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EDIT: I decided to ship it as is
I messed up, I think.
I had my GLR parser generator all ready to go, so I want it to demo something that only an advanced parser like a GLR parser could parse (at least without handwritten parts, unlike Parsley)
I loaded up my C# subset (Slang) expression grammar and started to port it from parsley to glory which means removing the handwritten components and replacing them with the sort of BNF/XBNF constructs that Parsley couldn't parse.
Here's the problem: GLR grammars are never rejected. No matter how dodgy the grammar you give it is, it will find a way to accept it and parse it, even if what it returned might not be what you intended (as happens with complicated things)
That might not seem like a problem until you're trying to actually build a valid grammar. GLR will accept anything "valid" or not. All "invalid" means to GLR is that your parse trees won't come back in the form you expected them to.
Detecting whether a grammar is globally ambiguous is mathematically impossible (it has been proven undecidable)
So the next best thing would be to do analysis on it by trying to generate a less powerful parser using something like LL(k/*) but that doesn't quite work since LL only works on grammars that are not left recursive. Even if I knew how to implement LL(k/*) (I don't). Even if that wasn't an issue it still doesn't work because there's still a set of grammars GLR parses that LL can't - ambiguous grammars
It's a logic problem. I want it to reject invalid grammars but it can't know what "invalid" means unless I tell it, which is what the grammar is for in the first place!
The only thing i can think of is having a way to specify in the grammar that a certain construct should or should *not* be ambiguous but I am almost positive that will not work as I don't think it's mathematically possible to detect all local ambiguities either.
Frankly, GLR is *too* expressive. I just don't know what I can do about that, but it makes constructing accurate grammars extremely difficult.
Other people have built GLR parsers, so there might be a clever solution somewhere for this, but I'm not likely to google the problem and find much - GLR is rare, aside from Bison, the only "mainstream" parser offering that includes it, and it was only added later on.
If I had thought far enough ahead I would have researched that up front, but now I'm wondering if I should ship like this, or hold off until I can find a better way. 
Real programmers use butterflies
modified 22-Feb-20 10:27am.
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honey the codewitch wrote: I'm wondering if I should ship like this, or hold off until I can find a better way.
EA games would have shipped a couple of months ago and provide an expensive DLC to fix it.
Apple would call it a battery saving feature and ship a new version of the hardware.
Samsung would call it a hand warmer.
Corel wouldn't even ask themselves the question ... 
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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Hahaha it's funny because it's true!
Real programmers use butterflies
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you forgot microsoft:
they would ship, release most of the fix incrementally over a number of 'updates,' then lose interest.
(queue the haters ...c'mon, y'all knew I couldn't resist another dig at les miserablesoft)
after many otherwise intelligent sounding suggestions that achieved nothing the nice folks at Technet said the only solution was to low level format my hard disk then reinstall my signature. Sadly, this still didn't fix the issue!
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lopatir wrote: queue the haters
"Cue", not "queue".
That'll be 50 cents.
I wanna be a eunuchs developer! Pass me a bread knife!
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I am not sure I follow you here. Are you saying that a well designed GLR parser accepts any input? So, if V is the set of terminals, your generated parser will accept V+ ?
It seems to me that there are easier ways to accept "any" input string
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It will not simply accept V+
I'm saying it accepts any grammar, not any input (maybe I misspoke somewhere above? i haven't looked)
The inputs must conform in some way to the grammar provided, but the grammar can be ambiguous in any way.
Real programmers use butterflies
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You're simply confirming that (good) design is an iterative process. More bangs too.
It was only in wine that he laid down no limit for himself, but he did not allow himself to be confused by it.
― Confucian Analects: Rules of Confucius about his food
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Is it just me or has the latest update to VS2019 made it a bit of an unstable mess? At least once a day it locks up and rolls over with all 4 paws in the air and restarts, losing whatever I had unsaved.
I feel like I'm back in 1996, hitting Ctrl+S every 3 carriage returns
cheers
Chris Maunder
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Chris Maunder wrote: I feel like I'm back in 1996, hitting Ctrl+S every 3 carriage returns
ahh, life on the bleeding edge.... I DONT miss those days at all.
ON ERROR GOTO RULE 1
RULE 1 to 100: You will only update when I know it's safe and only when I say to do so.
RULE 101+: see: (rule # MODULO 100) + 1
GOTO RULE 1
You have auto-updates on ???
after many otherwise intelligent sounding suggestions that achieved nothing the nice folks at Technet said the only solution was to low level format my hard disk then reinstall my signature. Sadly, this still didn't fix the issue!
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lopatir wrote: You have auto-updates on
For VS? No. (didn't know that was even a thing)
cheers
Chris Maunder
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I'm currently using Microsoft VS2019, smoothly, with no crashes. Probably, you'll need to completely reinstall VS2019 on your development machine. Beforehand, I recommend creating a complete VS2019 installation layout on your local drive and then use the offline installer. Here's how: Create an offline installation - Visual Studio | Microsoft Docs[^].
Simply, re-install VS2019 without any add-ins such as Intel Parallel Studio XE integration or whatsoever. And, then, try using it. Will it crash again? Specifically, for some time ago, I've experienced a problem using Intel Compiler 2019 XE integrated with VS2019. A complete re-install of Windows from my system drive backup helped to solve the following problem.
Also, this could be also a hardware problem with system memory (RAM) on your development machine. In this case, I also recommend checking your PC's system memory with memtestx86+.
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You mistake me for someone far less lazy than I am 
(but thanks for the tips)
cheers
Chris Maunder
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You're very welcome. 
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Have you tried changing your desktop wallpaper?
I wanna be a eunuchs developer! Pass me a bread knife!
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No, no - it's the icons you have to change ...
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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Either that or hire a specialist consultant to change both.
I wanna be a eunuchs developer! Pass me a bread knife!
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can not rush in like that! first need business analyst to tell you what you need consultant for.
after many otherwise intelligent sounding suggestions that achieved nothing the nice folks at Technet said the only solution was to low level format my hard disk then reinstall my signature. Sadly, this still didn't fix the issue!
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No, no - first comes the Business Risk Assessment.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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For that you need to hire a consultant.
Incidentally, does anyone know of a message board that specialises in giving advice on repairing water buckets?
I wanna be a eunuchs developer! Pass me a bread knife!
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YouTube[^] has a tutorial.
"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!
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Perfect!
Just what I was looking for!
I wanna be a eunuchs developer! Pass me a bread knife!
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Sounds like my current contract 😱
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Not only that: I ensured my machine was plugged in, I checked my internet connection, and I also turned off the machine, waited 30 seconds, and turned it back on. I've essentially run the full suite of advanced help desk techniques. And still it crashes once a day!
Doomed, I am.
cheers
Chris Maunder
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Hmm.
It looks like you forgot to implement the "shake your mouse about" method.
I wanna be a eunuchs developer! Pass me a bread knife!
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