[antlr-interest] python grammar(s)

[alexander krohn]

(sorry, i've sent this directly)

hi, johannes.

Johannes Luber schrieb:
> alexander krohn schrieb:
>> [...]
>> there are some more things python does not accept, while the antlr 
>> grammars do. how comes?
>>
>> are these just meant as examples?
>
> My theory is that the ANTLR python grammars are supersets over the 
> specification on python.org. Such grammar definitions tend to include 
> semantic limitations, which could be included in BNF form, but make it 
> more difficult to create good error diagnostics from. The solution is 
> then to do a second pass which filters the wrong semantics out.
>
> Johannes
>
can you explain what you mean by "semantic limitations"?

what would the second pass look like? what grammar should it use? a tree 
grammar maybe?

i want to do a mostly complete transformation using a heterogenous ast 
build by using rule arguments and return values. this puts more stuff to 
the rules than using rewrite rules but the result is really nice.

regards

alexander