D Parser in D

[Timon Gehr]

On 11/27/2011 12:05 AM, Trass3r wrote:
>>> Is there a D parser written in D? - C strings kill me.
>> It's annoying to write one as long as the buffered input range with
>> infinite lookahead problem is not solved by the std library.
>
> What do you need infinite lookahead for?

There are a few places in the grammar where it is useful, for example:


void foo(A,B,C,...)(A,B,C,...){}

vs

void foo(A,B,C,...){}

Without looking behind the first set of parentheses, it is harder to 
figure out whether or not foo is a function template.

Another example:

void main(){
     a[][][][][]...[][][] b;
}

vs

void main(){
     a[][][][][]...[][][] = b[];
}

Both of them could in theory be parsed without infinite lookahead, but 
that is more complicated than the solution using infinite lookahead.

Also, if eg. you want to build a distinct AST representation for 
template parameters and function parameters, infinite lookahead is the 
only sensible option.