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30-Jan-20 23:12

Well, I suppose that's progress. I brought my "Rolex" lexer project back from the brink of disaster a few times yesterday and I've finally got it rendering lexers from my preferred input format.

So this:

integerLiteral= '(0x[0-9A-Fa-f]{1,16}|([0-9]+))([Uu][Ll]?|[Ll][Uu]?)?'
floatLiteral= '(([0-9]+)(\.[0-9]+)?([Ee][\+\-]?[0-9]+)?[DdMmFf]?)|((\.[0-9]+)([Ee][\+\-]?[0-9]+)?[DdMmFf]?)'
whitespace<hidden>='[ \t\r\n\v\f]+'
lineComment<hidden>='\/\/[^\n]*'
blockComment<hidden,blockEnd="*/">="/*"
identifier='[_[:IsLetter:]][_[:IsLetterOrDigit:]]*

instead of this nonsense:

%%
[_[:IsLetter:]][_[:IsLetterOrDigit:]]* { return 0; }
\"([^\"]|[\\.])*\" { return 1; }
"+" {return 2;}
"-" {return 3;}
[0-9]+ {return 4;}
[ \t\r\n\v\f]+ { }
.        { return -1; }

And now the output is in a nice, single file, with the primary output implementing IEnumerable<Token>/IEnumerator<Token>

I still have to update the command line argument parsing and a bit of the grammar spec but at least I'll have a deliverable for Codeproject very early this next month

Accomplishing this was so much harder than it looks. I'm using some really grotty code someone else wrote and hasn't maintained for 6 years and I had to retool the front end and back end of it both.

I still barely understand it, but apparently well enough to get it to tease out a lexer that looks how I want it.

The hard part was adjusting the input file format. The original parser is heavily embedded with the app's logic. I had to reverse engineer it, and it's not a hand written parser. It's not even top down so it's impossible to follow in a debugger. It's a table driven LALR(1) parser with syntax directed actions. Fun. =(

I finally went back to the original .y file to get at the parser logic. Of course to change it I had to find an old copy of gppg.exe on the web somewhere (behind a "dangerous" link so I had to wget it - my browser refused to download) - that's so I could get GPLEX to rebuild its parser code.

Anyway, I can see daylight now. I just have to change a few more things with the input spec and then change up the command line argument processing some more.

I'm probably the only person that will ever use this. Laugh | :laugh:

Real programmers use butterflies

MehreenTahir30-Jan-20 23:52

MehreenTahir

30-Jan-20 23:52

Wrong type Poke tongue | ;-P

Consider posting it as a tip or something instead of a lounge post? Laugh | :laugh:

honey the codewitch30-Jan-20 23:53

30-Jan-20 23:53

sorry. i guess the lounge is my rubber duck this morning. i'll back away.

Real programmers use butterflies

MehreenTahir31-Jan-20 4:15

MehreenTahir

31-Jan-20 4:15

honey the codewitch wrote:
sorry. i guess the lounge is my rubber duck this morning. i'll back away.

Oh Please no. I really admire your work and your persistence. In fact I envy you sometime Smile | :)

honey the codewitch31-Jan-20 5:24

31-Jan-20 5:24

Thanks. I just have a lot of time on my hands. Laugh | :laugh:

Anyway, I got it working. Making the devstudio add in now and then i'll have an article

Real programmers use butterflies

Daniel Pfeffer30-Jan-20 23:56

Daniel Pfeffer

30-Jan-20 23:56

For extra credit, rewrite the code in CNoEvil - a library to completely destroy the C language Big Grin | :-D

Seriously, well done. It's unlikely that I'd ever use your program (my interests are more in the direction of scientific computing), but I can appreciate the magnitude of the accomplishment.

Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.

jsc4231-Jan-20 4:21

jsc42

31-Jan-20 4:21

I see that you now allow leading zeros (IIRC, you used to have [1-9]([0-9])+) but you still don't allow leading + or -.

honey the codewitch31-Jan-20 5:20

Happy Brexit Day everybody

31-Jan-20 5:20

because it comes from a different spec. the first one is an excerpt from C#'s spec

Real programmers use butterflies

The pompey30-Jan-20 23:00

The pompey

30-Jan-20 23:00

It’s been drawn out and tedious at times, but today, 3 years later, we will finally deliver on the 17 million f*** offs to the EU.

musefan30-Jan-20 23:11

musefan

30-Jan-20 23:11

Will tomorrow still be called Saturday, or nah?

I just want to be sure that when I tell the boss "F*** off it's Saturday!" that I don't make myself look stupid.

Daniel Pfeffer30-Jan-20 23:38

Daniel Pfeffer

30-Jan-20 23:38

Parsing ambiguity: is "F*** off" an instruction, or a name? Big Grin | :-D

Freedom is the freedom to say that two plus two make four. If that is granted, all else follows.
-- 6079 Smith W.

musefan30-Jan-20 23:59

musefan

30-Jan-20 23:59

Did you see a comma, mother******? Wink | ;)

Nelek31-Jan-20 4:41

Nelek

31-Jan-20 4:41

Daniel Pfeffer wrote:
Parsing ambiguity: is "F*** off" an instruction, or a name?

ask the witch above Wink | ;)

M.D.V.

If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
Rating helpful answers is nice, but saying thanks can be even nicer.

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Pete O'Hanlon31-Jan-20 0:52

Pete O'Hanlon

31-Jan-20 0:52

Getting a bit political in the Lounge mate. Best avoided.

glennPattonWork331-Jan-20 1:16

glennPattonWork3

31-Jan-20 1:16

Mind you he has been Pompey3 I think for a long time, didn't try to get barred every day at one time?

The pompey31-Jan-20 7:20

The pompey

31-Jan-20 7:20

No. Just forget accounts

Nagy Vilmos31-Jan-20 3:14

Nagy Vilmos

31-Jan-20 3:14

Pete O'Hanlon wrote:
Getting a bit political

My name's Ben Elton, thank-you, GOOD NIGHT!

veni bibi saltavi

glennPattonWork331-Jan-20 6:51

glennPattonWork3

31-Jan-20 6:51

So Mr Vilimos, still with us in sprit! Big Grin | :-D

ZurdoDev31-Jan-20 7:20

ZurdoDev

31-Jan-20 7:20

glennPattonWork wrote:
sprit

I thought, based on his reputation, that he's always in spirit. Big Grin | :-D

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