> That will always parse to an associative array. Then in the semantic pass, if
> U
is a constant expression that turns out to be an integer it is reinterpreted as
a
static array.
Ah, interesting. But that describes the implementation (i.e. how the compiler
copes with the ambiguity) and not the language itself.
> Context-free means that it's unambiguous as to which grammar rule is to be
applied at any point during the parsing process.
The problem is that it _is_ ambiguous what rule to apply. To me, just because
static arrays and associative arrays happen to have similar _looks_ doesn't make
parsing them context-free -- they're defined with completely separate syntaxes,
and they just happen to look identical. The fact that the compiler has to do a
semantic analysis in order to figure this out (which was originally a syntax
problem) really makes me wonder why you mention that D is still context-free.
> Not to mention, the context-free grammar is entirely for parsing tokens into
> an
abstract syntax tree.
Again, just because the AST's _happen_ to _look_ the same for static and
associative arrays, does that mean that this makes D context-free? The meaning
of
the expression is still ambiguous, whether or not it fits well within the tree.
Furthermore, I would say that a struct like this:
struct Temp(T...) { int[T] arr; }
should work perfectly if T.length == 0, since it would then be a dynamic array.
But the parser is forced to treat it as an associative array, and so _both_ of
these break:
Temp!() a;
Temp!(2) b; //Why does this break?
Why should the second one break, in any case?
