Hans-Peter Diettrich wrote:
You obviously missed that a compiler does not only consist of scanner and parser, but that optimizers and code generators also have to be implemented. For multiple target platforms and CPU's...
The new dialect simply makes the syntax less annoying and verbose - it wont alter functionality as such so altering those shouldn't be on the agenda (I hope!).
The new dialect simply requires a multi pass parser. It shouldn't be too hard to adapt the existing one for this purpose. Of course the compiler will only use this if the source file tells it to use Rad Pascal dialect so it wont affect or harm compiler performance of other dialects.
I can also totally eliminate circular refs in the multi pass phase (it will require three passes if there are circular refs, otherwise one or two passes will be sufficient). The advantage for the developer here is that only one uses clause ever needs to be used.
Looking at the tokens.pas file in the compiler, every token in the parser is specified against which dialect implements it (via the mode switch) so it shouldn't be too difficult to remove any redundant syntax where its not needed. (I emphasize removing not adding syntax here!)
The safe approach is to write an preprocessor, that can translate your dialect into any implemented language, so that the compiler code must not be touched. Then you'll find out that your dialect needs code completion and other features, that have to be implemented as well, apart from the compiler. These are fine exercises before you start bothering with the compiler code.
I had thought of that but thats problematic for debugging. IE the compiler returns line numbers for errors and they will not match if I use an external preprocessor.
For replacing Begin..End blocks with indents in my new dialect I planned to use the compiler's internal preprocessor in the compiler to put back the begin/end blocks without affecting the line numbers. I can do likewise for syntactic sugar.
If you or anybody else has advise on how best to implement it then please let me know - I apreciate anything that will help me here.
Thanks jamie. _______________________________________________ fpc-devel maillist - fpc-devel@lists.freepascal.org http://lists.freepascal.org/mailman/listinfo/fpc-devel
