On 2024-06-26 18:04, Andy Wingo wrote: > On Wed 26 Jun 2024 11:36, Maxime Devos <maximede...@telenet.be> writes: > >> IIRC, the question wasn’t about debugging in general, it was about >> source locations in particular. Surely program-sources (or, in this >> case, procedure-source maybe?) (why are the procedures in this family >> even named program-whatever, this prevents doing the same for >> interpreted code later) could be adjusted to also work for ‘eval’. For >> example, ‘eval’ could set the ‘source’ (*) procedure property when a >> closure is made. > > I think it's really valuable to imagine how things should be but if you > are going to argue they should be different, you should first try to > understand how they are. > > `program-sources` is a mapping from bytecode offsets to source > locations. For compiled procedures we can make this mapping because > each bytecode position has a single source. For interpreted procedures, > what you end up getting is the bytecode-to-source mapping *for eval*, > not for the code being interpreted. > > Is it a great thing that there is a debugging (I use the term on purpose > to mean all kinds of run-time reflection etc) difference between eval > and compile? No, of course not. I would rather there not be a > difference and not have to document something that is at best > extraneous. There are differing pressures on eval: for bootstrap times > (and macro expansion time) you want it to have the least amount of > overhead possible, whereas for debugging you want to attach meta-data > that isn't strictly needed at run-time. Attaching that meta-data has > memory and time overheads.
Does it mean, we could want another eval implementation, which is a bit havier, but will preserve additional meta-data? not-that-primitive-and-a-bit-fancier-eval :) > > If we are looking to get the source location *just of the interpreted > closure* -- that is possible; see eval.scm:581, there you would attach > some other properties. You would have to define a different debugging > interface that looks for source location information in a way different > from program-sources. For me it's not worth it but I encourage you to > experiment with (ice-9 eval); it's just another Scheme program. (You > would need to take a different approach to memoization, in order to pass > through source location information.) > > Andy -- Best regards, Andrew Tropin
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