Email adventures

lpeg_patterns/email.lua

@@ -8,13 +8,18 @@ local S = lpeg.S
 local V = lpeg.V
 local C = lpeg.C
 local Cg = lpeg.Cg
-local Ct = lpeg.Ct
 local Cs = lpeg.Cs
+local Ct = lpeg.Ct
 
 local core = require "lpeg_patterns.core"
+
+local printable_character = lpeg.R("\33\126")
+
+local ALPHA = core.ALPHA
 local CHAR = core.CHAR
 local CRLF = core.CRLF
 local CTL = core.CTL
+local DIGIT = core.DIGIT
 local DQUOTE = core.DQUOTE
 local WSP = core.WSP
 local VCHAR = core.VCHAR
@@ -34,7 +39,7 @@ local comment = P {
 	ccontent = ctext + quoted_pair + V"comment" ;
 	comment = P"("* (FWS^-1 * V"ccontent")^0 * FWS^-1 * P")";
 }
-local CFWS = ((FWS^-1 * comment)^1 * FWS^-1 + FWS ) / function() end
+local CFWS = ((FWS^-1 * comment)^1 * FWS^-1 + FWS ) / 0
 
 -- Atom
 local specials      = S[=[()<>@,;:\".[]]=]
@@ -51,41 +56,230 @@ local quoted_string      = CFWS^-1 * quoted_string_text * CFWS^-1
 
 -- Miscellaneous Tokens
 local word = atom + quoted_string
-local obs_phrase = C(word * (word + P"." + CFWS)^0 / function() end)
+local obs_phrase = Cs(word / 1 * (word / 1 + P"." + CFWS / " ")^0)
 local phrase = obs_phrase -- obs_phrase is more broad than `word^1`, it's really the same but allows "."
 
 -- Addr-spec
 local obs_dtext = obs_NO_WS_CTL + quoted_pair
 local dtext = R("\33\90", "\94\126") + obs_dtext
 local domain_literal_text = P"[" * Cs((FWS^-1 * dtext)^0 * FWS^-1) * P"]"
 
-local domain_text     = dot_atom_text + domain_literal_text
+-- A non-spec-compliant variant that does not allow comments or folding whitespace
+local domain_text = dot_atom_text + domain_literal_text
 local local_part_text = dot_atom_text + quoted_string_text
-local addr_spec_text  = local_part_text * P"@" * domain_text
+local addr_spec_text = local_part_text * P"@" * domain_text
 
 local domain_literal = CFWS^-1 * domain_literal_text * CFWS^-1
 local obs_domain = Ct(atom * (C"." * atom)^0) / table.concat
 local domain = obs_domain + dot_atom + domain_literal
 local obs_local_part = Ct(word * (C"." * word)^0) / table.concat
 local local_part = obs_local_part + dot_atom + quoted_string
-local addr_spec      = local_part * P"@" * domain
+local addr_spec = Cg(local_part, "local-part") * P"@" * Cg(domain, "domain")
 
 local display_name = phrase
 local obs_domain_list = (CFWS + P",")^0 * P"@" * domain
 	* (P"," * CFWS^-1 * (P"@" * domain)^-1)^0
-local obs_route = Cg(Ct(obs_domain_list) * P":", "route")
-local obs_angle_addr = CFWS^-1 * P"<" * obs_route * addr_spec * P">" * CFWS^-1
-local angle_addr = CFWS^-1 * P"<" * addr_spec * P">" * CFWS^-1
+local obs_route = Ct(obs_domain_list) * P":"
+local obs_angle_addr = CFWS^-1 * P"<" * Cg(obs_route, "route") * C(addr_spec) * P">" * CFWS^-1
+local angle_addr = CFWS^-1 * P"<" * C(addr_spec) * P">" * CFWS^-1
 	+ obs_angle_addr
-local name_addr = Cg(display_name, "display")^-1 * angle_addr
-local mailbox = name_addr + addr_spec
+local name_addr = Cg(display_name^-1, "display") * angle_addr
+local mailbox = name_addr + C(addr_spec)
+
+-- https://www.rfc-editor.org/rfc/rfc5322#section-2.2
+-- Header fields are lines beginning with a field name, followed by a
+-- colon (":"), followed by a field body, and terminated by CRLF.  A
+-- field name MUST be composed of printable US-ASCII characters (i.e.,
+-- characters that have values between 33 and 126, inclusive), except
+-- colon.  A field body may be composed of printable US-ASCII characters
+-- as well as the space (SP, ASCII value 32) and horizontal tab (HTAB,
+-- ASCII value 9) characters (together known as the white space
+-- characters, WSP).  A field body MUST NOT include CR and LF except
+-- when used in "folding" and "unfolding", as described in section
+-- 2.2.3.  All field bodies MUST conform to the syntax described in
+-- sections 3 and 4 of this specification.
+-- local ftext = S("\33\57","\59\126")
+-- local field_name = ftext^1
+-- local header_field_body = R("\33\126") + FWS
+
+-- RFC 5322 Section 3.4
+local obs_mbox_list = (CFWS^-1 * P",")^0 * Ct(mailbox) * (P"," * (Ct(mailbox) + CFWS)^-1)^0
+-- mailbox_list is a super-set of obs_mbox_list that allowed empty fields
+local mailbox_list = obs_mbox_list
+local obs_group_list = (CFWS^-1 * P",")^1 * CFWS^-1
+local group_list = mailbox_list + CFWS + obs_group_list
+local group = Cg(display_name, "display") * P":" * Cg(Ct(group_list^-1), "members") * P";" * CFWS^-1
+local address = mailbox + group
+local obs_addr_list = (CFWS^-1 * P",")^0 * Ct(address) * (P"," * (Ct(address) + CFWS)^-1)^0
+-- address_list is a super-set of obs_addr_list that allowed empty fields
+local address_list = obs_addr_list
+
+-- RFC 5322 Section 4.5.4
+local obs_id_left = local_part
+local obs_id_right = domain
+
+-- RFC 5322 Section 3.6.4
+local no_fold_literal = P"[" * dtext^0 * P"]"
+local id_left = dot_atom_text + obs_id_left
+local id_right = dot_atom_text + no_fold_literal + obs_id_right
+-- Semantically, the angle bracket characters are not part of the
+-- msg-id; the msg-id is what is contained between the two angle bracket
+-- characters.
+local msg_id = CFWS^-1 * P"<" * C(id_left * P"@" * id_right) * ">" * CFWS^-1
+
+-- RFC 5987
+local mime_charsetc = ALPHA + DIGIT + S"!#$%&+-^_`{}~"
+local mime_charset = C(mime_charsetc^1)
+
+-- RFC 2047
+local charset = mime_charset / string.lower
+local encoding = mime_charset / string.lower
+local encoded_text = (printable_character - S"?")^1
+local encoded_word = P"=?" * charset * P"?" * encoding * P"?" * C(encoded_text) * P"?="
+
+local date_time do -- RFC 5322 Section 3.3
+	local _2DIGIT = DIGIT * DIGIT
+	local _4DIGIT = _2DIGIT * _2DIGIT
+
+	local function tonumber_10(s)
+	   return tonumber(s, 10)
+	end
+
+	-- captured value follow's Lua's os.date yday convention
+	local day_name = (P"Mon" + P"Tue" + P"Wed" + P"Thu" + P"Fri" + P"Sat" + P"Sun") / {
+	   Mon = 2;
+	   Tue = 3;
+	   Wed = 4;
+	   Thu = 5;
+	   Fri = 6;
+	   Sat = 7;
+	   Sun = 1;
+	}
+	local obs_day_of_week = CFWS^-1 * day_name * CFWS^-1
+	local day_of_week = obs_day_of_week
+	local obs_day = CFWS^-1 * (_2DIGIT^1 / tonumber_10) * CFWS^-1
+	local day = obs_day / 1
+	local month = (P"Jan"+ P"Feb"+ P"Mar"+ P"Apr"+ P"May"+ P"Jun"+ P"Jul"+ P"Aug"+ P"Sep"+ P"Oct"+ P"Nov"+ P"Dec") / {
+	   Jan = 1;
+	   Feb = 2;
+	   Mar = 3;
+	   Apr = 4;
+	   May = 5;
+	   Jun = 6;
+	   Jul = 7;
+	   Aug = 8;
+	   Sep = 9;
+	   Oct = 10;
+	   Nov = 11;
+	   Dec = 12;
+	}
+	local obs_year = CFWS^-1 * DIGIT^2 * CFWS^-1 / function(y)
+	   local r = tonumber_10(y)
+
+	   -- If a two digit year is encountered whose value is between 00 and 49,
+	   -- the year is interpreted by adding 2000, ending up with a value between 2000 and 2049.
+	   if #y == 2 and r < 50 then
+	      return r + 2000
+	   end
+
+	   -- If a two digit year is encountered with a value between 50 and 99,
+	   -- or any three digit year is encountered, the year is interpreted by adding 1900.
+	   if #y <= 3 then
+	      return r + 1900
+	   end
+
+	   return r
+	end
+	local year = obs_year / 1
+	local date = Cg(day, "day") * Cg(month, "month") * Cg(year, "year")
+
+	local obs_hour = CFWS^-1 * (_2DIGIT / tonumber_10) * CFWS^-1
+	local hour = obs_hour / 1
+	local obs_minute = CFWS^-1 * (_2DIGIT / tonumber_10) * CFWS^-1
+	local minute = obs_minute / 1
+	local obs_second = CFWS^-1 * (_2DIGIT / tonumber_10) * CFWS^-1
+	local second = obs_second / 1
+	local time_of_day = Cg(hour, "hour") * P":" * Cg(minute, "min") * (P":" * Cg(second, "sec"))^-1
+	local obs_zone = (P"UT" + P"GMT") / "+0000"
+	   + P"EST" / "-0500"
+	   + P"EDT" / "-0400"
+	   + P"CST" / "-0600"
+	   + P"CDT" / "-0500"
+	   + P"MST" / "-0700"
+	   + P"MDT" / "-0600"
+	   + P"PST" / "-0800"
+	   + P"PDT" / "-0700"
+	   + R("\65\73", "\75\90", "\97\105", "\107\122") / "-0000"
+	-- the FWS isn't optional in RFC5322
+	local zone = FWS^-1 / 0 * C(S"+-" * _4DIGIT) + obs_zone
+	local time = time_of_day * Cg(zone, "zone")
+
+	date_time = (Cg(day_of_week, "wday") * P",")^-1 * date * time * CFWS^-1
+end
 
 return {
-	local_part = local_part;
+	obs_NO_WS_CTL = obs_NO_WS_CTL;
+	obs_qp = obs_qp;
+	quoted_pair = quoted_pair;
+	FWS = FWS;
+	ctext = ctext;
+	comment = comment;
+	CFWS = CFWS;
+	specials = specials;
+	atext = atext;
+	atom = atom;
+	dot_atom_text = dot_atom_text;
+	dot_atom = dot_atom;
+	qtext = qtext;
+	qcontent = qcontent;
+	quoted_string_text = quoted_string_text;
+	quoted_string = quoted_string;
+	word = word;
+	obs_phrase = obs_phrase;
+	phrase = phrase;
+	obs_dtext = obs_dtext;
+	dtext = dtext;
+	domain_literal_text = domain_literal_text;
+	domain_literal = domain_literal;
+	obs_domain = obs_domain;
 	domain = domain;
-	email = addr_spec;
+	obs_local_part = obs_local_part;
+	local_part = local_part;
+	addr_spec = addr_spec;
+	display_name = display_name;
+	obs_domain_list = obs_domain_list;
+	obs_route = obs_route;
+	obs_angle_addr = obs_angle_addr;
+	angle_addr = angle_addr;
 	name_addr = name_addr;
 	mailbox = mailbox;
+	-- ftext = ftext;
+	-- field_name = field_name;
+	-- header_field_body = header_field_body;
+	obs_mbox_list = obs_mbox_list;
+	mailbox_list = mailbox_list;
+	obs_group_list = obs_group_list;
+	group_list = group_list;
+	group = group;
+	address = address;
+	obs_addr_list = obs_addr_list;
+	address_list = address_list;
+	obs_id_left = obs_id_left;
+	obs_id_right = obs_id_right;
+	no_fold_literal = no_fold_literal;
+	id_left = id_left;
+	id_right = id_right;
+	msg_id = msg_id;
+	mime_charsetc = mime_charsetc;
+	mime_charset = mime_charset;
+	charset = charset;
+	encoding = encoding;
+	encoded_text = encoded_text;
+	encoded_word = encoded_word;
+	date_time = date_time;
+
+	-- Handy alias
+	email = addr_spec;
 
 	-- A variant that does not allow comments or folding whitespace
 	local_part_nocfws = local_part_text;

lpeg_patterns/http/origin.lua

@@ -9,7 +9,7 @@ local C = lpeg.C
 local P = lpeg.P
 
 -- discard captures from scheme, host, port and just get whole string
-local serialized_origin = C(uri.scheme * P"://" * uri.host * (P":" * uri.port)^-1/function() end)
+local serialized_origin = C(uri.scheme * P"://" * uri.host * (P":" * uri.port)^-1/0)
 local origin_list = serialized_origin * (core.SP * serialized_origin)^0
 local origin_list_or_null = P"null" + origin_list
 local Origin = http_core.OWS * origin_list_or_null * http_core.OWS

lpeg_patterns/language.lua

@@ -77,6 +77,6 @@ local irregular = P"en-GB-oed"
 
 M.Language_Tag = C((M.langtag
 	+ M.privateuse
-	+ irregular) / function() end) -- capture the whole tag. throws away decomposition
+	+ irregular) / 0) -- capture the whole tag. throws away decomposition
 
 return M

spec/email_spec.lua

@@ -157,3 +157,7 @@ describe("mailbox", function()
 			mailbox:match "<@wow,@such,,@domains:[email protected]>")
 	end)
 end)
+describe("date", function()
+	local date_time = lpeg.Ct(require "lpeg_patterns.email".date_time) * EOF
+	assert.same({year=2022, month=5, day=22, hour=2, min=15, sec=14, zone="+0100", wday=1}, date_time:match("Sun, 22 May 2022 02:15:14 +0100"))
+end)