29 April 2019
Très bonne formalisation des différentes syntaxe pour définir des grammaires sur le site de :
* lmu : Syntax
Format railroad :
Editeur de schémas railroad à partir d'une grammaire EBNF.
Une grammaire de l'organisation d'un email, en fonction des RFC est donnée ici, mais le formalisme est étrange.
Grammaire originale :
1. NUL = "ASCII code zero" ;
2. HTAB = "ASCII code 9" ;
3. LF = "ASCII code 10" ;
4. CR = "ASCII code 13" ;
5. CRLF = CR4 LF3 ;
6. SP = "ASCII code 32" ;
7. WSP = SP6 | HTAB2 ;
8. ALPHA = "A".."Z" | "a".."z" ;
9. DIGIT = "0".."9" ;
10. DQUOTE = "\"" ;
11. VCHAR = "!".."~" ;
12. quoted_pair = "\\" ( VCHAR11 | WSP7 ) | obs_qp96 ;
13. FWS = [ { WSP7 } CRLF5 ] WSP7 { WSP7 } | obs_FWS101 ;
14. ctext = "!".."'" | "*".."[" | "]".."~" | obs_ctext93 ;
15. ccontent = ctext14 | quoted_pair12 | comment16 ;
16. comment = "(" { [ FWS13 ] ccontent15 } [ FWS13 ] ")" ;
17. CFWS = [ FWS13 ] comment16 { [ FWS13 ] comment16 } [ FWS13 ] | FWS13 ;
18. atext = ALPHA8 | DIGIT9 | "!" | "#" | "$" | "%" | "&" | "'" | "*" | "+" | "-" | "/" | "=" | "?" | "^" | "_" | "`" | "{" | "|" | "}" | "~" ;
19. atom = [ CFWS17 ] atext18 { atext18 } [ CFWS17 ] ;
20. dot_atom_text = atext18 { atext18 } { "." atext18 { atext18 } } ;
21. dot_atom = [ CFWS17 ] dot_atom_text20 [ CFWS17 ] ;
22. specials = "(" | ")" | "<" | ">" | "[" | "]" | ":" | ";" | "@" | "\\" | "," | "." | DQUOTE10 ;
23. qtext = "!" | "#".."[" | "]".."~" | obs_qtext94 ;
24. qcontent = qtext23 | quoted_pair12 ;
25. quoted_string = [ CFWS17 ] DQUOTE10 { [ FWS13 ] qcontent24 } [ FWS13 ] DQUOTE10 [ CFWS17 ] ;
26. word = atom19 | quoted_string25 ;
27. phrase = word26 { word26 } | obs_phrase99 ;
28. unstructured = { [ FWS13 ] VCHAR11 } { WSP7 } | obs_unstruct98 ;
29. date_time = [ day_of_week30 "," ] date32 time36 [ CFWS17 ] ;
30. day_of_week = [ FWS13 ] day_name31 | obs_day_of_week102 ;
31. day_name = "Mon" | "Tue" | "Wed" | "Thu" | "Fri" | "Sat" | "Sun" ;
32. date = day33 month34 year35 ;
33. day = [ FWS13 ] DIGIT9 [ DIGIT9 ] FWS13 | obs_day103 ;
34. month = "Jan" | "Feb" | "Mar" | "Apr" | "May" | "Jun" | "Jul" | "Aug" | "Sep" | "Oct" | "Nov" | "Dec" ;
35. year = FWS13 DIGIT9 DIGIT9 DIGIT9 DIGIT9 FWS13 | obs_year104 ;
36. time = time_of_day37 zone41 ;
37. time_of_day = hour38 ":" minute39 [ ":" second40 ] ;
38. hour = DIGIT9 DIGIT9 | obs_hour105 ;
39. minute = DIGIT9 DIGIT9 | obs_minute106 ;
40. second = DIGIT9 DIGIT9 | obs_second107 ;
41. zone = FWS13 ( "+" | "-" ) DIGIT9 DIGIT9 DIGIT9 DIGIT9 | obs_zone108 ;
42. address = mailbox43 | group46 ;
43. mailbox = name_addr44 | addr_spec51 ;
44. name_addr = [ display_name47 ] angle_addr45 ;
45. angle_addr = [ CFWS17 ] "<" addr_spec51 ">" [ CFWS17 ] | obs_angle_addr109 ;
46. group = display_name47 ":" [ group_list50 ] ";" [ CFWS17 ] ;
47. display_name = phrase27 ;
48. mailbox_list = mailbox43 { "," mailbox43 } | obs_mbox_list112 ;
49. address_list = address42 { "," address42 } | obs_addr_list113 ;
50. group_list = mailbox_list48 | CFWS17 | obs_group_list114 ;
51. addr_spec = local_part52 "@" domain53 ;
52. local_part = dot_atom21 | quoted_string25 | obs_local_part115 ;
53. domain = dot_atom21 | domain_literal54 | obs_domain116 ;
54. domain_literal = [ CFWS17 ] "[" { [ FWS13 ] dtext55 } [ FWS13 ] "]" [ CFWS17 ] ;
55. dtext = "!".."Z" | "^".."~" | obs_dtext117 ;
56. message = ( fields59 | obs_fields118 ) [ CRLF5 body57 ] ;
57. body = { { text58 } CRLF5 } { text58 } | obs_body97 ;
58. text = "ASCII codes: 1-9, 11, 12, 14-127" ;
59. fields = { trace84 { optional_field89 } | { resent_date77 | resent_from78 | resent_sender79 | resent_to80 | resent_cc81 | resent_bcc82 | resent_msg_id83 } } { orig_date60 | from61 | sender62 | reply_to63 | to64 | cc65 | bcc66 | message_id67 | in_reply_to68 | references69 | subject74 | comments75 | keywords76 | optional_field89 } ;
60. orig_date = "Date:" date_time29 CRLF5 ;
61. from = "From:" mailbox_list48 CRLF5 ;
62. sender = "Sender:" mailbox43 CRLF5 ;
63. reply_to = "Reply_To:" address_list49 CRLF5 ;
64. to = "To:" address_list49 CRLF5 ;
65. cc = "Cc:" address_list49 CRLF5 ;
66. bcc = "Bcc:" [ address_list49 | CFWS17 ] CRLF5 ;
67. message_id = "Message_ID:" msg_id70 CRLF5 ;
68. in_reply_to = "In_Reply_To:" msg_id70 { msg_id70 } CRLF5 ;
69. references = "References:" msg_id70 { msg_id70 } CRLF5 ;
70. msg_id = [ CFWS17 ] "<" id_left71 "@" id_right72 ">" [ CFWS17 ] ;
71. id_left = dot_atom_text20 | obs_id_left129 ;
72. id_right = dot_atom_text20 | no_fold_literal73 | obs_id_right130 ;
73. no_fold_literal = "[" { dtext55 } "]" ;
74. subject = "Subject:" unstructured28 CRLF5 ;
75. comments = "Comments:" unstructured28 CRLF5 ;
76. keywords = "Keywords:" phrase27 { "," phrase27 } CRLF5 ;
77. resent_date = "Resent_Date:" date_time29 CRLF5 ;
78. resent_from = "Resent_From:" mailbox_list48 CRLF5 ;
79. resent_sender = "Resent_Sender:" mailbox43 CRLF5 ;
80. resent_to = "Resent_To:" address_list49 CRLF5 ;
81. resent_cc = "Resent_Cc:" address_list49 CRLF5 ;
82. resent_bcc = "Resent_Bcc:" [ address_list49 | CFWS17 ] CRLF5 ;
83. resent_msg_id = "Resent_Message_ID:" msg_id70 CRLF5 ;
84. trace = [ return85 ] received87 { received87 } ;
85. return = "Return_Path:" path86 CRLF5 ;
86. path = angle_addr45 | [ CFWS17 ] "<" [ CFWS17 ] ">" [ CFWS17 ] ;
87. received = "Received:" { received_token88 } ";" date_time29 CRLF5 ;
88. received_token = word26 | angle_addr45 | addr_spec51 | domain53 ;
89. optional_field = field_name90 ":" unstructured28 CRLF5 ;
90. field_name = ftext91 { ftext91 } ;
91. ftext = "!".."9" | ";".."~" ;
92. obs_NO_WS_CTL = "ASCII codes 1-8, 11, 12, 14-31, 127" ;
93. obs_ctext = obs_NO_WS_CTL92 ;
94. obs_qtext = obs_NO_WS_CTL92 ;
95. obs_utext = NUL1 | obs_NO_WS_CTL92 | VCHAR11 ;
96. obs_qp = "\\" ( NUL1 | obs_NO_WS_CTL92 | LF3 | CR4 ) ;
97. obs_body = { { LF3 } { CR4 } { ( NUL1 | text58 ) { LF3 } { CR4 } } | CRLF5 } ;
98. obs_unstruct = { { LF3 } { CR4 } { obs_utext95 { LF3 } { CR4 } } | FWS13 } ;
99. obs_phrase = word26 { word26 | "." | CFWS17 } ;
100. obs_phrase_list = [ phrase27 | CFWS17 ] { "," [ phrase27 | CFWS17 ] } ;
101. obs_FWS = WSP7 { WSP7 } { CRLF5 WSP7 { WSP7 } } ;
102. obs_day_of_week = [ CFWS17 ] day_name31 [ CFWS17 ] ;
103. obs_day = [ CFWS17 ] DIGIT9 [ DIGIT9 ] [ CFWS17 ] ;
104. obs_year = [ CFWS17 ] DIGIT9 DIGIT9 { DIGIT9 } [ CFWS17 ] ;
105. obs_hour = [ CFWS17 ] DIGIT9 DIGIT9 [ CFWS17 ] ;
106. obs_minute = [ CFWS17 ] DIGIT9 DIGIT9 [ CFWS17 ] ;
107. obs_second = [ CFWS17 ] DIGIT9 DIGIT9 [ CFWS17 ] ;
108. obs_zone = "UT" | "GMT" | "EST" | "EDT" | "CST" | "CDT" | "MST" | "MDT" | "PST" | "PDT" | "A".."I" | "K".."Z" | "a".."i" | "k".."z" ;
109. obs_angle_addr = [ CFWS17 ] "<" obs_route110 addr_spec51 ">" [ CFWS17 ] ;
110. obs_route = obs_domain_list111 ":" ;
111. obs_domain_list = { CFWS17 | "," } "@" domain53 { "," [ CFWS17 ] [ "@" domain53 ] } ;
112. obs_mbox_list = { [ CFWS17 ] "," } mailbox43 { "," [ mailbox43 | CFWS17 ] } ;
113. obs_addr_list = { [ CFWS17 ] "," } address42 { "," [ address42 | CFWS17 ] } ;
114. obs_group_list = [ CFWS17 ] "," { [ CFWS17 ] "," } [ CFWS17 ] ;
115. obs_local_part = word26 { "." word26 } ;
116. obs_domain = atom19 { "." atom19 } ;
117. obs_dtext = obs_NO_WS_CTL92 | quoted_pair12 ;
118. obs_fields = { obs_return142 | obs_received143 | obs_orig_date119 | obs_from120 | obs_sender121 | obs_reply_to122 | obs_to123 | obs_cc124 | obs_bcc125 | obs_message_id126 | obs_in_reply_to127 | obs_references128 | obs_subject131 | obs_comments132 | obs_keywords133 | obs_resent_date136 | obs_resent_from134 | obs_resent_send135 | obs_resent_rply141 | obs_resent_to137 | obs_resent_cc138 | obs_resent_bcc139 | obs_resent_mid140 | obs_optional144 } ;
119. obs_orig_date = "Date" { WSP7 } ":" date_time29 CRLF5 ;
120. obs_from = "From" { WSP7 } ":" mailbox_list48 CRLF5 ;
121. obs_sender = "Sender" { WSP7 } ":" mailbox43 CRLF5 ;
122. obs_reply_to = "Reply_To" { WSP7 } ":" address_list49 CRLF5 ;
123. obs_to = "To" { WSP7 } ":" address_list49 CRLF5 ;
124. obs_cc = "Cc" { WSP7 } ":" address_list49 CRLF5 ;
125. obs_bcc = "Bcc" { WSP7 } ":" ( address_list49 | { [ CFWS17 ] "," } [ CFWS17 ] ) CRLF5 ;
126. obs_message_id = "Message_ID" { WSP7 } ":" msg_id70 CRLF5 ;
127. obs_in_reply_to = "In_Reply_To" { WSP7 } ":" { phrase27 | msg_id70 } CRLF5 ;
128. obs_references = "References" { WSP7 } ":" { phrase27 | msg_id70 } CRLF5 ;
129. obs_id_left = local_part52 ;
130. obs_id_right = domain53 ;
131. obs_subject = "Subject" { WSP7 } ":" unstructured28 CRLF5 ;
132. obs_comments = "Comments" { WSP7 } ":" unstructured28 CRLF5 ;
133. obs_keywords = "Keywords" { WSP7 } ":" obs_phrase_list100 CRLF5 ;
134. obs_resent_from = "Resent_From" { WSP7 } ":" mailbox_list48 CRLF5 ;
135. obs_resent_send = "Resent_Sender" { WSP7 } ":" mailbox43 CRLF5 ;
136. obs_resent_date = "Resent_Date" { WSP7 } ":" date_time29 CRLF5 ;
137. obs_resent_to = "Resent_To" { WSP7 } ":" address_list49 CRLF5 ;
138. obs_resent_cc = "Resent_Cc" { WSP7 } ":" address_list49 CRLF5 ;
139. obs_resent_bcc = "Resent_Bcc" { WSP7 } ":" ( address_list49 | { [ CFWS17 ] "," } [ CFWS17 ] ) CRLF5 ;
140. obs_resent_mid = "Resent_Message_ID" { WSP7 } ":" msg_id70 CRLF5 ;
141. obs_resent_rply = "Resent_Reply_To" { WSP7 } ":" address_list49 CRLF5 ;
142. obs_return = "Return_Path" { WSP7 } ":" path86 CRLF5 ;
143. obs_received = "Received" { WSP7 } ":" { received_token88 } CRLF5 ;
144. obs_optional = field_name90 { WSP7 } ":" unstructured28 CRLF5 ;
Avec quelques transformations pour que cela ressemble à une grammaire EBNF
(Il reste des problèmes, en particulier pour les ranges de caractères, notés '..' .
En particulier, cela ne fonctionne pas avec le site de railroad ci dessus.
NUL ::= "ASCII code zero" ;
HTAB ::= "ASCII code 9" ;
LF ::= "ASCII code 10" ;
CR ::= "ASCII code 13" ;
CRLF ::= CR4 LF3 ;
SP ::= "ASCII code 32" ;
WSP ::= SP6 | HTAB2 ;
ALPHA ::= "A".."Z" | "a".."z" ;
DIGIT ::= "0".."9" ;
DQUOTE ::= "\"" ;
VCHAR ::= "!".."~" ;
quoted_pair ::= "\\" ( VCHAR11 | WSP7 ) | obs_qp96 ;
FWS ::= [ { WSP7 } CRLF5 ] WSP7 { WSP7 } | obs_FWS101 ;
ctext ::= "!".."'" | "*".."[" | "]".."~" | obs_ctext93 ;
ccontent ::= ctext14 | quoted_pair12 | comment16 ;
comment ::= "(" { [ FWS13 ] ccontent15 } [ FWS13 ] ")" ;
CFWS ::= [ FWS13 ] comment16 { [ FWS13 ] comment16 } [ FWS13 ] | FWS13 ;
atext ::= ALPHA8 | DIGIT9 | "!" | "#" | "$" | "%" | "&" | "'" | "*" | "+" | "-" | "/" | "=" | "?" | "^" | "_" | "`" | "{" | "|" | "}" | "~" ;
atom ::= [ CFWS17 ] atext18 { atext18 } [ CFWS17 ] ;
dot_atom_text ::= atext18 { atext18 } { "." atext18 { atext18 } } ;
dot_atom ::= [ CFWS17 ] dot_atom_text20 [ CFWS17 ] ;
specials ::= "(" | ")" | "<" | ">" | "[" | "]" | ":" | ";" | "@" | "\\" | "," | "." | DQUOTE10 ;
qtext ::= "!" | "#".."[" | "]".."~" | obs_qtext94 ;
qcontent ::= qtext23 | quoted_pair12 ;
quoted_string ::= [ CFWS17 ] DQUOTE10 { [ FWS13 ] qcontent24 } [ FWS13 ] DQUOTE10 [ CFWS17 ] ;
word ::= atom19 | quoted_string25 ;
phrase ::= word26 { word26 } | obs_phrase99 ;
unstructured ::= { [ FWS13 ] VCHAR11 } { WSP7 } | obs_unstruct98 ;
date_time ::= [ day_of_week30 "," ] date32 time36 [ CFWS17 ] ;
day_of_week ::= [ FWS13 ] day_name31 | obs_day_of_week102 ;
day_name ::= "Mon" | "Tue" | "Wed" | "Thu" | "Fri" | "Sat" | "Sun" ;
date ::= day33 month34 year35 ;
day ::= [ FWS13 ] DIGIT9 [ DIGIT9 ] FWS13 | obs_day103 ;
month ::= "Jan" | "Feb" | "Mar" | "Apr" | "May" | "Jun" | "Jul" | "Aug" | "Sep" | "Oct" | "Nov" | "Dec" ;
year ::= FWS13 DIGIT9 DIGIT9 DIGIT9 DIGIT9 FWS13 | obs_year104 ;
time ::= time_of_day37 zone41 ;
time_of_day ::= hour38 ":" minute39 [ ":" second40 ] ;
hour ::= DIGIT9 DIGIT9 | obs_hour105 ;
minute ::= DIGIT9 DIGIT9 | obs_minute106 ;
second ::= DIGIT9 DIGIT9 | obs_second107 ;
zone ::= FWS13 ( "+" | "-" ) DIGIT9 DIGIT9 DIGIT9 DIGIT9 | obs_zone108 ;
address ::= mailbox43 | group46 ;
mailbox ::= name_addr44 | addr_spec51 ;
name_addr ::= [ display_name47 ] angle_addr45 ;
angle_addr ::= [ CFWS17 ] "<" addr_spec51 ">" [ CFWS17 ] | obs_angle_addr109 ;
group ::= display_name47 ":" [ group_list50 ] ";" [ CFWS17 ] ;
display_name ::= phrase27 ;
mailbox_list ::= mailbox43 { "," mailbox43 } | obs_mbox_list112 ;
address_list ::= address42 { "," address42 } | obs_addr_list113 ;
group_list ::= mailbox_list48 | CFWS17 | obs_group_list114 ;
addr_spec ::= local_part52 "@" domain53 ;
local_part ::= dot_atom21 | quoted_string25 | obs_local_part115 ;
domain ::= dot_atom21 | domain_literal54 | obs_domain116 ;
domain_literal ::= [ CFWS17 ] "[" { [ FWS13 ] dtext55 } [ FWS13 ] "]" [ CFWS17 ] ;
dtext ::= "!".."Z" | "^".."~" | obs_dtext117 ;
message ::= ( fields59 | obs_fields118 ) [ CRLF5 body57 ] ;
body ::= { { text58 } CRLF5 } { text58 } | obs_body97 ;
text ::= "ASCII codes: 1-9, 11, 12, 14-127" ;
fields ::= { trace84 { optional_field89 } | { resent_date77 | resent_from78 | resent_sender79 | resent_to80 | resent_cc81 | resent_bcc82 | resent_msg_id83 } } { orig_date60 | from61 | sender62 | reply_to63 | to64 | cc65 | bcc66 | message_id67 | in_reply_to68 | references69 | subject74 | comments75 | keywords76 | optional_field89 } ;
orig_date ::= "Date:" date_time29 CRLF5 ;
from ::= "From:" mailbox_list48 CRLF5 ;
sender ::= "Sender:" mailbox43 CRLF5 ;
reply_to ::= "Reply_To:" address_list49 CRLF5 ;
to ::= "To:" address_list49 CRLF5 ;
cc ::= "Cc:" address_list49 CRLF5 ;
bcc ::= "Bcc:" [ address_list49 | CFWS17 ] CRLF5 ;
message_id ::= "Message_ID:" msg_id70 CRLF5 ;
in_reply_to ::= "In_Reply_To:" msg_id70 { msg_id70 } CRLF5 ;
references ::= "References:" msg_id70 { msg_id70 } CRLF5 ;
msg_id ::= [ CFWS17 ] "<" id_left71 "@" id_right72 ">" [ CFWS17 ] ;
id_left ::= dot_atom_text20 | obs_id_left129 ;
id_right ::= dot_atom_text20 | no_fold_literal73 | obs_id_right130 ;
no_fold_literal ::= "[" { dtext55 } "]" ;
subject ::= "Subject:" unstructured28 CRLF5 ;
comments ::= "Comments:" unstructured28 CRLF5 ;
keywords ::= "Keywords:" phrase27 { "," phrase27 } CRLF5 ;
resent_date ::= "Resent_Date:" date_time29 CRLF5 ;
resent_from ::= "Resent_From:" mailbox_list48 CRLF5 ;
resent_sender ::= "Resent_Sender:" mailbox43 CRLF5 ;
resent_to ::= "Resent_To:" address_list49 CRLF5 ;
resent_cc ::= "Resent_Cc:" address_list49 CRLF5 ;
resent_bcc ::= "Resent_Bcc:" [ address_list49 | CFWS17 ] CRLF5 ;
resent_msg_id ::= "Resent_Message_ID:" msg_id70 CRLF5 ;
trace ::= [ return85 ] received87 { received87 } ;
return ::= "Return_Path:" path86 CRLF5 ;
path ::= angle_addr45 | [ CFWS17 ] "<" [ CFWS17 ] ">" [ CFWS17 ] ;
received ::= "Received:" { received_token88 } ";" date_time29 CRLF5 ;
received_token ::= word26 | angle_addr45 | addr_spec51 | domain53 ;
optional_field ::= field_name90 ":" unstructured28 CRLF5 ;
field_name ::= ftext91 { ftext91 } ;
ftext ::= "!".."9" | ";".."~" ;
obs_NO_WS_CTL ::= "ASCII codes 1-8, 11, 12, 14-31, 127" ;
obs_ctext ::= obs_NO_WS_CTL92 ;
obs_qtext ::= obs_NO_WS_CTL92 ;
obs_utext ::= NUL1 | obs_NO_WS_CTL92 | VCHAR11 ;
obs_qp ::= "\\" ( NUL1 | obs_NO_WS_CTL92 | LF3 | CR4 ) ;
obs_body ::= { { LF3 } { CR4 } { ( NUL1 | text58 ) { LF3 } { CR4 } } | CRLF5 } ;
obs_unstruct ::= { { LF3 } { CR4 } { obs_utext95 { LF3 } { CR4 } } | FWS13 } ;
obs_phrase ::= word26 { word26 | "." | CFWS17 } ;
obs_phrase_list ::= [ phrase27 | CFWS17 ] { "," [ phrase27 | CFWS17 ] } ;
obs_FWS ::= WSP7 { WSP7 } { CRLF5 WSP7 { WSP7 } } ;
obs_day_of_week ::= [ CFWS17 ] day_name31 [ CFWS17 ] ;
obs_day ::= [ CFWS17 ] DIGIT9 [ DIGIT9 ] [ CFWS17 ] ;
obs_year ::= [ CFWS17 ] DIGIT9 DIGIT9 { DIGIT9 } [ CFWS17 ] ;
obs_hour ::= [ CFWS17 ] DIGIT9 DIGIT9 [ CFWS17 ] ;
obs_minute ::= [ CFWS17 ] DIGIT9 DIGIT9 [ CFWS17 ] ;
obs_second ::= [ CFWS17 ] DIGIT9 DIGIT9 [ CFWS17 ] ;
obs_zone ::= "UT" | "GMT" | "EST" | "EDT" | "CST" | "CDT" | "MST" | "MDT" | "PST" | "PDT" | "A".."I" | "K".."Z" | "a".."i" | "k".."z" ;
obs_angle_addr ::= [ CFWS17 ] "<" obs_route110 addr_spec51 ">" [ CFWS17 ] ;
obs_route ::= obs_domain_list111 ":" ;
obs_domain_list ::= { CFWS17 | "," } "@" domain53 { "," [ CFWS17 ] [ "@" domain53 ] } ;
obs_mbox_list ::= { [ CFWS17 ] "," } mailbox43 { "," [ mailbox43 | CFWS17 ] } ;
obs_addr_list ::= { [ CFWS17 ] "," } address42 { "," [ address42 | CFWS17 ] } ;
obs_group_list ::= [ CFWS17 ] "," { [ CFWS17 ] "," } [ CFWS17 ] ;
obs_local_part ::= word26 { "." word26 } ;
obs_domain ::= atom19 { "." atom19 } ;
obs_dtext ::= obs_NO_WS_CTL92 | quoted_pair12 ;
obs_fields ::= { obs_return142 | obs_received143 | obs_orig_date119 | obs_from120 | obs_sender121 | obs_reply_to122 | obs_to123 | obs_cc124 | obs_bcc125 | obs_message_id126 | obs_in_reply_to127 | obs_references128 | obs_subject131 | obs_comments132 | obs_keywords133 | obs_resent_date136 | obs_resent_from134 | obs_resent_send135 | obs_resent_rply141 | obs_resent_to137 | obs_resent_cc138 | obs_resent_bcc139 | obs_resent_mid140 | obs_optional144 } ;
obs_orig_date ::= "Date" { WSP7 } ":" date_time29 CRLF5 ;
obs_from ::= "From" { WSP7 } ":" mailbox_list48 CRLF5 ;
obs_sender ::= "Sender" { WSP7 } ":" mailbox43 CRLF5 ;
obs_reply_to ::= "Reply_To" { WSP7 } ":" address_list49 CRLF5 ;
obs_to ::= "To" { WSP7 } ":" address_list49 CRLF5 ;
obs_cc ::= "Cc" { WSP7 } ":" address_list49 CRLF5 ;
obs_bcc ::= "Bcc" { WSP7 } ":" ( address_list49 | { [ CFWS17 ] "," } [ CFWS17 ] ) CRLF5 ;
obs_message_id ::= "Message_ID" { WSP7 } ":" msg_id70 CRLF5 ;
obs_in_reply_to ::= "In_Reply_To" { WSP7 } ":" { phrase27 | msg_id70 } CRLF5 ;
obs_references ::= "References" { WSP7 } ":" { phrase27 | msg_id70 } CRLF5 ;
obs_id_left ::= local_part52 ;
obs_id_right ::= domain53 ;
obs_subject ::= "Subject" { WSP7 } ":" unstructured28 CRLF5 ;
obs_comments ::= "Comments" { WSP7 } ":" unstructured28 CRLF5 ;
obs_keywords ::= "Keywords" { WSP7 } ":" obs_phrase_list100 CRLF5 ;
obs_resent_from ::= "Resent_From" { WSP7 } ":" mailbox_list48 CRLF5 ;
obs_resent_send ::= "Resent_Sender" { WSP7 } ":" mailbox43 CRLF5 ;
obs_resent_date ::= "Resent_Date" { WSP7 } ":" date_time29 CRLF5 ;
obs_resent_to ::= "Resent_To" { WSP7 } ":" address_list49 CRLF5 ;
obs_resent_cc ::= "Resent_Cc" { WSP7 } ":" address_list49 CRLF5 ;
obs_resent_bcc ::= "Resent_Bcc" { WSP7 } ":" ( address_list49 | { [ CFWS17 ] "," } [ CFWS17 ] ) CRLF5 ;
obs_resent_mid ::= "Resent_Message_ID" { WSP7 } ":" msg_id70 CRLF5 ;
obs_resent_rply ::= "Resent_Reply_To" { WSP7 } ":" address_list49 CRLF5 ;
obs_return ::= "Return_Path" { WSP7 } ":" path86 CRLF5 ;
obs_received ::= "Received" { WSP7 } ":" { received_token88 } CRLF5 ;
obs_optional ::= field_name90 { WSP7 } ":" unstructured28 CRLF5 ;