extern(C++, "somestring") syntaxCheck error

[rmanthorpe]

D-Scanner doesn't seem to understand extern(C++) string namespace syntax.
--- foo.d ---

module foo;
extern (C++,"bar")
struct Foo{}

$ dscanner.exe --syntaxCheck foo.d
foo.d(2:13)[error]:

[Hackerpilot]

I think that I found the problem at the root of several of your bug reports: https://dlang.org/spec/grammar.html#LinkageAttribute

Note that the specification says that the part that follows extern(C++, needs to be an identifier list, and not a string literal. Since libdparse is based off of the language specification, it rejects this code. If the compiler accepts it, we need to 1) fix the specification, and 2) change libdparse.

[Hackerpilot]

Found it: https://dlang.org/changelog/2.083.0.html#mangle_cpp

This was an intentional change to the language that never made it into the spec.

[Hackerpilot]

This gets dumber. I dug into the parser code in DMD and found that it's not looking for string literals. It's looking for a list of conditional expressions, or in other words, a list of basically anything.

enum a = 10;
extern (C++, "a", "b", "c") int b();
extern (C++, "something" ~ (a > 1 ? "A" : "B")) int c();

[rmanthorpe]

Fun! I guess the question now is, was that the intended behaviour and should the spec reflect that, or should the spec just accept string literals?

[Hackerpilot]

It's probably the way it is so that you can use enums of type string or CTFE code to generate the namespace.

[rmanthorpe]

Thanks for your input. I've added a PR for the grammar here: dlang/dlang.org#2716