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#67455
Record source position, etc., in doc strings, and use this in *Help* and backtraces.
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Hello, Stefan.
On Sun, Mar 10, 2024 at 17:03:28 -0400, Stefan Monnier wrote:
> >> >> - Testing `byte-compile-in-progress` can't be right. Do you to test
> >> >> whether the result of this backquote will be byte-compiled or do you
> >> >> really mean to test whether this backquote happens to be executed
> >> >> during compilation (which could be because the compiler ends up
> >> >> loading code while executing `eval-when-compile` or `require`)?
> >> > Quite simply, during compilation, all symbols (except nil) get read with
> >> > position, so to strip their positions here would be wrong.
> >> This isn't quite right: during compilation, some code is read with
> >> positions (the code that we will compile), but some code is read in the
> >> normal way (the code we load for the purpose of running).
> >> The distinction is important.
> > OK, I wasn't really counting code that we load as "during compilation",
> > but I take the point.
> The point is that `byte-compile-in-progress` will be non-nil during
> those loads, so you can't use this variable to get the information you need.
Yes. How about binding it to nil around `load' and recursive edits, and
possibly one or two other things?
> >> More generally: what goes wrong in the above example if you just treat
> >> that as a list of symbol (stripping them all of their position info).
> >> AFAICT when *that* macro is expanded (i.e. ME2) you'll presumably get
> >> code like
> >> (mapatoms #'(lambda (FOO/p) (DO/p SOME/p (THING/p))))
> >> right? [ where "/p" means that the symbol has a sympos. ]
> >> Isn't that sufficient info to add a docstring with position?
> > It's the lambda which has a position rather than the expanded bits from
> > ME2.
> Hmm... then I misunderstand something. How can the `lambda` have
> a position if you don't include any special treatment of backquote?
In read-positioning-defined-symbols, lambdas get positioned, along with
symbols being defined by defun, defmacro, cl-defmethod, .... This is not
to do with backquote handling.
> AFAICT the `lambda` in the result of ME1 should not include position
> information because at that time we don't know that it will be used to
> build code rather than be some element of a normal list.
read-positioning-defined-symbols cannot know how (lambda ...) is going to
be used. It is up to other code (here, macroexp--expand-all) to strip
the position from the lambda when it would be obtrusive.
> And how come the rest doesn't have position information?
read-positioning-defined-symbols is specifically coded (with a state
machine) to position only the lambdas and the defined symbols.
> Stefan
--
Alan Mackenzie (Nuremberg, Germany).
This bug report was last modified 1 year and 11 days ago.
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