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15-Jan-20 9:31

I'm making a little virtual machine to run backtracking regular expressions. It only has a few opcodes but it's all I need for matching.

enum Opcode
{
	Nop = 0,
	Char,
	Range,
	Match,
	Jmp,
	Split,
	Any,
	Save,
}

This is such a different approach than my non-backtracking expressions, which would basically be a subset of this machine with ... 2? instructions I think but it isn't implemented that way at all.

This is pretty cool. I can add regular expression features to the core runner by adding opcodes, but for the most part, I shouldn't need to add to these.

And they should be pretty easy to emit to either IL (as compiled) or C# (table driven) instructions

My instruction pointer is basically a List<Instruction> in tandem with an integer index. If I were doing it in C or C++ it would be an actual pointer, but I think a side effect of this is mine in some ways is a bit more efficient in that it doesn't need as many heap allocs as doing this in C in the most obvious way would, simply because of the way I've organized it.

I'm a long way from an article yet. I'm not even done with my machine compiler yet, but I'm still excited about it. This is cool stuff. Smile | :)

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Eddy Vluggen15-Jan-20 11:56

15-Jan-20 11:56

Missing a few there.

honey the codewitch wrote:
enum Opcode
{
Nop = 0,
Char,
Range,
Match,
Jmp,
Split,
Any,
Save,
}

enum {
EFileNotFound,
ECListCtrl,
EPizzaPineapple,
EVB6NotSupportedGoF(ault)Yourself
}

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Greg Utas15-Jan-20 12:04

15-Jan-20 12:04

You're wasting your time because nobody but you understands regular expressions. Smile | :)

Now that Visual Studio has kowtowed to regular expressions, I find searching for non-trivial things to be a deep PitA. Its "help" on the topic just blows. Someday I'll make time to find decent documentation on the subject. Until then, I'm sometimes reduced to a two-pass approach, of finding too much and then searching for certain substrings within the results window.

honey the codewitch15-Jan-20 13:41

15-Jan-20 13:41

Yeah but it's not just regex. It's the little machine that's cool.

For example, matching foo|bar

L0000: split L0001, L0005
L0001: char f
L0002: char o
L0003: char o
L0004: jmp L0008
L0005: char b
L0006: char a
L0007: char r
L0008: match

Real programmers use butterflies

Eddy Vluggen15-Jan-20 13:54

15-Jan-20 13:54

Is it a coincidence you lot like to number your lines like basic-programmers?

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Greg Utas15-Jan-20 14:03

15-Jan-20 14:03

But isn't it past your bedtime?!

Eddy Vluggen15-Jan-20 14:25

15-Jan-20 14:25

Tis, but not able to access my bedroom. Invalid password and such Thumbs Up | :thumbsup:

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

Greg Utas15-Jan-20 14:47

15-Jan-20 14:47

I hope your wife didn't change the combination for the door lock.

honey the codewitch15-Jan-20 14:12

15-Jan-20 14:12

It's actually necessary when dealing with naive assemblers or straight machine code as the language doesn't have labels, but it does have jmp instructions.

=)

Real programmers use butterflies

Eddy Vluggen15-Jan-20 14:31

15-Jan-20 14:31

It's not necessary when sharing code, is it?

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]
"If you just follow the bacon Eddy, wherever it leads you, then you won't have to think about politics." -- Some Bell.

honey the codewitch15-Jan-20 14:37

15-Jan-20 14:37

It is because the labels in there refer to jump locations. If i didn't include them you wouldn't know where the split or jmp instructions landed.

Real programmers use butterflies

Greg Utas15-Jan-20 14:01

15-Jan-20 14:01

I actually scanned the regex articles that you posted and have to agree that it's a cool little machine.

I still have fond memories of PDP-10 assembler, in which jrst @. was a one-line infinite loop, roughly the equivalent of

sleep: goto sleep;

honey the codewitch15-Jan-20 14:13

15-Jan-20 14:13

heh.

i like x86's xor ax,ax to set ax to zero. that was just silly, but popular back when everybody bit twiddled.

Real programmers use butterflies

Uh-oh

Mark_Wallace15-Jan-20 20:46

Mark_Wallace

15-Jan-20 20:46

The witch has discovered RegEx.

Brace yourselves, Guys.

I wanna be a eunuchs developer! Pass me a bread knife!

Re: Uh-oh

honey the codewitch16-Jan-20 2:19

Jumping on the hate Microsoft bandwagon

16-Jan-20 2:19

You're kind of late to the party, as I've been writing regex based lexer generators for years. Laugh | :laugh:

Real programmers use butterflies

ZurdoDev15-Jan-20 5:40

15-Jan-20 5:40

They removed the debugger in SSMS 18. What!!!???? OMG | :OMG:

SQL Server Management Studio (SSMS) 18.0 released for general availability - SQL Server Blog[^]

Blasted them!

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Fight for left-handed rights and hand equality.

Rick York15-Jan-20 5:43

Rick York

15-Jan-20 5:43

In their all-knowingness, they determined that no one uses it so it is unnecessary.

On the other hand, was it just moved somewhere, possibly as a stand-alone program?

"They have a consciousness, they have a life, they have a soul! Damn you! Let the rabbits wear glasses! Save our brothers! Can I get an amen?"

ZurdoDev15-Jan-20 5:53

15-Jan-20 5:53

Rick York wrote:
was it just moved somewhere,

Sort of. You can debug t-sql in Visual Studio; however, it does not support conditional breakpoints. D'Oh! | :doh:

Social Media - A platform that makes it easier for the crazies to find each other.

Everyone is born right handed. Only the strongest overcome it.
Fight for left-handed rights and hand equality.

OriginalGriff15-Jan-20 6:04

OriginalGriff

15-Jan-20 6:04

Deebugger? We don' need no steenkin' debugger!

You are getting too soft and pampered, that's the problem. Wink | ;)

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
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ZurdoDev15-Jan-20 7:06

15-Jan-20 7:06

OriginalGriff wrote:
You are getting too soft

Hey, no fat jokes. How rude!

Social Media - A platform that makes it easier for the crazies to find each other.

Everyone is born right handed. Only the strongest overcome it.
Fight for left-handed rights and hand equality.

OriginalGriff15-Jan-20 8:00

OriginalGriff

15-Jan-20 8:00

Well ... I didn't want to mention your avatar, which is getting a bit ... um ... possibly a few bytes too many?

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!

ZurdoDev15-Jan-20 8:20

15-Jan-20 8:20

More 0s than 1s? Laugh | :laugh:

Social Media - A platform that makes it easier for the crazies to find each other.

Everyone is born right handed. Only the strongest overcome it.
Fight for left-handed rights and hand equality.

OriginalGriff15-Jan-20 8:22

OriginalGriff

15-Jan-20 8:22

"I have no idea what I did, but I'm taking full credit for it." - ThisOldTony
AntiTwitter: @DalekDave is now a follower!