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Text File | 1998-10-28 | 11.5 KB | 332 lines

/xlv1/freeware/1998.Oct/procmail/3.11pre7/procmail-3.11pre7.diffbuild/new PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) BBBBuuuuGGGGlllleeeessssssss ((((1111999999994444////11110000////00007777)))) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) NNNNAAAAMMMMEEEE procmailsc - procmail weighted scoring techique SSSSYYYYNNNNOOOOPPPPSSSSIIIISSSS [****] wwww^^^^xxxx ccccoooonnnnddddiiiittttiiiioooonnnn DDDDEEEESSSSCCCCRRRRIIIIPPPPTTTTIIIIOOOONNNN In addition to the traditional true or false conditions you can specify on a recipe, you can use a weighted scoring technique to decide if a certain recipe matches or not. When weighted scoring is used in a recipe, then the final score for that recipe must be positive for it to match. A certain condition can contribute to the score if you allocate it a `weight' (wwww) and an `exponent' (xxxx). You do this by preceding the condition (on the same line) with: wwww^^^^xxxx Whereas both wwww and xxxx are real numbers between -2147483647.0 and 2147483647.0. WWWWeeeeiiiigggghhhhtttteeeedddd rrrreeeegggguuuullllaaaarrrr eeeexxxxpppprrrreeeessssssssiiiioooonnnn ccccoooonnnnddddiiiittttiiiioooonnnnssss The first time the regular expression is found, it will add _w to the score. The second time it is found, _w*_x will be added. The third time it is found, _w*_x*_x will be added. The fourth time _w*_x*_x*_x will be added. And so forth. This can be described by the following concise formula: n n k-1 x - 1 w * Sum x = w * ------- k=1 x - 1 It represents the total added score for this condition if nnnn matches are found. Note that the following case distinctions can be made: x=0 Only the first match will contribute w to the score. Any subsequent matches are ignored. x=1 Every match will contribute the same w to the score. The score grows linearly with the number of matches found. Page 1 (printed 8/25/98) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) BBBBuuuuGGGGlllleeeessssssss ((((1111999999994444////11110000////00007777)))) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) 0<x<1 Every match will contribute less to the score than the previous one. The score will asymptotically approach a certain value (see the NNNNOOOOTTTTEEEESSSS section below). 1<x Every match will contribute more to the score than the previous one. The score will grow exponentionally. x<0 Can be utilised to favour odd or even number of matches. If the regular expression is negated (i.e. matches if it isn't found), then nnnn obviously can either be zero or one. WWWWeeeeiiiigggghhhhtttteeeedddd pppprrrrooooggggrrrraaaammmm ccccoooonnnnddddiiiittttiiiioooonnnnssss If the program returns an exitcode of EXIT_SUCCESS (=0), then the total added score will be wwww. If it returns any other exitcode (indicating failure), the total added score will be xxxx. If the exitcode of the program is negated, then, the exitcode will be considered as if it were a virtual number of matches. Calculation of the added score then proceeds as if it had been a normal regular expression with nnnn====````eeeexxxxiiiittttccccooooddddeeee'''' matches. WWWWeeeeiiiigggghhhhtttteeeedddd lllleeeennnnggggtttthhhh ccccoooonnnnddddiiiittttiiiioooonnnnssss If the length of the actual mail is MMMM then: * w^x > L will generate an additional score of: 1 / M \ w * | --- | \ L / And: * w^x < L will generate an additional score of: 1 / L \ w * | --- | \ M / In both cases, if L=M, this will add w to the score. In the former case however, larger mails will be favoured, in the Page 2 (printed 8/25/98) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) BBBBuuuuGGGGlllleeeessssssss ((((1111999999994444////11110000////00007777)))) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) latter case, smaller mails will be favoured. Although x can be varied to fine-tune the steepness of the function, typical usage sets x=1. MMMMIIIISSSSCCCCEEEELLLLLLLLAAAANNNNEEEEOOOOUUUUSSSS You can query the final score of all the conditions on a recipe from the environment variable $$$$====. This variable is set _e_v_e_r_y time just after procmail has parsed all conditions on a recipe (even if the recipe is not being executed). EEEEXXXXAAAAMMMMPPPPLLLLEEEESSSS The following recipe will ditch all mails having more than 150 lines in the body. The first condition contains an empty regular expression which, because it always matches, is used to give our score a negative offset. The second condition then matches every line in the mail, and consumes up the previous negative offset we gave (one point per line). In the end, the score will only be positive if the mail contained more than 150 lines. :0 Bh * -150^0 * 1^1 ^.*$ /dev/null Suppose you have a priority folder which you always read first. The next recipe picks out the priority mail and files them in this special folder. The first condition is a regular one, i.e. it doesn't contribute to the score, but simply has to be satisfied. The other conditions describe things like: john and claire usually have something important to say, meetings are usually important, replies are favoured a bit, mails about Elvis (this is merely an example :-) are favoured (the more he is mentioned, the more the mail is favoured, but the maximum extra score due to Elvis will be 4000, no matter how often he is mentioned), lots of quoted lines are disliked, smileys are appreciated (the score for those will reach a maximum of 3500), those three people usually don't send interesting mails, the mails should preferably be small (e.g. 2000 bytes long mails will score -100, 4000 bytes long mails do -800). As you see, if some of the uninteresting people send mail, then the mail still has a chance of landing in the priority folder, e.g. if it is about a meeting, or if it contains at least two smileys. Page 3 (printed 8/25/98) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) BBBBuuuuGGGGlllleeeessssssss ((((1111999999994444////11110000////00007777)))) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) :0 HB * !^Precedence:.*(junk|bulk) * 2000^0 ^From:.*(john@home|claire@work) * 2000^0 ^Subject:.*meeting * 300^0 ^Subject:.*Re: * 1000^.75 elvis|presley * -100^1 ^> * 350^.9 :-\) * -500^0 ^From:.*(boss|jane|henry)@work * -100^3 > 2000 priority_folder If you are subscribed to a mailinglist, and just would like to read the quality mails, then the following recipes could do the trick. First we make sure that the mail is coming from the mailinglist. Then we check if it is from certain persons of whom we value the opinion, or about a subject we absolutely want to know everything about. If it is, file it. Otherwise, check if the ratio of quoted lines to original lines is at most 1:2. If it exceeds that, ditch the mail. Everything that survived the previous test, is filed. :0 ^From mailinglist-request@some.where { :0: * ^(From:.*(paula|bill)|Subject:.*skiing) mailinglist :0 Bh * 20^1 ^> * -10^1 ^[^>] /dev/null :0: mailinglist } For further examples you should look in the pppprrrrooooccccmmmmaaaaiiiilllleeeexxxx(5) man page. CCCCAAAAVVVVEEEEAAAATTTTSSSS Because this speeds up the search by an order of magnitude, the procmail internal egrep will always search for the leftmost _s_h_o_r_t_e_s_t match, unless it is determining what to assign to MMMMAAAATTTTCCCCHHHH, in which case it searches the leftmost _l_o_n_g_e_s_t match. E.g. for the leftmost _s_h_o_r_t_e_s_t match, by itself, the regular expression: Page 4 (printed 8/25/98) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) BBBBuuuuGGGGlllleeeessssssss ((((1111999999994444////11110000////00007777)))) PPPPRRRROOOOCCCCMMMMAAAAIIIILLLLSSSSCCCC((((5555)))) ....**** will always match a zero length string at the same spot. ....++++ will always match one character (except newlines of course). SSSSEEEEEEEE AAAALLLLSSSSOOOO pppprrrrooooccccmmmmaaaaiiiillll(1), pppprrrrooooccccmmmmaaaaiiiillllrrrrcccc(5), pppprrrrooooccccmmmmaaaaiiiilllleeeexxxx(5), sssshhhh(1), ccccsssshhhh(1), eeeeggggrrrreeeepppp(1), ggggrrrreeeepppp(1), BBBBUUUUGGGGSSSS If, in a length condition, you specify an xxxx that causes an overflow, procmail is at the mercy of the ppppoooowwww(3) function in your mathematical library. Floating point numbers in `engineering' format (e.g. 12e5) are not accepted. MMMMIIIISSSSCCCCEEEELLLLLLLLAAAANNNNEEEEOOOOUUUUSSSS As soon as `plus infinity' (2147483647) is reached, any sub- sequent _w_e_i_g_h_t_e_d conditions will simply be skipped. As soon as `minus infinity' (-2147483647) is reached, the condition will be considered as `no match' and the recipe will terminate early. NNNNOOOOTTTTEEEESSSS If in a regular expression weighted formula 0000<<<<xxxx<<<<1111, the total added score for this condition will asymptotically approach: w ------- 1 - x In order to reach half the maximum value you need - ln 2 n = -------- ln x matches. AAAAUUUUTTTTHHHHOOOORRRR Stephen R. van den Berg <srb@cuci.nl> Page 5 (printed 8/25/98)