removes data races (fixes #3)

README.md

@@ -1359,6 +1359,10 @@ To run all test and all benchmarks:
 
     $ go test -bench . ./...
 
+To test with race detection:
+
+    $ go test -race ./...
+
 
 ## References
 

lexer/lexer.go

@@ -131,16 +131,6 @@ func (l *Lexer) NextToken() Token {
 	return result
 }
 
-// Pos returns the current byte position.
-func (l *Lexer) Pos() int {
-	return l.pos
-}
-
-// Line returns the current line number.
-func (l *Lexer) Line() int {
-	return l.line
-}
-
 // run starts lexical analysis
 func (l *Lexer) run() {
 	for l.nextFunc = lexContent; l.nextFunc != nil; {

parser/parser.go

@@ -104,7 +104,7 @@ func errExpected(expect lexer.TokenKind, tok *lexer.Token) {
 
 // program : statement*
 func (p *parser) parseProgram() *ast.Program {
-	result := ast.NewProgram(p.lex.Pos(), p.lex.Line())
+	result := ast.NewProgram(p.next().Pos, p.next().Line)
 
 	for p.isStatement() {
 		result.AddStatement(p.parseStatement())
@@ -368,7 +368,7 @@ func (p *parser) parseInverseChain() *ast.Program {
 		return p.parseInverseAndProgram()
 	}
 
-	result := ast.NewProgram(p.lex.Pos(), p.lex.Line())
+	result := ast.NewProgram(p.next().Pos, p.next().Line)
 
 	// openInverseChain
 	block, blockParams := p.parseOpenBlock()