do not include files already parsed

fixes #4

example/example.cfg

@@ -9,7 +9,7 @@ primary {
   negative = FALSE;
   nothing = NULL;
   # Include external files
-  include "./include*.cfg";
+  include "./*.cfg";
   # Primary-sub stuff
   sub {
       key = "primary sub key value";

forge.go

@@ -101,7 +101,6 @@ package forge
 import (
 	"bytes"
 	"io"
-	"os"
 	"strings"
 )
 
@@ -116,11 +115,16 @@ func ParseBytes(data []byte) (*Section, error) {
 // and responds with `*Section` and potentially an `error` if it cannot
 // properly parse the configf
 func ParseFile(filename string) (*Section, error) {
-	reader, err := os.Open(filename)
+	parser, err := NewFileParser(filename)
 	if err != nil {
 		return nil, err
 	}
-	return ParseReader(reader)
+	err = parser.Parse()
+	if err != nil {
+		return nil, err
+	}
+
+	return parser.GetSettings(), nil
 }
 
 // ParseReader takes an `io.Reader` representation of the config file, parses it

parser.go

@@ -13,6 +13,7 @@ import (
 
 // Parser is a struct to hold data necessary for parsing a config from a scanner
 type Parser struct {
+	files      []string
 	settings   *Section
 	scanner    *Scanner
 	curTok     token.Token
@@ -24,6 +25,7 @@ type Parser struct {
 func NewParser(reader io.Reader) *Parser {
 	settings := NewSection()
 	return &Parser{
+		files:      make([]string, 0),
 		scanner:    NewScanner(reader),
 		settings:   settings,
 		curSection: settings,
@@ -31,6 +33,30 @@ func NewParser(reader io.Reader) *Parser {
 	}
 }
 
+// NewParser will create and initialize a new Parser from a provided from a filename string
+func NewFileParser(filename string) (*Parser, error) {
+	reader, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	parser := NewParser(reader)
+	parser.addFile(filename)
+	return parser, nil
+}
+
+func (parser *Parser) addFile(filename string) {
+	parser.files = append(parser.files, filename)
+}
+
+func (parser *Parser) hasParsed(search string) bool {
+	for _, filename := range parser.files {
+		if filename == search {
+			return true
+		}
+	}
+	return false
+}
+
 func (parser *Parser) syntaxError(msg string) error {
 	msg = fmt.Sprintf(
 		"syntax error line <%d> column <%d>: %s",
@@ -165,6 +191,11 @@ func (parser *Parser) parseInclude() error {
 	}
 	oldScanner := parser.scanner
 	for _, filename := range filenames {
+		// We have already visited this file, don't include again
+		// DEV: This can cause recursive includes if this isn't here :o
+		if parser.hasParsed(filename) {
+			continue
+		}
 		reader, err := os.Open(filename)
 		if err != nil {
 			return err
@@ -172,6 +203,9 @@ func (parser *Parser) parseInclude() error {
 		parser.curSection.AddInclude(filename)
 		parser.scanner = NewScanner(reader)
 		parser.parse()
+		// Make sure to add the filename to the internal list to ensure we don't
+		// accidentally recursively include config files
+		parser.addFile(filename)
 	}
 	parser.scanner = oldScanner
 	parser.readToken()