No relation to the sports channel.

  • 11 Posts
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Joined 1 year ago
Cake day: June 9th, 2023
  • fubo@lemmy.worldtoProgrammer Humor@lemmy.ml•Oh boy what a beautiful regex. I'm sure it does something logical and easy to understand.
    10·
    17 days ago

    Regex is good for a few very specific things, and sysadmins used to use it for goddamn everything. If all your server logs are in lightly-structured text files on a small number of servers, being able to improvise regex is damn useful for tracking down server problems. Just write a shell loop that spawns an ssh logging into each server and running grep over the log files, to look for that weird error.

    These days, if you need to crunch production server logs you probably need to improvise in SQL and jq and protobufs or systemd assmonkery or something.

    But if you actually need a parser, for goodness sake use a parser combinator toolkit, don’t roll your own, especially not with regex. Describing your input language in plain Haskell is much nicer than kludging it.

    (This is the “totally serious software engineering advice” forum, right?)

  • fubo@lemmy.worldtoProgrammer Humor@lemmy.ml•Oh boy what a beautiful regex. I'm sure it does something logical and easy to understand.
    112·
    16 days ago

    The answer given in the spoiler tag is not quite correct!

    Test case

    According to the spoiler, this shouldn’t match “abab”, but it does.

    Corrected regex

    This will match what the spoiler says: ^.?$|^((.)\2+?)\1+$

    Full workup

    Any Perl-compatible regex can be parsed into a syntax tree using the Common Lisp package CL-PPCRE. So if you already know Common Lisp, you don’t need to learn regex syntax too!

    So let’s put the original regex into CL-PPCRE’s parser. (Note, we have to add a backslash to escape the backslash in the string.) The parser will turn the regex notation into a nice pretty S-expression.

    > (cl-ppcre:parse-string "^.?$|^(..+?)\\1+$")
(:ALTERNATION
 (:SEQUENCE :START-ANCHOR (:GREEDY-REPETITION 0 1 :EVERYTHING) :END-ANCHOR)
 (:SEQUENCE :START-ANCHOR
  (:REGISTER
   (:SEQUENCE :EVERYTHING (:NON-GREEDY-REPETITION 1 NIL :EVERYTHING)))
  (:GREEDY-REPETITION 1 NIL (:BACK-REFERENCE 1)) :END-ANCHOR))

    At which point we can tell it’s tricky because there’s a capturing register using a non-greedy repetition. (That’s the \1 and the +? in the original.)

    The top level is an alternation (the | in the original) and the first branch is pretty simple: it’s just zero or one of any character.

    The second branch is the fun one. It’s looking for two or more repetitions of the captured group, which is itself two or more characters. So, for instance, “aaaa”, or “abcabc”, or “abbaabba”, but not “aaaaa” or “abba”.

    So strings that this matches will be of non-prime length: zero, one, or a multiple of two numbers 2 or greater.

    But it is not true that it matches only “any character repeated a non-prime number of times” because it also matches composite-length sequences formed by repeating a string of different characters, like “abcabc”.

    If we actually want what the spoiler says — only non-prime repetitions of a single character — then we need to use a second capturing register inside the first. This gives us:

    ^.?$|^((.)\2+?)\1+$.

    Specifically, this replaces (..+?) with ((.)\2+?). The \2 matches the character captured by (.), so the whole regex now needs to see the same character throughout.

  • fubo@lemmy.worldtopolitics @lemmy.world•Opinion | How the DOJ’s major takedown of a neo-Nazi group contradicts MAGA’s worldview
    17·
    1 month ago

    I thought everyone knew meth comes from Nazis. Like, not only have white-supremacist dirtbags been big in the US meth trade since forever, but the actual historical German Nazis were literally on meth. Here’s Wikipedia —

    From 1938, methamphetamine was marketed on a large scale in Germany as a nonprescription drug under the brand name Pervitin, produced by the Berlin-based Temmler pharmaceutical company. It was used by all branches of the combined armed forces of the Third Reich, for its stimulant effects and to induce extended wakefulness. Pervitin became colloquially known among the German troops as “Stuka-Tablets” (Stuka-Tabletten) and “Herman-Göring-Pills” (Hermann-Göring-Pillen), as a snide allusion to Göring’s widely-known addiction to drugs.

  • fubo@lemmy.worldtoWorld News@lemmy.ml•Majority of Americans and Europeans support ending the war in Ukraine
    01·
    5 months ago

    I’m for ending the war through a unilateral surrender of Russian forces and the trial of Mr Putin for crimes against humanity. However, my opinion doesn’t have a lot of influence over whether that happens.

    Similarly, I’m for ending the war in Gaza through the voluntary disarmament of Hamas, the repudiation of terrorism as a way of life, the handover of illegal settlements to displaced Palestinian Arab civilians, and the prosecution of Netanyahu for treason and war crimes. But I don’t expect to get to make that decision either.

  • fubo@lemmy.worldtoAsklemmy@lemmy.ml•What is the most unhinged conspiracy theory?
    10·
    6 months ago

    Microsoft, the state of South Dakota, and the Freemasons have been infiltrated by the Unified Buttjones Imperial Court (UBIC), formed in 1834 by the merger of the Imperial Buttjones Society and the All-Ireland Industrial Arsing Federation. UBIC agents camouflage themselves as janitors, assistant product managers, or beagles, and spread an invisible green slime over toilet seats to infect the minds of their targets. Through this mental infiltration, they obtain control over the vazween or pony-flavored sector of the human soul, creating Inter-Vazween Buttjones Networks (IVBN) through repeated application of the Greater Invoking Pentacle of Pony Erotic Revelation (GIPPER). Using an apparatus constructed from illegal immigrants, UBIC uses the IVBN and GIPPER to insert bugs into Windows, Masonic initiations, and the Lewis & Clark State Recreation Area. Anyone who denies this obvious truth is a buttjones.

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