Greetings, and thanks for isolating this example! Your suspicions are hardly naive -- the compiler makes a first pass over the top level forms in sequence, collecting information as it goes, then writes the output in pass 2 using said information. This means that a defun calling one further down in the file will not have available its auto-proclamation info, etc., leaving any conflicts to be resolved at load time.
This will obviously get simple (i.e. self) recursion wrong, so the compiler iterates over the pass1 processing of the single top level form in question in this case. In general, in the case where all functions are in the same file, it would be possible to effectively do the recompile before writing the output in pass2. This will only mitigate, and not eliminate, the necessity of recompiling at load time, which you feel is deprecated, I'm sure with good reason. I had thought that since this would not solve the entire problem, best to do the conflict resolution in one place for all cases, i.e. at load time. I'm most interested in your example for another reason, as it exposes a weakness in the current algorithm in the case of mutual recursion. Chicken-and-egg ordering/bootstrapping problems aside, the signature arrived at here was ((fixnum fixnum fixnum) *), not ((fixnum fixnum fixnum) fixnum), (as is the case for a simple self-recursion version of tak, as I've just confirmed). We need to sketch out a good algorithm here. (Initially, I had naively thought that this could be resolved easily using reverse type propagation, at least in this case, using the call to tak0 using as (known fixnum) argument the result from tak1, but this clearly won't work at all, as the function result type could vary with input, and even return multiple values). Somehow, we have to do the simple-recursion iteration across multiple functions, and again the comprehensive time to do this is at load time. The way the former (i.e. self-recursion) works is to assume the return type is nil, compile the function, get an expanded return type, and recompile until we get the same result twice. Suggestions as always most welcome. If it would be helpful, I can describe how the compiler sees each function below at the various stages of the compile and load process. You can as well by compiling one at a time and checking the contents of (gethash 'tak0 si::*call-hash-table*) and si::*needs-recompile*. Take care, Robert Boyer <[EMAIL PROTECTED]> writes: > Ok, let me try my question again, in somewhat simplified > form, though still too long. > > Why can't you do the COMPILE-FILE below "right" the first > time? There is only one file in sight, foo.cl. There are > only two functions in sight, tak0 and tak1. My naive > feeling is that you are probably "committing" to a signature > for tak0 before you should, and that's why you have to > recompile tak0 later, during the load, which is deprecated! > > Bob > > % cat foo.cl > (defun tak0 (x y z) > (declare (type fixnum x y z)) > (cond ((not (< y x)) z) > (t (tak1 (tak0 (the fixnum (1- x)) y z) > (tak1 (the fixnum (1- y)) z x) > (tak0 (the fixnum (1- z)) x y))))) > (defun tak1 (x y z) > (declare (type fixnum x y z)) > (cond ((not (< y x)) z) > (t (tak0 (tak0 (the fixnum (1- x)) y z) > (tak1 (the fixnum (1- y)) z x) > (tak0 (the fixnum (1- z)) x y))))) > > % xg > GCL (GNU Common Lisp) 2.7.0 ANSI Jun 6 2006 15:29:37 > Source License: LGPL(gcl,gmp,pargcl), GPL(unexec,bfd) > Binary License: GPL due to GPL'ed components: (BFD UNEXEC) > Modifications of this banner must retain notice of a compatible license > Dedicated to the memory of W. Schelter > > Use (help) to get some basic information on how to use GCL. > > Temporary directory for compiler files set to /tmp/ > > >(compile-file "foo.cl") > > ;; Compiling foo.cl. > ;; End of Pass 1. > ;; End of Pass 2. > ;; OPTIMIZE levels: Safety=0 (No runtime error checking), Space=0, Speed=3, > (Debug quality ignored) > ;; Finished compiling foo.o. > #P"/v/filer2/boyer/gabriel/foo.o" > NIL > NIL > > >(bye) > % xg > GCL (GNU Common Lisp) 2.7.0 ANSI Jun 6 2006 15:29:37 > Source License: LGPL(gcl,gmp,pargcl), GPL(unexec,bfd) > Binary License: GPL due to GPL'ed components: (BFD UNEXEC) > Modifications of this banner must retain notice of a compatible license > Dedicated to the memory of W. Schelter > > Use (help) to get some basic information on how to use GCL. > > Temporary directory for compiler files set to /tmp/ > > >(load "foo.o") > > Loading foo.o > Callee TAK1 sigchange NIL to ((FIXNUM FIXNUM FIXNUM) *), recompiling TAK0 > ;; Compiling /tmp/recompile.lsp. > ;; End of Pass 1. > ;; End of Pass 2. > ;; OPTIMIZE levels: Safety=0 (No runtime error checking), Space=0, Speed=3, > (Debug quality ignored) > ;; Finished compiling /tmp/recompile.o. > Loading /tmp/recompile.o > start address -T 0xaf17650 Finished loading /tmp/recompile.o > start address -T 0xaf12290 Finished loading foo.o > 2156 > > > > > > -- Camm Maguire [EMAIL PROTECTED] ========================================================================== "The earth is but one country, and mankind its citizens." -- Baha'u'llah _______________________________________________ Gcl-devel mailing list Gcl-devel@gnu.org http://lists.gnu.org/mailman/listinfo/gcl-devel
