1 files changed, 54 insertions, 0 deletions
diff --git a/lua/lexers/todotxt.lua b/lua/lexers/todotxt.lua
new file mode 100644
index 0000000..a6d7565
--- /dev/null
+++ b/lua/lexers/todotxt.lua
@@ -0,0 +1,54 @@
+-- Copyright 2025 Chris Clark and Mitchell. See LICENSE.
+-- todo.txt LPeg lexer.
+-- https://github.com/too-much-todotxt/spec
+
+local lexer = lexer
+local P, S = lpeg.P, lpeg.S
+
+local lex = lexer.new(...)
+
+-- Done/Complete items.
+lex:add_rule('done', lex:tag(lexer.COMMENT, lexer.starts_line(lexer.to_eol('x '))))
+
+-- Priority.
+local priority = P(false)
+for letter in string.gmatch('abcdefghijklmnopqrstuvwxyz', '.') do
+	local tag = lex:tag(lexer.LIST .. '.priority.' .. letter,
+		lexer.starts_line('(' .. letter:upper() .. ') '))
+	priority = priority + tag
+end
+lex:add_rule('priority', priority)
+
+-- URLs, emails, and domain names.
+-- Note: this is not part of todo.txt, but is an extension to make editing cleaner.
+local nonspace = lexer.any - lexer.space
+local email = lex:tag(lexer.LINK,
+	(nonspace - '@')^1 * '@' * (nonspace - '.')^1 * ('.' * (nonspace - S('.?'))^1)^1 *
+		('?' * nonspace^1)^-1)
+local host = lex:tag(lexer.LINK,
+	lexer.word_match('www ftp', true) * (nonspace - '.')^0 * '.' * (nonspace - '.')^1 * '.' *
+		(nonspace - S(',.'))^1)
+local url = lex:tag(lexer.LINK,
+	(nonspace - '://')^1 * '://' * (nonspace - ',' - '.')^1 * ('.' * (nonspace - S(',./?#'))^1)^1 *
+		('/' * (nonspace - S('./?#'))^0 * ('.' * (nonspace - S(',.?#'))^1)^0)^0 *
+		('?' * (nonspace - '#')^1)^-1 * ('#' * nonspace^0)^-1)
+local link = url + host + email
+lex:add_rule('link', link)
+
+-- Key-value pairs.
+local word = (lexer.any - lexer.space - P(':'))^1
+local key = lex:tag(lexer.KEYWORD, word)
+local colon = lex:tag(lexer.OPERATOR, P(':'))
+local value = lex:tag(lexer.STRING, word)
+lex:add_rule('key_value', key * colon * value)
+
+-- Dates.
+lex:add_rule('date', lex:tag(lexer.NUMBER, lexer.digit^4 * P('-') * lexer.digit^2 * P('-') *
+	lexer.digit^2 * (#lexer.space + P(-1))))
+
+-- Project +
+lex:add_rule('project', lex:tag(lexer.LABEL, lexer.range('+', lexer.space, true)))
+-- Context @
+lex:add_rule('context', lex:tag(lexer.TYPE, lexer.range('@', lexer.space, true)))
+
+return lex