[antlr-interest] handling /// comments

[ajk .]

Yes unfortunately it is v2, our parser is quite large and translating it to
v3 with all the ad hoc functionality would be a major undertaking.

BR/Anders.

On Sun, Sep 21, 2008 at 6:56 PM, Johannes Luber <jaluber at gmx.de> wrote:

> ajk . schrieb:
> >
> >
> > On Fri, Sep 19, 2008 at 10:47 PM, Johannes Luber <jaluber at gmx.de
> > <mailto:jaluber at gmx.de>> wrote:
> >
> >     ajk . schrieb:
> >     > Hi
> >     >
> >     > I was wondering if somebody has an idea how to solve the following
> >     > problem. Lets see if I can describe the issue in a proper way.
> >     >
> >     > We have a translator that translates a scripting language to C#.
> >     >
> >     > We now need to support ///<summary>.. in C#
> >     >
> >     > By adding the /// in the scripting language we were hoping just to
> >     move
> >     > this over to C#:
> >     >
> >     > example
> >     >
> >     > /// <summary>
> >     > /// some function
> >     > /// </summary>
> >     > myfunction returns int
> >     > begin
> >     >    bla();
> >     > end
> >     >
> >     > ->
> >     >
> >     > C#
> >     > /// <summary>
> >     > /// some function
> >     > /// </summary>
> >     > int myfunction()
> >     > {
> >     >   bla();
> >     > }
> >     >
> >     > So far so good, I would associate the comments to the following
> >     function
> >     > which is a node in the AST, simple to do a parser rule for this.
> >     >
> >     > But in C# (as well as the scripting language) you can write
> comments
> >     > anywhere in the code in whatever form you want e.g.
> >     >
> >     > /// hello
> >     >
> >     > or
> >     >
> >     > ///////////////////////////////////////////
> >     > //// this freestanding comment
> >     > ////////////////////////////////////////////
> >     >
> >     > How do you filter away these things? How do I write a parser rule
> that
> >     > allows comments anywhere in the original code but only move the
> >     relevant
> >     > ones? i.e. the ones associated with certain elements like
> functions,
> >     > variable declarations etc.
> >     >
> >     > TIA
> >     > Anders.
> >
> >     There are two possible ways to solve this issue. The first is to add
> >     COMMENT nodes everywhere they may appear. But this reduces the
> >     readability a lot. The other way is to put off the COMMENT tokens
> >     off-channel and to scan in front of matched function definitions for
> a
> >     COMMENT token yourself.
> >
> >     Johannes
> >
> >
> >
> > The latter method sounds better, our language is very large so the less
> > changes to the grammar the better. In v2 (which I am not familiar with)
> > how to set tokens to come into the hidden channel? In v3 you just write
> > $Channel=HIDDEN right?
>
> Are you using v2? I haven't used it myself, too, so I can't help you
> there. In v3 one uses "{$channel=HIDDEN;}", but theoretically one can
> use other values, which is useful to distinguish between comments and
> other whitespace.
>
> Johannes
> >
> > thanks
> > Anders.
>
>
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