Best way to halt Java process?
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From: Mike Schilling on 14 Jun 2010 11:21 "Lew" <noone(a)lewscanon.com> wrote in message news:hv41j1$i8s$1(a)news.albasani.net... > If you guys are going to argue, at least pick theses that contradict each > other. For example, pick different numbers for how many angels can dance > on the head of a pin. Angles have the attribute of position but not the attribute of extension, so the answer is "all of them".
From: ilan on 14 Jun 2010 14:33 Lew <noone(a)lewscanon.com> writes: > Tom Anderson wrote: >> Which hinges, really, on recognising that programs are, when you get >> down to brass tacks, meaningless, purely mechanical constructs. As they >> put it in one of their papers (i forget which): >> >> Formal logical proofs, and therefore programs - formal logical proofs >> that particular computations are possible, expressed in a formal system >> called a programming language - are utterly meaningless. To write a >> computer program you have to come to terms with this, to accept that >> whatever you might want the program to mean, the machine will blindly >> follow its meaningless rules and come to some meaningless conclusion. > > When I took mathematical logic at university way back when, they > taught me two aspects of logical system - the formal, mechanical part > to which you refer, and the interpretation. The interpretation is a > very important part of the use of the system, and likewise therefore > with software. > > There is meaning, and it's the meaning we apply when we translate the > formal symbols back to the world of human experience. Yes.. except a computer language has very specific unambiguous effects. Its not like speaking English or Klingon - its like casting a spell that invokes a genie in the machine. With a computer language, especially when you want implementations to be consistent and you want your process to perform what you mean when you incant it from your magic words - having very clearly defined semantics is extremely useful. Syntax is not enough. Ask Mickey Mouse what happened when he got the syntax right but the semantics wrong when he was a magician's apprentice. In general there are three approaches to semantics with computer languages : operational, denotational and axiomatic. I am not sure if there is enough interest to unpack these approaches. Sadly - none of these three approaches has proven truly successful and mostly we (as practitioners, or implementers) attempt to understand the semantics of languages by RTFM; in languages such as English or Klingon. Because English or Klingon allow too much variation of interpretation this of course is far from _reasonable_ or _impenetrable_. Very few languages, Scheme is an exception, have achieved semantic definitions. -- ilAn
From: Joshua Cranmer on 14 Jun 2010 20:03 On 06/14/2010 07:40 AM, Tom Anderson wrote: > On Sun, 13 Jun 2010, Joshua Cranmer wrote: > >> On 06/13/2010 04:58 PM, Tom Anderson wrote: >>> On Sat, 12 Jun 2010, Joshua Cranmer wrote: >>> >>>> 6. Most other errors: miscoded server providers. I'm not entirely sure >>>> why these are errors, but I'm guessing its to force them to be >>>> propagated to the top-level so that people can fix them. >>> >>> Sorry, i have no idea what errors you're talking about here. What do you >>> mean by 'server'? Could you give a couple of examples? >> >> Typo. It's supposed to be "service" providers. > > Okay, cool. I still don't get it, though - what errors are thrown by > misconfigured service providers? Do you mean things like LinkageError > and so on thrown when some service provider jar doesn't match up with > the rest of the environment? java.xml.parsers.FactoryConfigurationError: Thrown when a problem with configuration with the Parser Factories exists. This error will typically be thrown when the class of a parser factory specified in the system properties cannot be found or instantiated. -- Beware of bugs in the above code; I have only proved it correct, not tried it. -- Donald E. Knuth
From: Lew on 14 Jun 2010 20:22 Lew writes: >> When I took mathematical logic at university way back when, they >> taught me two aspects of logical system - the formal, mechanical part >> to which you refer, and the interpretation. The interpretation is a >> very important part of the use of the system, and likewise therefore >> with software. >> >> There is meaning, and it's the meaning we apply when we translate the >> formal symbols back to the world of human experience. ilan wrote: > Yes.. except a computer language has very specific unambiguous > effects. Its not like speaking English or Klingon - its like casting a > spell that invokes a genie in the machine. "Except"? Are you implying that formal logic has non-specific or ambiguous effects? > With a computer language, especially when you want implementations to be > consistent and you want your process to perform what you mean when you > incant it from your magic words - having very clearly defined semantics > is extremely useful. Syntax is not enough. Ask Mickey Mouse what > happened when he got the syntax right but the semantics wrong when he > was a magician's apprentice. "Mickey Mouse" - pfaugh! /The Sorcerer's Apprentice/ was around for quite a while before Disney made a hack of it. -- Lew
From: Lew on 14 Jun 2010 20:29
On 06/14/2010 11:21 AM, > "Lew" <noone(a)lewscanon.com> wrote in message > news:hv41j1$i8s$1(a)news.albasani.net... >> If you guys are going to argue, at least pick theses that contradict >> each other. For example, pick different numbers for how many angels >> can dance on the head of a pin. Mike Schilling wrote: > Angles have the attribute of position but not the attribute of > extension, so the answer is "all of them". That was a typo, right? You intended "angels" for "angles", I'm assuming. My point was that the discussion of what constitutes a "reasonable" program in this thread had devolved to the level at which theologians of a few centuries ago stood when they debated how many angels could dance on the head of a pin. Each proponent invented their own idea of the attributes of angels (such as "position but not extension" - your evidence for that? Hm?) and argued based on their particular fantasy definitions and axioms. And the head is the opposite end from the point, btw. As anyone should know. <http://en.wikipedia.org/wiki/Pin> -- Lew |