diff --git a/lexer/lexer.go b/lexer/lexer.go
new file mode 100644
index 0000000..26885ba
--- /dev/null
+++ b/lexer/lexer.go
@@ -0,0 +1,17 @@
+// Package lexer provides basic helpers to implement parsers
+package lexer
+
+// StateFn is a State Function of the parser
+type StateFn func() (StateFn, error)
+
+// Run runs a state machine until the state function either
+// returns nil or an error
+func Run(fn StateFn) error {
+	var err error
+
+	for fn != nil && err == nil {
+		fn, err = fn()
+	}
+
+	return err
+}