diff --git a/race.log b/race.log
new file mode 100644
index 0000000..87738a5
--- /dev/null
+++ b/race.log
@@ -0,0 +1,275 @@
+mkdir -p "/home/ndumas/work/wikilink-parser/reports"
+mkdir -p "/home/ndumas/work/wikilink-parser/dist"
+go clean code.ndumas.com/ndumas/wikilink-parser
+rm -vrf "/home/ndumas/work/wikilink-parser/dist"/*
+rm -vf "/home/ndumas/work/wikilink-parser/reports"/*
+removed '/home/ndumas/work/wikilink-parser/reports/test.out'
+go get -d -t code.ndumas.com/ndumas/wikilink-parser/...
+go install golang.org/x/tools/cmd/stringer@latest
+go generate
+go test -race -v -tags "release" $(go list "code.ndumas.com/ndumas/wikilink-parser/..." | grep -v /vendor/) | tee "/home/ndumas/work/wikilink-parser/reports/test.out"
+=== RUN   Test_Lexer
+=== RUN   Test_Lexer/wikilink
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":10,"width":1,"item":"ItemIdent:\"wikilink\""}
+2023/07/01 18:25:42 lexCloseLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":12,"width":1,"item":"ItemCloseLink:\"]]\""}
+=== RUN   Test_Lexer/wikilink|display_name
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":12,"width":0,"item":"ItemText:\"\""}
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":10,"width":1,"item":"ItemIdent:\"wikilink\""}
+2023/07/01 18:25:42 lexAlias
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":11,"width":1,"item":"ItemAlias:\"|\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":23,"width":1,"item":"ItemIdent:\"display name\""}
+2023/07/01 18:25:42 lexCloseLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":25,"width":1,"item":"ItemCloseLink:\"]]\""}
+=== RUN   Test_Lexer/wikilink|display_name|second_pipe
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":10,"width":1,"item":"ItemIdent:\"wikilink\""}
+2023/07/01 18:25:42 lexAlias
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":11,"width":1,"item":"ItemAlias:\"|\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":23,"width":1,"item":"ItemIdent:\"display name\""}
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":25,"width":0,"item":"ItemText:\"\""}
+2023/07/01 18:25:42 lexAlias
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":24,"width":1,"item":"ItemAlias:\"|\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":35,"width":1,"item":"ItemIdent:\"second pipe\""}
+2023/07/01 18:25:42 lexCloseLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":37,"width":1,"item":"ItemCloseLink:\"]]\""}
+=== RUN   Test_Lexer/wikilink_with_numeric_alias|420|second_pipe
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":10,"width":1,"item":"ItemIdent:\"wikilink\""}
+2023/07/01 18:25:42 lexAlias
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":11,"width":1,"item":"ItemAlias:\"|\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":14,"width":1,"item":"ItemIdent:\"420\""}
+2023/07/01 18:25:42 lexAlias
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":15,"width":1,"item":"ItemAlias:\"|\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":26,"width":1,"item":"ItemIdent:\"second pipe\""}
+2023/07/01 18:25:42 lexCloseLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":28,"width":1,"item":"ItemCloseLink:\"]]\""}
+=== RUN   Test_Lexer/wikilink_with_spaces_in_filename
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":17,"width":1,"item":"ItemIdent:\"wikilink spaces\""}
+2023/07/01 18:25:42 lexCloseLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":19,"width":1,"item":"ItemCloseLink:\"]]\""}
+=== RUN   Test_Lexer/#heading
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":10,"width":1,"item":"ItemIdent:\"#heading\""}
+    lexer_test.go:100: expected Type ItemHeading, received ItemIdent
+    lexer_test.go:105: expected Value "#", received "#heading"
+2023/07/01 18:25:42 lexCloseLink
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":12,"width":1,"item":"ItemCloseLink:\"]]\""}
+    lexer_test.go:100: expected Type ItemIdent, received ItemCloseLink
+    lexer_test.go:105: expected Value "heading", received "]]"
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":12,"width":0,"item":"ItemText:\"\""}
+    lexer_test.go:100: expected Type ItemCloseLink, received ItemText
+    lexer_test.go:105: expected Value "]]", received ""
+=== RUN   Test_Lexer/wikilink#heading
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":37,"width":0,"item":"ItemText:\"\""}
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":28,"width":0,"item":"ItemText:\"\""}
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":19,"width":0,"item":"ItemText:\"\""}
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":12,"width":0,"item":"ItemText:\"\""}
+2023/07/01 18:25:42 lexText
+2023/07/01 18:25:42 lexOpenLink
+2023/07/01 18:25:42 lexText
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":2,"width":0,"item":"ItemOpenLink:\"[[\""}
+2023/07/01 18:25:42 lexIdent
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":10,"width":1,"item":"ItemIdent:\"wikilink\""}
+==================
+WARNING: DATA RACE
+Read at 0x00c0000822b0 by goroutine 21:
+  code.ndumas.com/ndumas/wikilink-parser.lexText()
+      /home/ndumas/work/wikilink-parser/states.go:82 +0x69
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).run()
+      /home/ndumas/work/wikilink-parser/lexer.go:149 +0x3a
+  code.ndumas.com/ndumas/wikilink-parser.Lex.func1()
+      /home/ndumas/work/wikilink-parser/lexer.go:45 +0x39
+
+Previous write at 0x00c0000822b0 by goroutine 20:
+  code.ndumas.com/ndumas/wikilink-parser.lexOpenLink()
+      /home/ndumas/work/wikilink-parser/states.go:96 +0x86
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).NextItem()
+      /home/ndumas/work/wikilink-parser/lexer.go:64 +0xd5
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:98 +0x18c
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+
+Goroutine 21 (running) created at:
+  code.ndumas.com/ndumas/wikilink-parser.Lex()
+      /home/ndumas/work/wikilink-parser/lexer.go:45 +0x41a
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:95 +0x69
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+
+Goroutine 20 (running) created at:
+  testing.(*T).Run()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x75d
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:93 +0x1086
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+==================
+==================
+WARNING: DATA RACE
+Write at 0x00c0000822b8 by goroutine 21:
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).next()
+      /home/ndumas/work/wikilink-parser/lexer.go:142 +0xe8
+  code.ndumas.com/ndumas/wikilink-parser.lexText()
+      /home/ndumas/work/wikilink-parser/states.go:85 +0xc4
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).run()
+      /home/ndumas/work/wikilink-parser/lexer.go:149 +0x3a
+  code.ndumas.com/ndumas/wikilink-parser.Lex.func1()
+      /home/ndumas/work/wikilink-parser/lexer.go:45 +0x39
+
+Previous write at 0x00c0000822b8 by goroutine 20:
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).next()
+      /home/ndumas/work/wikilink-parser/lexer.go:142 +0xe8
+  code.ndumas.com/ndumas/wikilink-parser.lexIdent()
+      /home/ndumas/work/wikilink-parser/states.go:31 +0x64
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).NextItem()
+      /home/ndumas/work/wikilink-parser/lexer.go:64 +0xd5
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:98 +0x18c
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+
+Goroutine 21 (running) created at:
+  code.ndumas.com/ndumas/wikilink-parser.Lex()
+      /home/ndumas/work/wikilink-parser/lexer.go:45 +0x41a
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:95 +0x69
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+
+Goroutine 20 (running) created at:
+  testing.(*T).Run()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x75d
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:93 +0x1086
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+==================
+==================
+WARNING: DATA RACE
+Read at 0x00c0000822a8 by goroutine 21:
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).emit()
+      /home/ndumas/work/wikilink-parser/lexer.go:109 +0x64
+  code.ndumas.com/ndumas/wikilink-parser.lexText()
+      /home/ndumas/work/wikilink-parser/states.go:88 +0xf4
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).run()
+      /home/ndumas/work/wikilink-parser/lexer.go:149 +0x3a
+  code.ndumas.com/ndumas/wikilink-parser.Lex.func1()
+      /home/ndumas/work/wikilink-parser/lexer.go:45 +0x39
+
+Previous write at 0x00c0000822a8 by goroutine 20:
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).emit()
+      /home/ndumas/work/wikilink-parser/lexer.go:119 +0x4cf
+  code.ndumas.com/ndumas/wikilink-parser.lexOpenLink()
+      /home/ndumas/work/wikilink-parser/states.go:97 +0xa4
+  code.ndumas.com/ndumas/wikilink-parser.(*Lexer).NextItem()
+      /home/ndumas/work/wikilink-parser/lexer.go:64 +0xd5
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:98 +0x18c
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+
+Goroutine 21 (running) created at:
+  code.ndumas.com/ndumas/wikilink-parser.Lex()
+      /home/ndumas/work/wikilink-parser/lexer.go:45 +0x41a
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:95 +0x69
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+
+Goroutine 20 (running) created at:
+  testing.(*T).Run()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x75d
+  code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer()
+      /home/ndumas/work/wikilink-parser/lexer_test.go:93 +0x1086
+  testing.tRunner()
+      /usr/lib/golang/src/testing/testing.go:1446 +0x216
+  testing.(*T).Run.func1()
+      /usr/lib/golang/src/testing/testing.go:1493 +0x47
+==================
+2023/07/01 18:25:42 lexHeading
+{"level":"debug","logger":"lexer.emit","msg":"emitting item","pos":20,"width":0,"item":"ItemText:\"wikilink#heading]]\""}
+    testing.go:1319: race detected during execution of test
+--- FAIL: Test_Lexer (0.01s)
+    --- PASS: Test_Lexer/wikilink (0.00s)
+    --- PASS: Test_Lexer/wikilink|display_name (0.00s)
+    --- PASS: Test_Lexer/wikilink|display_name|second_pipe (0.00s)
+    --- PASS: Test_Lexer/wikilink_with_numeric_alias|420|second_pipe (0.00s)
+    --- PASS: Test_Lexer/wikilink_with_spaces_in_filename (0.00s)
+    --- FAIL: Test_Lexer/#heading (0.00s)
+    --- FAIL: Test_Lexer/wikilink#heading (0.00s)
+panic: runtime error: slice bounds out of range [:21] with length 20 [recovered]
+	panic: runtime error: slice bounds out of range [:21] with length 20
+
+goroutine 34 [running]:
+testing.tRunner.func1.2({0x6e8160, 0xc0000e20a8})
+	/usr/lib/golang/src/testing/testing.go:1396 +0x372
+testing.tRunner.func1()
+	/usr/lib/golang/src/testing/testing.go:1399 +0x5f0
+panic({0x6e8160, 0xc0000e20a8})
+	/usr/lib/golang/src/runtime/panic.go:890 +0x262
+code.ndumas.com/ndumas/wikilink-parser.(*Lexer).emit(0xc000082280, 0x5)
+	/home/ndumas/work/wikilink-parser/lexer.go:109 +0x506
+code.ndumas.com/ndumas/wikilink-parser.lexHeading(0xc000082280)
+	/home/ndumas/work/wikilink-parser/states.go:58 +0xa5
+code.ndumas.com/ndumas/wikilink-parser.(*Lexer).NextItem(0xc000082280)
+	/home/ndumas/work/wikilink-parser/lexer.go:64 +0xd6
+code.ndumas.com/ndumas/wikilink-parser_test.Test_Lexer.func1(0xc000190b60)
+	/home/ndumas/work/wikilink-parser/lexer_test.go:98 +0x18d
+testing.tRunner(0xc000190b60, 0xc00019cb40)
+	/usr/lib/golang/src/testing/testing.go:1446 +0x217
+created by testing.(*T).Run
+	/usr/lib/golang/src/testing/testing.go:1493 +0x75e
+FAIL	code.ndumas.com/ndumas/wikilink-parser	0.024s
+FAIL