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