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|
=begin
output:
A
ppt.begin
block called 0
B
retrying
ppt.finally
A
ppt.begin
block called 1
B
ppt.end
ppt.finally
comment:
Let B is the block/proc of the current frame (passed to the current function).
Retry unwinds all frames whose call-sites passed B thru and jumps right before the last call-site that passed B thru
(the next call-site on the stack passed different block).
Ensure clauses are called during stack unwinding.
=end
def retry_proc *,&p
if ($i == 0)
puts 'retrying'
$i = $i + 1
retry
end
end
def pass_proc_thru *,&p
puts 'ppt.begin'
yield
retry_proc puts('B'), &p
puts 'ppt.end'
ensure
puts 'ppt.finally'
end
$i = 0;
def retry_target
pass_proc_thru(puts('A')) {
puts "block called #{$i}"
}
end
retry_target
|
