Hi!
I still don't know what is the official way to edit component being compiled. I asked at comp.lang.lisp but had no reply.
But I have developed my own solution. For this I had to redefine several asdf functions. I bind special variables so that current component is known at the time of compilation. Also I define asdf::e and asdf::ep symbol macros that access special variables.
When compilation fails, I have an EDIT-COMPONENT restart, which is not needed - it is just a help string. Then user should eval asdf::e in the debugger to edit component source. User should eval asdf::ep in the debugger to edit component's system source.
Code is here, it shoud work in asdf-3.1.4 under lispworks 6 or under SBCL+SLIME.
https://bitbucket.org/budden/budden-tools/src/866bcf15ad5c793868a0a31e602474...
I'd like to receive any feedback.