// Value returns the properly typed value for this token. The type of
+// the returned interface{} is guaranteed based on the Type field.
+//
+// This can only be called for literal types. If it is called for any other
+// type, this will panic.
+func (t Token) Value() interface{} {
+	switch t.Type {
+	case BOOL:
+		if t.Text == "true" {
+			return true
+		} else if t.Text == "false" {
+			return false
+		}
+
+		panic("unknown bool value: " + t.Text)
+	case FLOAT:
+		v, err := strconv.ParseFloat(t.Text, 64)
+		if err != nil {
+			panic(err)
+		}
+
+		return float64(v)
+	case NUMBER:
+		v, err := strconv.ParseInt(t.Text, 0, 64)
+		if err != nil {
+			panic(err)
+		}
+
+		return int64(v)
+	case IDENT:
+		return t.Text
+	case HEREDOC:
+		return unindentHeredoc(t.Text)
+	case STRING:
+		// Determine the Unquote method to use. If it came from JSON,
+		// then we need to use the built-in unquote since we have to
+		// escape interpolations there.
+		f := hclstrconv.Unquote
+		if t.JSON {
+			f = strconv.Unquote
+		}
+
+		// This case occurs if json null is used
+		if t.Text == "" {
+			return ""
+		}
+
+		v, err := f(t.Text)
+		if err != nil {
+			panic(fmt.Sprintf("unquote %s err: %s", t.Text, err))
+		}
+
+		return v
+	default:
+		panic(fmt.Sprintf("unimplemented Value for type: %s", t.Type))
+	}
+}
+
+// unindentHeredoc returns the string content of a HEREDOC if it is started with <<
+// and the content of a HEREDOC with the hanging indent removed if it is started with
+// a <<-, and the terminating line is at least as indented as the least indented line.
+func unindentHeredoc(heredoc string) string {
+	// We need to find the end of the marker
+	idx := strings.IndexByte(heredoc, '\n')
+	if idx == -1 {
+		panic("heredoc doesn't contain newline")
+	}
+
+	unindent := heredoc[2] == '-'
+
+	// We can optimize if the heredoc isn't marked for indentation
+	if !unindent {
+		return string(heredoc[idx+1 : len(heredoc)-idx+1])
+	}
+
+	// We need to unindent each line based on the indentation level of the marker
+	lines := strings.Split(string(heredoc[idx+1:len(heredoc)-idx+2]), "\n")
+	whitespacePrefix := lines[len(lines)-1]
+
+	isIndented := true
+	for _, v := range lines {
+		if strings.HasPrefix(v, whitespacePrefix) {
+			continue
+		}
+
+		isIndented = false
+		break
+	}
+
+	// If all lines are not at least as indented as the terminating mark, return the
+	// heredoc as is, but trim the leading space from the marker on the final line.
+	if !isIndented {
+		return strings.TrimRight(string(heredoc[idx+1:len(heredoc)-idx+1]), " \t")
+	}
+
+	unindentedLines := make([]string, len(lines))
+	for k, v := range lines {
+		if k == len(lines)-1 {
+			unindentedLines[k] = ""
+			break
+		}
+
+		unindentedLines[k] = strings.TrimPrefix(v, whitespacePrefix)
+	}
+
+	return strings.Join(unindentedLines, "\n")
+}