Re: [DotGNU]Can treecc help me?

[Rhys Weatherley]

Treecc works best where there are common operations across the entire set of 
nodes.  Also, each case needs to be relatively independent.  That is, the 
operation for a particular node type should be written in terms of just the 
fields in the node, and recursive calls on the children.

Binge may be a good candidate for this - I'd have to study it more closely.  
The generators could probably be turned into node operations fairly easily.

The nodes themselves in Binge.Bits are currently a mixture of data and utility 
routines.  The utility routines would have to be ejected to somewhere else, 
as either node operations, or static methods in some separate utility class.

> Currently, I am using a
> visitor pattern with a little mix of the inheritance pattern.  I've
> seriously thought about moving to an inheritance pattern completely, but
> now I'm in doubt.  Let me describe Binge a little more:

Treecc allows you to easily switch between the inheritance and visitor styles.  
Or have some operations be inheritance, and others be visitors.

> I don't entirely understand treecc.  It seems that you write input files
> for treecc that use an internal treecc language and then treecc will
> generate scaffolding for your compiler in whatever output language you
> choose. Surely, this scaffolding is just stub code and you'd have to
> actually modify the scaffolding to produce a compiler ... but then you are
> likely to regenerate the scaffolding as you flesh out the compiler so then
> you'd have to reinsert the implementation code ... What am I missing?

It doesn't generate scaffolding that you then modify.  It is similar to bison 
in that you insert the implementation code directly into the input files, and 
the tool generates the final scaffolding+implementation.  Consider the 
following from CSConverter.cs:

        public override void Convert (Field field)
        {
            field.TargetName = ReservedName (field.NativeName);
        }

This would turn into something like this:

     %node BingeObject %abstract %typedef
     %node Field BingeObject = { ... }

     %operation %virtual void CSConvert(BingeObject this)

     CSConvert(Field)
     {
            this.TargetName = ReservedName (this.NativeName);
     }

As you can see, the original code is in the treecc input, and will get 
inserted at the correct place when treecc is run.  You then compile the 
output as-is.  There is no need to modify the output further.

As Gopal mentioned, you may want to have a look at the JScript code, as it 
shows using treecc in C# on a substantial system.

Cheers,

Rhys.