Altering ASDF execution plan

[Robert Goldman]

On 5/30/16 May 30 -11:04 AM, Vsevolod Dyomkin wrote:
> Hi,
> 
> I have a few questions about controlling ASDF execution of compile/load
> operations:
> 
> 1. Suppose I have performed successful `load-op` on a certain system.
> After some time and no changes to the source code of the system nor its
> dependencies, I run `load-system` again on the same system. How can I
> ensure that no compile/load action is performed?

This should simply happen. If unnecessary operations occur when you do
this then either (a) you have found a bug in ASDF or (b) you have found
a "bug" in a system definition.

I put "bug" in scare quotes there, since a system definition should
provide a conservative estimate of when recompilation is necessary.
Sometimes it may not be possible for ASDF to tell whether or not a
recompilation is necessary -- it has only limited information to go on
-- and in that case the conservative thing to do is to perform
operations that might not be necessary.

For example, I work with a somewhat pathological system that makes
changes in the state of memory that do not follow good dependency
practices.  That system must always be reloaded in its entirety if
anything in it changes. But most systems do not have that issue (thank
goodness)!

Question: why do you say "no compile/LOAD [emphasis mine] is performed"?
 If you request a load, then you get a load.  I believe you mean "After
some time and no changes ... AND I HAVE NOT RESTARTED MY LISP," correct?


> 
> 2. Suppose I have a system `foo` that depends on `bar`. Now, I
> explicitly call `(load-system :bar)`. How can I ensure that when I call
> `(load-system :foo)` no compile/load action is performed on `bar`?

That should automatically happen: ASDF should check bar, note that no
changes have been made to it, and take the previous load as sufficient.