# IRC log for #marpa, 2015-09-26

All times shown according to UTC.

Time Nick Message
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02:11 Idiosyncrat Those taking an advanced peek at the new paper may notice that it now presents Earley items in terms of
02:11 Idiosyncrat top-down causes and bottom-up causes.
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02:14 Idiosyncrat I found it a very natural approach -- it helps me in thinking out things about Earley's algorithm ...
02:15 Idiosyncrat and it has the very grate advantage of explaining exactly why Earley's really cannot be classified as a top-down or bottom-up parsing method.
02:15 Idiosyncrat s/grate/great/
02:59 ceridwen Am I the only one who doesn't find the top-down/bottom-up classification that useful?
06:43 Idiosyncrat ceridwen: Well, it's useful when it's useful :-)
06:44 Idiosyncrat It's not a bad way to understand the difference between, on one hand,
06:44 Idiosyncrat LALR, yacc, bison, LR, etc. and ...
06:45 Idiosyncrat PEG, recursive descent, ANTLR, on the other.
06:46 Idiosyncrat But I did find it annoying in the first days of Marpa, because folks would classify Marpa and then say, "and so it cannot do XYZ well"
06:46 Idiosyncrat Peculiar thing is, depending on the preferences, they'd say Marpa cannot do XYZ, because it is top-down ...
06:47 Idiosyncrat or else, if they liked ABC, they'd say Marpa cannot do it because it is bottom-up. :-)
06:49 Idiosyncrat If you insist every creature is either a fish or a land animal, you're going to have trouble understanding birds. :-)
06:49 Idiosyncrat Good night!
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20:54 MerittClarksdale It is a work of pure genius and of great utility
20:55 Idiosyncrat Thank you
21:26 Idiosyncrat Re CWeb -- yes, I knew that to keep track of all that mathematical C code, I'd need literate programming ...
21:26 Idiosyncrat and that it would have to be math-aware, so that seemed to point to Knuth's CWeb.
21:27 Idiosyncrat CWeb is a bear to install and use, but it did do the job.
21:27 Idiosyncrat Knuth turns all his stuff into books and articles, and I had visions of doing the same with the Libmarpa code, ...
21:28 Idiosyncrat but what's out there is actually just extensive notes to myself on matters of detail.
21:34 Idiosyncrat For some reason, literate programming just does not catch on.
21:34 Idiosyncrat Perhaps because there's a big immediate payoff to just skipping it, ...
21:35 Idiosyncrat while all the benefits tend to be far down the road.
21:35 Idiosyncrat And CWeb is just not user-friendly.
21:36 Idiosyncrat If you're Don Knuth, and it means you can just ship the result off to Prentice-Hall and it's definitely a book and quite possibly a classic, ...
21:36 Idiosyncrat then it makes sense.
21:37 Idiosyncrat If you're anybody else but Don Knuth, a lot of the effort is for something that's just not something you need.
21:38 Idiosyncrat I encountered it a bit many years ago.
21:39 Idiosyncrat I'm told it's very much alive in certain circles, but I don't see it much any more.
21:40 Idiosyncrat It was designed IIRC before the first parser was published, which does not make for elegant syntax
21:41 Idiosyncrat Yes, it appeared in 1959 and the first paper on parsing theory came out in 1961.
21:42 Idiosyncrat When I was in grad school, it was the fashion (frankly) to sneer at COBOL, which was then perhaps 80% of the job market.
21:42 Idiosyncrat But it was a pioneer in portable programming.
21:44 Idiosyncrat Nowadays I think it's become a subculture.  I'm told there's an astounding number of lines of *new* COBOL being produced each day.
21:44 Idiosyncrat And it's running in important places.
21:45 Idiosyncrat But it's almost like that's happening on another planet.
21:50 Idiosyncrat True, but C is used far more in networking and systems code ...
21:50 Idiosyncrat it's sort of like outfielders -- the good ones have more scored errors than the bad ones.
21:51 Idiosyncrat Because if you never catch up with the baseball, you aren't going to drop it. :-)
21:52 Idiosyncrat C and UNIX were designed at a point where security issues could be literally resolved by calling people's moms.
21:52 Idiosyncrat That is, they were in use at universities, and not really expected to see wider use.
21:53 Idiosyncrat There were troublesome users among the undergraduates, ...
21:53 Idiosyncrat and if things got really out of hand, it became a matter of school discipline, and their parents got involved.
21:55 Idiosyncrat That they now have to face a world where there are hacker institutes supported by governments, where smart highly-funded motivated folks ...
21:55 Idiosyncrat are dreaming up ways of finding holes in them ...
21:55 Idiosyncrat and Dennis and Ken I don't believe ever imagined such a thing.
21:57 Idiosyncrat If I'm not mistaken, if it's a COBOL app (that is, not bit and pointer-twiddling), then COBOL runs as fast or faster ...
21:58 Idiosyncrat There are some screamingly fast COBOL compilers out there I think.
22:01 Idiosyncrat Actually I'm told that in number-crunching COBOL and Fortran *beat* C, because of C's capabilities in terms of pointer-twiddling ...
22:01 Idiosyncrat That is in COBOL and Fortran, the optimizer can be sure of what code does and does not refer to a variable, and a lot of optimizations are safe, ...
22:02 Idiosyncrat which are just not safe in C, because some of the references in C may be through who-knows-what indirection.
22:03 Idiosyncrat And the optimizers can use that to their advantage.
22:04 Idiosyncrat AFK for a bit -- nice to meet you!