pi.conf

#@version: 3.141592647
@version: 3.14

@include "scl.conf"

#This is somewhat barbaric and overkill, but also an experimental playground so do not judge me.
block root syslog-ng-ctl(context()) {
    block `context` syslog-ng-ctl-`context`(command(), ...) {
       destination { unix-stream("`syslog-ng-root`/var/syslog-ng.ctl" template("`command`\n") `__VARARGS__`); };
    }
};

syslog-ng-ctl(context(log));
syslog-ng-ctl(context(root));


block root pi(iteration(), digits()) {

options { time-reopen(1); };

log {
   source { internal(); };

   filter { message("syslog-ng starting up"); };

   rewrite { set("1" value("i")); };
   rewrite { set("1" value("n")); };
   rewrite { set("-1" value("direction")); };
   rewrite { set("$(* 3 `digits`)" value("pi")); };

   destination {
        unix-stream("/tmp/loop" persist-name("start") template("$(format-ewmm)\n"));
   };
};


log {

    source  { unix-stream("/tmp/loop" flags(no-parse)); };
        parser  { syslog-parser(flags(syslog-protocol)); }; # For some reason this is needed for ewmm-parser()
        parser  { ewmm-parser(); };

        rewrite { set("$(* ${direction} -1)" value("direction")); };

        rewrite { set("$(+ ${i} 1)" value("i")); };

        rewrite { set("$(+ ${n} 2)" value("n")); };

        rewrite { set("$(+ ${n} 1)" value("n_p1")); };
        rewrite { set("$(- ${n} 1)" value("n_m1")); };
        rewrite { set("$(* ${n_p1} ${n_m1})" value("n_pm")); };

        rewrite { set("$(* ${n_pm} ${n})" value("denominator")); };

        rewrite { set("$(* 4 `digits`)" value("nominator")); };
        rewrite { set("$(/ ${nominator} ${denominator})" value("abs_diverge")); };

        rewrite { set("$(* ${direction} ${abs_diverge})" value("divereged")); };

        rewrite { set("$(+ ${pi} ${divereged})" value("pi")); };
      
    if ("${i}" <= "`iteration`") {

    destination { file("/dev/stdout" template("iteration=${i} pi ~ ${pi}\n"));
                  #file("/dev/stdout" template("$(format-welf --scope nv-pairs)\n")); #debug option
                  unix-stream("/tmp/loop" template("$(format-ewmm)\n")); };
    }
    else {
      syslog-ng-ctl-log(command("STOP"));
    };
}
};

pi(iteration(100), digits(1000000000));