Another Phobos2 test

[spir]

On 02/08/2011 04:11 PM, Adam Ruppe wrote:
>> I know, but I was suggesting something different, to turn the JSON
>> >  creation into some kind of Phobos library that you may call at
>> >  compile-time from normal D code. Then a compile-time JSON reader in
>> >  Phobos will allow to perform certain kinds of static introspection,
>> >  that later will be quite useful to create user-defined @annotations.
> We could do that today with a combination of -X, -J, and a CTFE
> JSON parser (it's possible that std.json would work today. I haven't
> tried it specifically, but ctfe tends to surprise me with its
> capabilities).
>
> Of course, you'd have to run the compiler twice, but there's other
> advantages to that too (like getting dependencies - my build tool
> does this - and the first run is fast anyway.
>
>
> I'm tempted to do it now just to prove we can... but I'm already
> a bit loaded with stuff to do.

What I dream of is something a bit different: a D "decoder" (lexical, 
syntactic, semantic(*) analyser) that constructs an AST as a plain D data 
structure --without any fancy stuff. And writes it out on demand as a D module 
(in static this(), since for a reason I haven't yet caught data description can 
only go there).
I can't even start to imagine all what we could then do /easily/. (we would 
even have type defs in D... would change from obscure RTTI)

=================================
import std.stdio;
a = 1;
void main () {
     writeln(a);
}
=================================
==>
=================================
import AST;	// Node types, mainly
Module module;

static this () {
     module = Module ([
         Import("std.stdio"),
         Assignment("a", Integer(1)),
         FunctionDef(
             /* name */      "main",
             /* params */    [],
             /* block */     [
                 FunctionCall(
                     /* name */   "writeln",
                     /* args */   [Symbol(a)]
                 )
             ]
         )
     ]);
}
=================================

Too bad we're missing named args, would be highly helpful here; but we can 
probably survive that...
(Yes, Bearophile, there's certainly a bug report for this ;-)

I would enjoy writing a prototype when I have some time (not tomorrow), for a 
tiny subset of D (kind of proof of concept).

Denis

(*) As far as possible.
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