On Sunday, 6 September 2015 at 21:16:18 UTC, Prudence wrote:
Yeah, but wouldn't it be so much nicer? (and probably
debuggable inline)
interpret({
var a = 5;
a += 2;
a;
}
Not really because that already more-or-less works today (add a q
before that { and it will compile).
The interpreter throws exceptions when it gets a bad program;
syntax errors, runtime errors, etc. Those exceptions are
propagated to the compiler user in the form of error messages.
Delete the last semicolon and rerun it. The compiler now spews:
/home/me/arsd/script.d(2164): Error: uncaught CTFE exception
arsd.script.ScriptCompileException("4: Parse error, unexpected
end of input when reading expression, expecting ;")
d.d(4): called from here: interpret("\x0a\x09\x09var a =
5;\x0a\x09\x09a += 2;\x0a\x09\x09a\x0a\x09", var(cast(Type)0,
Payload(null, , , , , , )).this(null), null)
d.d(9): while evaluating pragma(msg, a)
d.d line 4 is the interpret function call. The error message from
the interpreter is listed above that and lists line 4 of its
input.
So it isn't exactly nice to read.... but probably could be. Keep
in mind that I didn't write this thing for compile time, it is a
runtime script interpreter that just happens to also work at
compile time. If I wrote a thing that caught that exception and
nicely formatted it at compile time, it could be made prettier.
But still, that message *does* contain the information you need
because exceptions from the external parser are returned to the D
compiler.
THAT SAID, I do know what you're asking and I've kinda wanted it
before. It would be nice to have a .sourceof for an alias
function (and I think that's been implemented in a pull request
before, it isn't impossible to do). I just don't feel it would be
all that important, since what we have now really goes a very
long way.
