Best lex/yacc for C++?

[Moonlit]

Hi,

I am searching for the best lex and yacc combination (or something similar)
that can be used in combination with C++ and that can contain C++ code. I
have the regular flex/bison port working but then I, of course, can't use
C++ constructs in the actions.

I have tried spirit although I could make a simple command line parser
(after too many hours), creating a parser tree with it was not possible in
an easy way (the compiler choked while compiling the include files), so back
to a lex/yacc clone I guess.

Does anyone have any opinion (especially if you have or are using some
implemtation yourself).

Any help appreciated.

Regards, Ron AF Greve.

[Kris Wempa]

"Moonlit" <al******@jupit er.universe> wrote in message
news:3f******** *************** @news.xs4all.nl ...

Hi,

I am searching for the best lex and yacc combination (or something similar) that can be used in combination with C++ and that can contain C++ code. I
have the regular flex/bison port working but then I, of course, can't use
C++ constructs in the actions.

You can write "wrapper" functions that link to and call the actual C++ code.
What C++ code are you looking to use in the actions ?

[tom_usenet]

On Wed, 8 Oct 2003 17:30:56 +0200, "Moonlit"
<al******@jupit er.universe> wrote:

Hi,

I am searching for the best lex and yacc combination (or something similar)
that can be used in combination with C++ and that can contain C++ code. I
have the regular flex/bison port working but then I, of course, can't use
C++ constructs in the actions.

I have tried spirit although I could make a simple command line parser
(after too many hours), creating a parser tree with it was not possible in
an easy way (the compiler choked while compiling the include files), so back
to a lex/yacc clone I guess.

There is a spirit mailing list I believe:

https://lists.sourceforge.net/lists/...spirit-general

Compatibility information is here:

http://www.boost.org/libs/spirit/doc/portability.html

Tom

[Moonlit]

Hi,

Thanks for your reply.

Ah, they should have linked that on their front page I think. Now I see my
vc6 is apparently
not supported (well not the parse trees, but without them ....).

I tried actually their news server but for some reason my news post won't
arrive there though I can read the other posts.

Has someone got experience with some kind of language parser (doesn't have
to be big but at least with more than say 20 rules) with vc7.1 and spirit.

I must admit the way you can write your parser just in C++ code appeals to
me a lot, that's why I spend already so much time on it and I would be
willing to buy the 7.1 compiler just for that, if I would be at least
recently confident that I could use it then (with parse trees of reasonable
size).

Thanks for your reply again.
Regards, Ron AF Greve.



"tom_usenet " <to********@hot mail.com> wrote in message
news:44******** *************** *********@4ax.c om...

On Wed, 8 Oct 2003 17:30:56 +0200, "Moonlit"
<al******@jupit er.universe> wrote:

Hi,

I am searching for the best lex and yacc combination (or something similar)that can be used in combination with C++ and that can contain C++ code. I
have the regular flex/bison port working but then I, of course, can't use
C++ constructs in the actions.

I have tried spirit although I could make a simple command line parser
(after too many hours), creating a parser tree with it was not possible inan easy way (the compiler choked while compiling the include files), so backto a lex/yacc clone I guess.

There is a spirit mailing list I believe:

https://lists.sourceforge.net/lists/...spirit-general

Compatibility information is here:

http://www.boost.org/libs/spirit/doc/portability.html

Tom

[Moonlit]

Hi,

Well amongst other things I would like to fill STL map templates with thing
like var[ "name" ] = etc, also I would call some classes to log info like
"Output << Debuginfo << End;" (the "End" is not a typo). But of course other
things too. In the past I just used a flex/bison scanner and then afterwards
I parsed the tree and created a tree of classes of it. Yes, that works and
it is easy to write but it feals like doing everything twice.

Actually I must admit I have never tried to call C++ from C I know of course
your can wrap stuff like in extern "C" { FILE* yyin; }. Would extern "C++"
{ CWhatEver *ClassFactory() ; } let you do that the other way around? It
would be a solution although of course you get a lot of type casting and
loose the type checking.

Well its worth trying if there isn't a better solution.

Thanks for your reply.

Regards, Ron AF Greve.

"Kris Wempa" <calmincents(NO _SPAM)@yahoo.co m> wrote in message
news:bm******** **@kcweb01.netn ews.att.com...

"Moonlit" <al******@jupit er.universe> wrote in message
news:3f******** *************** @news.xs4all.nl ...

Hi,

I am searching for the best lex and yacc combination (or something similar)

that can be used in combination with C++ and that can contain C++ code. I have the regular flex/bison port working but then I, of course, can't use C++ constructs in the actions.

You can write "wrapper" functions that link to and call the actual C++

code. What C++ code are you looking to use in the actions ?

[Rob Williscroft]

Moonlit wrote in news:3f******** *************** @news.xs4all.nl :

Ah, they should have linked that on their front page I think. Now I
see my vc6 is apparently
not supported (well not the parse trees, but without them ....).

I tried actually their news server but for some reason my news post
won't arrive there though I can read the other posts.
I belive you have too register for there mailing list's before you
can post.

http://www.boost.org/more/mailing_lists.htm

Has someone got experience with some kind of language parser (doesn't
have to be big but at least with more than say 20 rules) with vc7.1
and spirit.

I must admit the way you can write your parser just in C++ code
appeals to me a lot, that's why I spend already so much time on it and
I would be willing to buy the 7.1 compiler just for that, if I would
be at least recently confident that I could use it then (with parse
trees of reasonable size).

Last time I checked the .NET SDK it came with a version (comandline only)
of the 7.1 compiler.

Also see/ask in: news://comp.compilers from what I see the topic is
mostly parsing.
Rob.
--
http://www.victim-prime.dsl.pipex.com/

[Kris Wempa]

"Moonlit" <al******@jupit er.universe> wrote in message
news:3f******** *************** @news.xs4all.nl ...

Hi,

Well amongst other things I would like to fill STL map templates with thing like var[ "name" ] = etc, also I would call some classes to log info like
"Output << Debuginfo << End;" (the "End" is not a typo). But of course other things too. In the past I just used a flex/bison scanner and then afterwards I parsed the tree and created a tree of classes of it. Yes, that works and
it is easy to write but it feals like doing everything twice.

The only way you can use maps this way is to either:

1) create a map instance in a C++ compiler, write C functions to call the
map methods, give these C functions C linkage with: extern "C" {} and call
them from the flex/bison generated C program.

2) write the C only flex/bison code and generate the .c files, manually
edit the .c files to insert your C++ code, compile the resulting code with a
C++ compiler

Step 2 can be messy if your grammar is very large. I haven't looked at
flex/bison output in a long time, so I don't remember how ugly it can get.
Step 1 is easier, but you will also lose the ease of using the maps
directly. You'd essentially be calling a wrapper insert() function instead
of simply assigning the field/value like you have shown above. In other
words:

var[(string) "field"] = ((string) "value");

would become something like

mapinsert("fiel d","value");

I hope these give you some ideas.

[Kris Wempa]

"Kris Wempa" <calmincents(NO _SPAM)@yahoo.co m> wrote in message
news:bm******** **@kcweb01.netn ews.att.com...

1) create a map instance in a C++ compiler, write C functions to call the

Sorry, that should be "in a C++ file" .... not compiler

[Xenos]

"Moonlit" <al******@jupit er.universe> wrote in message
news:3f******** *************** @news.xs4all.nl ...

Hi,

I am searching for the best lex and yacc combination (or something similar) that can be used in combination with C++ and that can contain C++ code. I
have the regular flex/bison port working but then I, of course, can't use
C++ constructs in the actions.

I absolutely love ANLTr. It will generate Java, C++, and C#. I use it for
C++. It has a steep learning curve, but is very powerful. It will generate
LL(k) grammars, and has a lot of neat features like semantic and syntactic
predicates. It generates surprising tight code--looks like a hand-generated
parser. The parse and lexer creation process is well integrated.
http://www.antlr.org
DrX.

[Moonlit]

Hi,

I didn't actually know you could call c from c++ that way, so thanks for the
ideas. However I usually build a tree from the input. In C I creates structs
(with a number assigned so I know what it represents) in most actions an
return pointers to it, what I end up then is a tree that represents the
input. Though it is not impossible to do the same using your first method, I
think it would be not easy to maintain but indeed you would only have to
build a tree once unlike twice as I do it now (first C then convert it to
C++).

Editing the generated code I would rather not, at some point you always
change the grammar and have to redo the changes.

Thanks for the reply.

Regards, Ron AF Greve.
"Kris Wempa" <calmincents(NO _SPAM)@yahoo.co m> wrote in message
news:bm******** **@kcweb01.netn ews.att.com...

"Moonlit" <al******@jupit er.universe> wrote in message
news:3f******** *************** @news.xs4all.nl ...

Hi,

Well amongst other things I would like to fill STL map templates with thing

like var[ "name" ] = etc, also I would call some classes to log info like "Output << Debuginfo << End;" (the "End" is not a typo). But of course

other

things too. In the past I just used a flex/bison scanner and then

afterwards

I parsed the tree and created a tree of classes of it. Yes, that works and it is easy to write but it feals like doing everything twice.

The only way you can use maps this way is to either:

1) create a map instance in a C++ compiler, write C functions to call the
map methods, give these C functions C linkage with: extern "C" {} and call
them from the flex/bison generated C program.

2) write the C only flex/bison code and generate the .c files, manually
edit the .c files to insert your C++ code, compile the resulting code with

a C++ compiler

Step 2 can be messy if your grammar is very large. I haven't looked at
flex/bison output in a long time, so I don't remember how ugly it can get.
Step 1 is easier, but you will also lose the ease of using the maps
directly. You'd essentially be calling a wrapper insert() function instead of simply assigning the field/value like you have shown above. In other
words:

var[(string) "field"] = ((string) "value");

would become something like

mapinsert("fiel d","value");

I hope these give you some ideas.