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class String
# Evaluates a String as a Proc.
#
# xyp = "|x,y| x + y".to_proc
# xyp.class #=> Proc
# xyp.call(1,2) #=> 3
#
# each &"|x| x + 1"
#
# vs.
#
# each{|x| eval "x + 1"}
#
# NOTE: Sure would be nice if this could grab the caller's context!
#
# CREDIT: Trans
def to_proc(context=nil)
if context
if context.kind_of?(Binding) or context.kind_of?(Proc)
Kernel.eval "proc{ #{self} }", context
else #context
context.instance_eval "proc { #{self} }"
end
else
Kernel.eval "proc{ #{self} }" #, Binding.of_caller
end
end
end
__END__
require 'test/unit'
class TestStringConversion < Test::Unit::TestCase
def test_to_proc
assert_nothing_raised { @add = '|x,y| x + y'.to_proc }
assert_equal(4, @add.call(2,2))
@t = 3
@multi = '|y| @t * y'.to_proc(self)
assert_equal(6, @multi.call(2))
x = 4
@div = '|y| x / y'.to_proc(binding)
assert_equal(2, @div.call(2))
end
end
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