1Format of Version 5 Babyl Files: 2 3Warning: 4 5 This was written Tuesday, 12 April 1983 (by Eugene Ciccarelli), 6based on looking at a particular Babyl file and recalling various 7issues. Therefore it is not guaranteed to be complete, but it is a 8start, and I will try to point the reader to various Babyl functions 9that will serve to clarify certain format questions. 10 11 Also note that this file will not contain control-characters, 12but instead have two-character sequences starting with Uparrow. 13Unless otherwise stated, an Uparrow <character> is to be read as 14Control-<character>, e.g. ^L is a Control-L. 15 16Versions: 17 18 First, note that each Babyl file contains in its BABYL OPTIONS 19section the version for the Babyl file format. In principle, the 20format can be changed in any way as long as we increment the format 21version number; then programs can support both old and new formats. 22 23 In practice, version 5 is the only format version used, and the 24previous versions have been obsolete for so long that Emacs does not 25support them. 26 27 28Overall Babyl File Structure: 29 30 A Babyl file consists of a BABYL OPTIONS section followed by 310 or more message sections. The BABYL OPTIONS section starts 32with the line "BABYL OPTIONS:". Message sections start with 33Control-Underscore Control-L Newline. Each section ends 34with a Control-Underscore. (That is also the first character 35of the starter for the next section, if any.) Thus, a three 36message Babyl file looks like: 37 38BABYL 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 49file -- the file may end with the final ^_ or it may have some 50whitespace, e.g. a newline, after it. 51 52 53The BABYL OPTIONS Section: 54 55 Each Babyl option is specified on one line (thus restricting 56string values these options can currently have). Values are 57either numbers or strings. The format is name, colon, and the 58value, with whitespace after the colon ignored, e.g.: 59 60Mail: ~/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 72 73Message Sections: 74 75 A message section contains one message and information 76associated with it. The first line is the "status line", which 77contains a bit (0 or 1 character) saying whether the message has 78been reformed yet, and a list of the labels attached to this 79message. Certain labels, called basic labels, are built into 80Babyl in a fundamental way, and are separated in the status line 81for convenience of operation. For example, consider the status 82line: 83 841, answered,, zval, bug, 85 86 The 1 means this message has been reformed. This message is 87labeled "answered", "zval", and "bug". The first, "answered", is 88a basic label, and the other two are user labels. The basic 89labels come before the double-comma in the line. Each label is 90preceded by ", " and followed by ",". (The last basic label is 91in fact followed by ",,".) If this message had no labels at all, 92it would look like: 93 941,, 95 96 Or, if it had two basic labels, "answered" and "deleted", it 97would look like: 98 991, answered, deleted,, zval, bug, 100 101 The & Label Babyl Message knows which are the basic labels. 102Currently they are: deleted, unseen, recent, and answered. 103 104 After the status line comes the original header if any. 105Following that is the EOOH line, which contains exactly the 106characters "*** EOOH ***" (which stands for "end of original 107header"). Note that the original header, if a network format 108header, includes the trailing newline. And finally, following the 109EOOH line is the visible message, header and text. For example, 110here is a complete message section, starting with the message 111starter, and ending with the terminator: 112 113^_^L 1141,, wordab, eccmacs, 115Date: 11 May 1982 21:40-EDT 116From: Eugene C. Ciccarelli <ECC at MIT-AI> 117Subject: notes 118To: ECC at MIT-AI 119 120*** EOOH *** 121Date: Tuesday, 11 May 1982 21:40-EDT 122From: Eugene C. Ciccarelli <ECC> 123To: ECC 124Re: notes 125 126Remember to pickup check at cashier's office, and deposit it 127soon. Pay rent. 128^_ 129 130;;; Babyl File BNF: 131 132;;; Overall Babyl file structure: 133 134 135Babyl-File ::= Babyl-Options-Section (Message-Section)* 136 137 138;;; Babyl Options section: 139 140 141Babyl-Options-Section 142 ::= "BABYL OPTIONS:" newline (Babyl-Option)* Terminator 143 144Babyl-Option ::= Option-Name ":" Horiz-Whitespace BOptValue newline 145 146BOptValue ::= Number | 1-Line-String 147 148 149 150;;; Message section: 151 152 153Message-Section ::= Message-Starter Status-Line Orig-Header 154 EOOH-Line Message Terminator 155 156Message-Starter ::= "^L" newline 157 158Status-Line ::= Bit-Char "," (Basic-Label)* "," (User-Label)* newline 159 160Basic-Label ::= Space BLabel-Name "," 161 162User-Label ::= Space ULabel-Name "," 163 164EOOH-Line ::= "*** EOOH ***" newline 165 166Message ::= Visible-Header Message-Text 167 168 169;;; Utilities: 170 171Terminator ::= "^_" 172 173Horiz-Whitespace 174 ::= (Space | Tab)* 175 176Bit-Char ::= "0" | "1" 177