good afternoon;
On 2010-03-18, at 16:23 , Faré wrote:
[ ...]
But I think ASDF ought to make a best effort, so that you can at the very least upgrade ASDF when installed as part of Common-Lisp-Controller and similar management layers (that do use package ASDF).
as a step in that direction, let us enumerate the actions which an upgrade could contemplate and come to terms with the consequences on existing code. in the note below, "not permitted" refers to a situation where the modification must be compatible with a running system and/or binary files, to be loaded as is, without recourse to source files for recompilation.
package renaming : is not permitted package deletion : is not permitted package aliasing : is permitted, as long as the name is new
symbol export : is not permitted, as the new export can conflict with the content of a using package symbol unexport : is not permitted, as it could eliminate a previously visible symbol symbol uninterning : is not permitted, as it would compromises existing references
plain function redefinition as generic : if done with fmakunbound, this is permitted, as only the library definition can exist. generic function redefinition as plain : this is not permitted, as it could purge extension methods.
generic function redefinition : via defgeneric is permitted, that is, so long as the lambda list is compatible, as it should not effect extension methods. via fmakunbound is not permitted, as it could purge extension methods. this means that the present (ensure- package :fmakunbound) semantics must be changed to distinguish plain and generic functions.
method deletion : as long as the method specializers are asdf classes or common-lisp classes, this is permitted, as this no extension function should fit that constraint. this could be automated independent of generic function redefinition as a means to clean a package of incompatible definitions. (ensure-package :fmakunbound) could use this approach.
method addition : same as deletion
method redefinition : same as deletion
variable rebinding : should be permitted. there are no constants.
wrt. methods on the basis of 1.648, there are very few methods which are not already fully specialized and as such amenable to such rules.
perform-with-restarts has a default method as the next method for the :around methods. one could argue that this should be distinct base methods, but i don't see a clear reason to do that - especially as it is intended to be _the_ default method. output-files has an :around method which could be specialized.
are there other modifications?
are there other methods?