Added more test cases

main.go

@@ -38,7 +38,7 @@ func shuntingYard(re string) string {
 		re_postfix = append(re_postfix, re_runes[i])
 		if re_runes[i] != '(' && re_runes[i] != '|' {
 			if i < len(re_runes)-1 {
-				if re_runes[i+1] != '|' && re_runes[i+1] != '*' && re_runes[i+1] != ')' {
+				if re_runes[i+1] != '|' && re_runes[i+1] != '*' && re_runes[i+1] != '+' && re_runes[i+1] != ')' {
 					re_postfix = append(re_postfix, CONCAT)
 				}
 			}
@@ -139,7 +139,14 @@ func thompson(re string) *State {
 			stateToAdd.transitions[s1.content] = append(stateToAdd.transitions[s1.content], s1)
 			nfa = append(nfa, stateToAdd)
 		case '+':
-
+			s1 := pop(&nfa)
+			for i := range s1.output {
+				s1.output[i].transitions[s1.content] = append(s1.output[i].transitions[s1.content], s1)
+			}
+			// Reset output to s1 (in case s1 was a union operator state, which has multiple outputs)
+			s1.output = nil
+			s1.output = append(s1.output, s1)
+			nfa = append(nfa, s1)
 		case '|':
 			s1 := pop(&nfa)
 			s2 := pop(&nfa)

re_test.go

@@ -14,12 +14,19 @@ var reTests = []struct {
 	{"a", "bca", []matchIndex{{2, 3}}},
 	{"l", "ggllgg", []matchIndex{{2, 3}, {3, 4}}},
 	{"(b|c)", "abdceb", []matchIndex{{1, 2}, {3, 4}, {5, 6}}},
-	{"a*", "brerereraaaaabbbbb", []matchIndex{{8, 13}}},
+	{"a+", "brerereraaaaabbbbb", []matchIndex{{8, 13}}},
+	{"ab+", "qweqweqweaqweqweabbbbbr", []matchIndex{{16, 22}}},
+	{"(b|c|A)", "ooaoobocA", []matchIndex{{5, 6}, {7, 8}, {8, 9}}},
+	{"ab*", "a", []matchIndex{{0, 1}}},
+	{"ab*", "abb", []matchIndex{{0, 3}}},
+	{"(abc)*", "abcabcabc", []matchIndex{{0, 9}}},
+	{"((abc)|(def))*", "abcdef", []matchIndex{{0, 6}}},
+	{"(abc)*|(def)*", "abcdef", []matchIndex{{0, 3}, {3, 6}}},
 }
 
 func TestFindAllMatches(t *testing.T) {
 	for _, test := range reTests {
-		t.Run(test.re+" "+test.str, func(t *testing.T) {
+		t.Run(test.re+"	"+test.str, func(t *testing.T) {
 			re_postfix := shuntingYard(test.re)
 			startState := thompson(re_postfix)
 			matchIndices := findAllMatches(startState, test.str)