D1 -> D2

[Walter Bright]

Andrew Wiley wrote:
> I'm a fan of parsing false version blocks, but it seems like there 
> should be some sort of exception for version blocks for a different 
> version of the language. Could they just be skipped with a warning that 
> an unknown version of the language is in use? It's somewhat hackish, but 
> to me, that seems better than parsing it and giving an error because of 
> syntax changes. 


How can it skip it without knowing the grammar?