Sha256: 17cd2ce742c46a87b3218ef800356e5c2a5d5bfd3ddf88cceca2864432742d80
Contents?: true
Size: 984 Bytes
Versions: 10
Compression:
Stored size: 984 Bytes
Contents
#START:stack
class CatchStack
Frame = Struct.new(:symbol, :cc)
def stack
Thread.current[:catch_stack] ||= []
end
def wrap(symbol, cc)
stack << Frame.new(symbol, cc)
begin
yield
ensure
stack.pop
end
end
def find_continuation_for(symbol)
stack.pop until stack.empty? || stack.last.symbol == symbol
if stack.empty?
fail NameError, "uncaught throw `#{sym}'"
else
stack.pop.cc
end
end
end
#END:stack
#START:CC
module CC
CATCH_STACK = CatchStack.new
def self.catch(sym)
callcc do |cc|
CATCH_STACK.wrap(sym, cc) do
yield
end
end
end
def self.throw(sym, value=nil)
cc = CATCH_STACK.find_continuation_for(sym)
cc.call(value)
end
end
#END:CC
#START:body
def test_method
CC.throw(:x, "thrown X") if rand < 0.5
end
result = CC.catch(:x) do
test_method
"normal exit"
end
puts "Result is #{result}"
#END:body
Version data entries
10 entries across 10 versions & 5 rubygems