Bryan C. Warnock asked:
> Is it POST, LAST or LAST, POST, at runtime?
LAST then POST I suspect. For reasons already given in someone else's
reply. But, just possibly: intermixed in reverse order of definition.
> How does one enforce the no side-effects rule, and how deeply does it
> traverse?
By prohibiting mutation of variables not lexical to the block,
forbidding I/O, allowing calls only to already-defined subs, and
applying the same restrictions recursively to those subs.
> Do I remember right that 'return' creates a control exception?
Yes.
> Do KEEP and UNDO take the place of CATCH within a block? (ie, you may
> either CATCH, or you may KEEP and UNDO, but not both?
Correct. KEEP+UNDO = CATCH and you can only have one CATCH per block.
> If one cannot (or does not) inherit a PRE, POST, or LAST block,
LAST blocks aren't ever inherited.
> is there a way to add one without recreating the entire block.
Probably not. If there were, it would be via the block's MY pseudoclass
and be subject to the same "compile-time modifications only" constraints
as other up-scope lexical manipulations.
> When you say inheritence (which implies a sub)
....implies a method. Not the same thing in Perl 6.
> not inheriting only applies to the outer-most scope - the sub scope -
> currect? Any container blocks
> should still have their full semantics preserved, so that an embedded
> while block, for instance, would still have its corresponding LAST
Of course.
> If that were the case, could you then get around the inheritence issue
> by enclosing the entire body of the sub inside its own block? (I'm
> not saying that that's a good idea, just asking whether it could be
> done.)
Err. I'm afraid you lost me there. What are you trying to achieve, again?
> sub non_method {
> loop {
> PRE {
> print "PRE\n"; # Is printing a side-effect?
> ...
> }
Printing can be a side effect. For example, your example modifies a
global filehandle.
Damian
