> Originally I *did* want to operate on AST, because I couldn't get macro
> system to parse more than the first statement when I was writing my rules
> like this:
> ( $head:stmt ; $($rest:*stmt*);+ ) => ( $head ; stmt_list!(
> $($rest);+ ) );
> Apparently interpolated statements cannot be re-parsed again?
>
Correct.
>
> Is tt specifier documented somewhere? I am guessing it stands for "token
> tree", but what is a token tree? How is it different from AST?
>
A token tree is "almost unparsed": it consists of a sequence of tokens
surrounded by `()`, `[]`, or `{}`, or a single token. It's the AST node
that the macro parser knows how to parse into actually useful AST nodes. It
isn't documented, sadly.
>
>
>> macro_rules! stmt_list(
>> ( while $cond:expr { $($body:tt)+ } ) =>
>> ( while $cond { stmt_list!( $($body)+ ) } );
>> ( $head:stmt ; $($rest:tt)+ ) =>
>> ( $head ; stmt_list!( $($rest)+ ) );
>> ( $head:stmt ) =>
>> ( $head );
>> )
>>
> That doesn't seem to work :-(
>
Could you try wrapping `{}` inside the parens on the 2nd RHS, and adding a
semicolon after all three invocations of `stmt_list!`? For future debugging
back-and-forth, please contact me in #rust (I'm `pauls`), since that'll be
easier than email?
Paul
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