//go:generate re2go $INPUT -o $OUTPUT package main import "testing" // Returns "fake" terminating null if cursor has reached limit. func peek(str string, cursor int, limit int) byte { if cursor >= limit { return 0 // fake null } else { return str[cursor] } } // Expects a string without terminating null. func lex(str string) int { var cursor, marker int limit := len(str) count := 0 loop: /*!re2c re2c:yyfill:enable = 0; re2c:eof = 0; re2c:define:YYCTYPE = byte; re2c:define:YYLESSTHAN = "cursor >= limit"; re2c:define:YYPEEK = "peek(str, cursor, limit)"; re2c:define:YYSKIP = "cursor += 1"; re2c:define:YYBACKUP = "marker = cursor"; re2c:define:YYRESTORE = "cursor = marker"; * { return -1 } $ { return count } ['] ([^'\\] | [\\][^])* ['] { count += 1; goto loop } [ ]+ { goto loop } */ } func TestLex(t *testing.T) { var tests = []struct { res int str string }{ {0, ""}, {3, "'qu\000tes' 'are' 'fine: \\'' "}, {-1, "'unterminated\\'"}, } for _, x := range tests { t.Run(x.str, func(t *testing.T) { res := lex(x.str) if res != x.res { t.Errorf("got %d, want %d", res, x.res) } }) } }