Thanks, Faré. Quick follow up: is there any construct that has semantics like "If this feature is not in features, fail"?
On February 22, 2014 4:22:17 PM CST, "Faré" fare@tunes.org wrote:
On Sat, Feb 22, 2014 at 2:56 PM, Robert P. Goldman rpgoldman@sift.info wrote:
I see that the grammar of dependencies in the manual specifies that :version appears as a keyword symbol, but feature appears as *not* a keyword symbol.
Is this a documentation bug? I think so, but you know the actual execution semantics better.
If it is a doc bug, I'll fix it right away.
Beware that there are two "feature" features
1- In a depends-on specification, as defined in find-component.lisp, you can write (:feature <feature-expression> <dependency-spec>), where the dependency link is valid if <feature-expression> is true as per featurep. This feature was hidden in the ASDF 1 code, but I'm not convinced this feature worked before ASDF 3, when I fixed it for good. Therefore, I'm pretty sure noone uses this feature.
2- In a component-depends-on method or in-order-to specification, (feature foo) instead of (operation components...) then a missing dependency error is raised. This was used in conjunction with the ill-designed :if-component-dep-fails feature to provide conditional dependency. This later feature was removed (minus a thin partial compatibility layer for old SBCLs), because it was not compatible with the fixed ASDF3 dependency model.
I suggest both features should probably be deprecated and removed, and the :if-feature feature introduced in ASDF3, that actually works. If any system anywhere uses these features, they should be fixed ASAP.
We should probably run a cl-test-grid test with these features disabled. See patch attached.
NB: I obviously cannot commit this patch unless the maintainer wants me to. Robert, this baby is yours. The diff above also doesn't remove the misfeatures from the tests and documentation.
—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org The program isn't debugged until the last user is dead.