Added new assertion that always evaluates to true

nfa.go

@@ -18,6 +18,7 @@ const (
 	NLA         // Negative lookahead
 	PLB         // Positive lookbehind
 	NLB         // Negative lookbehind
+	ALWAYS_TRUE // An assertion that is always true
 )
 
 type State struct {
@@ -103,6 +104,9 @@ func cloneStateHelper(state *State, cloneMap map[*State]*State) *State {
 // Checks if the given state's assertion is true. Returns true if the given
 // state doesn't have an assertion.
 func (s State) checkAssertion(str []rune, idx int) bool {
+	if s.assert == ALWAYS_TRUE {
+		return true
+	}
 	if s.assert == SOS {
 		return idx == 0
 	}