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a933dad1 DL |
1 | Format of Version 5 Babyl Files: |
2 | ||
ca4ac03d GM |
3 | (Babyl was the storage format used by Rmail before Emacs 23.1. |
4 | Since then it uses mbox format.) | |
5 | ||
a933dad1 DL |
6 | Warning: |
7 | ||
8 | This was written Tuesday, 12 April 1983 (by Eugene Ciccarelli), | |
9 | based on looking at a particular Babyl file and recalling various | |
10 | issues. Therefore it is not guaranteed to be complete, but it is a | |
11 | start, and I will try to point the reader to various Babyl functions | |
12 | that will serve to clarify certain format questions. | |
13 | ||
14 | Also note that this file will not contain control-characters, | |
15 | but instead have two-character sequences starting with Uparrow. | |
16 | Unless otherwise stated, an Uparrow <character> is to be read as | |
17 | Control-<character>, e.g. ^L is a Control-L. | |
18 | ||
19 | Versions: | |
20 | ||
21 | First, note that each Babyl file contains in its BABYL OPTIONS | |
22 | section the version for the Babyl file format. In principle, the | |
23 | format can be changed in any way as long as we increment the format | |
24 | version number; then programs can support both old and new formats. | |
25 | ||
26 | In practice, version 5 is the only format version used, and the | |
27 | previous versions have been obsolete for so long that Emacs does not | |
28 | support them. | |
29 | \f | |
30 | ||
31 | Overall Babyl File Structure: | |
32 | ||
33 | A Babyl file consists of a BABYL OPTIONS section followed by | |
34 | 0 or more message sections. The BABYL OPTIONS section starts | |
35 | with the line "BABYL OPTIONS:". Message sections start with | |
36 | Control-Underscore Control-L Newline. Each section ends | |
37 | with a Control-Underscore. (That is also the first character | |
38 | of the starter for the next section, if any.) Thus, a three | |
39 | message Babyl file looks like: | |
40 | ||
41 | BABYL OPTIONS: | |
42 | ...the stuff within the Babyl Options section... | |
43 | ^_^L | |
44 | ...the stuff within the 1st message section... | |
45 | ^_^L | |
46 | ...the stuff within the 2nd message section... | |
47 | ^_^L | |
48 | ...the stuff within the last message section... | |
49 | ^_ | |
50 | ||
51 | Babyl is tolerant about some whitespace at the end of the | |
52 | file -- the file may end with the final ^_ or it may have some | |
53 | whitespace, e.g. a newline, after it. | |
54 | \f | |
55 | ||
56 | The BABYL OPTIONS Section: | |
57 | ||
58 | Each Babyl option is specified on one line (thus restricting | |
59 | string values these options can currently have). Values are | |
60 | either numbers or strings. The format is name, colon, and the | |
61 | value, with whitespace after the colon ignored, e.g.: | |
62 | ||
63 | Mail: ~/special-inbox | |
64 | ||
65 | Unrecognized options are ignored. | |
66 | ||
67 | Here are those options and the kind of values currently expected: | |
68 | ||
69 | MAIL Filename, the input mail file for this | |
70 | Babyl file. You may also use several file names | |
71 | separated by commas. | |
72 | Version Number. This should always be 5. | |
73 | Labels String, list of labels, separated by commas. | |
74 | \f | |
75 | ||
76 | Message Sections: | |
77 | ||
78 | A message section contains one message and information | |
79 | associated with it. The first line is the "status line", which | |
80 | contains a bit (0 or 1 character) saying whether the message has | |
81 | been reformed yet, and a list of the labels attached to this | |
82 | message. Certain labels, called basic labels, are built into | |
83 | Babyl in a fundamental way, and are separated in the status line | |
84 | for convenience of operation. For example, consider the status | |
85 | line: | |
86 | ||
87 | 1, answered,, zval, bug, | |
88 | ||
89 | The 1 means this message has been reformed. This message is | |
90 | labeled "answered", "zval", and "bug". The first, "answered", is | |
91 | a basic label, and the other two are user labels. The basic | |
92 | labels come before the double-comma in the line. Each label is | |
93 | preceded by ", " and followed by ",". (The last basic label is | |
94 | in fact followed by ",,".) If this message had no labels at all, | |
95 | it would look like: | |
96 | ||
97 | 1,, | |
98 | ||
99 | Or, if it had two basic labels, "answered" and "deleted", it | |
100 | would look like: | |
101 | ||
102 | 1, answered, deleted,, zval, bug, | |
103 | ||
104 | The & Label Babyl Message knows which are the basic labels. | |
105 | Currently they are: deleted, unseen, recent, and answered. | |
106 | ||
107 | After the status line comes the original header if any. | |
108 | Following that is the EOOH line, which contains exactly the | |
109 | characters "*** EOOH ***" (which stands for "end of original | |
110 | header"). Note that the original header, if a network format | |
111 | header, includes the trailing newline. And finally, following the | |
112 | EOOH line is the visible message, header and text. For example, | |
113 | here is a complete message section, starting with the message | |
114 | starter, and ending with the terminator: | |
115 | ||
116 | ^_^L | |
117 | 1,, wordab, eccmacs, | |
118 | Date: 11 May 1982 21:40-EDT | |
119 | From: Eugene C. Ciccarelli <ECC at MIT-AI> | |
120 | Subject: notes | |
121 | To: ECC at MIT-AI | |
122 | ||
123 | *** EOOH *** | |
124 | Date: Tuesday, 11 May 1982 21:40-EDT | |
125 | From: Eugene C. Ciccarelli <ECC> | |
126 | To: ECC | |
127 | Re: notes | |
128 | ||
129 | Remember to pickup check at cashier's office, and deposit it | |
130 | soon. Pay rent. | |
131 | ^_ | |
132 | \f | |
133 | ;;; Babyl File BNF: | |
134 | ||
135 | ;;; Overall Babyl file structure: | |
136 | ||
137 | ||
138 | Babyl-File ::= Babyl-Options-Section (Message-Section)* | |
139 | ||
140 | ||
141 | ;;; Babyl Options section: | |
142 | ||
143 | ||
144 | Babyl-Options-Section | |
145 | ::= "BABYL OPTIONS:" newline (Babyl-Option)* Terminator | |
146 | ||
147 | Babyl-Option ::= Option-Name ":" Horiz-Whitespace BOptValue newline | |
148 | ||
149 | BOptValue ::= Number | 1-Line-String | |
150 | ||
151 | ||
152 | ||
153 | ;;; Message section: | |
154 | ||
155 | ||
156 | Message-Section ::= Message-Starter Status-Line Orig-Header | |
157 | EOOH-Line Message Terminator | |
158 | ||
159 | Message-Starter ::= "^L" newline | |
160 | ||
161 | Status-Line ::= Bit-Char "," (Basic-Label)* "," (User-Label)* newline | |
162 | ||
163 | Basic-Label ::= Space BLabel-Name "," | |
164 | ||
165 | User-Label ::= Space ULabel-Name "," | |
166 | ||
167 | EOOH-Line ::= "*** EOOH ***" newline | |
168 | ||
169 | Message ::= Visible-Header Message-Text | |
170 | ||
171 | ||
172 | ;;; Utilities: | |
173 | ||
174 | Terminator ::= "^_" | |
175 | ||
176 | Horiz-Whitespace | |
177 | ::= (Space | Tab)* | |
178 | ||
179 | Bit-Char ::= "0" | "1" |