Re: scratch/accurate-warning-pos: Solid progress: the branch now bootstraps.

[Paul Eggert]

On 11/28/18 4:04 AM, Alan Mackenzie wrote:

> Assuming the macro is compiled, just where are these cons positions
> going to be stored?

The same place we store the rest of compiled output. That is, when we 
byte-compile macros, we store the uncompiled macros (with source-pos 
info) into the .elc file. Then, any code that wants accurate line number 
or similar debugging information for the macro can use the uncompiled 
version. It's pretty common to bloat object files to support debugging 
in this way.

This approach wouldn't work for .elc files generated by older versions 
of Emacs, but that's OK; the old macros should still work, it's just 
that the byte-compiler's diagnostics will be just as bad as before.

(Sorry, I don't know how edebug works so I don't know how this would 
affect edebug.)

> You're wrong, here.  Symbols-with-pos works on the output from macros.
> Conses-with-pos will only do so for some "nice" macros, ones which
> preserve their input conses.
I'm afraid we'll have to disagree here, as I can see examples where 
symbols-with-pos fails and conses-with-pos works (as well as vice 
versa). The only good way I see to resolve the disagreement would be to 
build it both ways and see which typically works better in the real 
world. A daunting prospect, admittedly.