Re: Dynamic loading progress

[Aurélien Aptel]

I've made a github repo of my work so far:
https://github.com/aaptel/emacs-dynamic-module

On Mon, Jul 7, 2014 at 3:19 AM, Stefan Monnier <address@hidden> wrote:
> The `doc' field could simply be changed to be of type Lisp_Object and
> then follow the usual representation used for lambda expressions

I've followed your advice.

a) I've updated the type of the doc field. I'm initializing it to 0 in
the DEFUN macro and I set it to Qnil in defsubr(). I'm not
initializing the field directly to Qnil because the docs reads:

  You must not use C initializers for static or global variables unless
  the variables are never written once Emacs is dumped. These variables
  with initializers are allocated in an area of memory that becomes
  read-only (on certain operating systems) as a result of dumping
  Emacs. See Pure Storage.

Instead of duplicating the Fsnarf_documentation code for handling
modules I've added a boolean 'module' parameter. If the function
snarfs a module documentation, don't overwrite the global DOC file
path and store a (FILE . OFFSET) cons instead of a simple offset. This
part works correctly.

b) Now, when fetching a function docstring with Fdocumentation, I
check the types and let the existing get_doc_string() handle the field
itself.

It should work but I've ran into a strange problem: the doc field is
set correctly in step a) but the field becomes either an invalid lisp
object or garbage at step b).

I've added debug print statement (using safe_debug_print):

# this is after calling load-module
---
fmod
("/home/knarf/prog/c/emacs/dyn/modules/fmod.doc" . -16)
---

---
fmod-test1
("/home/knarf/prog/c/emacs/dyn/modules/fmod.doc" . -98)
---

---
fmod-test2
("/home/knarf/prog/c/emacs/dyn/modules/fmod.doc" . -125)
---

---
fmod-test3
("/home/knarf/prog/c/emacs/dyn/modules/fmod.doc" . -152)
---

# now calling (documentation 'fmod...)

--Fdocumentation
fmod
#<INVALID_LISP_OBJECT 0x0322a986>
---

--Fdocumentation
fmod-test1
#<INVALID_LISP_OBJECT 0x0322a996>
---

--Fdocumentation
fmod-test2
((keymap #^[nil nil keymap
#^^[3 0 set-mark-comma...
# [garbage]
---

It suspect it has to do with garbage collecting since I have not done
anything special to protect the doc field. I'm not sure how to
proceed.