blob: c69cd125eef91152fd87717f278dd51c4125c99b (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
|
class UncaughtThrowError < ArgumentError
attr_reader :_tag, :_val
def initialize(tag, val)
@_tag = tag
@_val = val
super("uncaught throw #{tag.inspect}")
end
end
module Kernel
def catch(tag=Object.new, &block)
# A double closure is required to make the nested `catch` distinguishable
# and because `break` goes back to `proc->upper`.
-> { -> { block.call(tag) }.call }.call
end
def throw(tag, val=nil)
__throw(tag, val)
raise UncaughtThrowError.new(tag, val)
end
__preserve_catch_method
end
|
