As we discussed in the section on blocks and iterators beginning
on page 38, when a method is called, it may be
associated with a block. Normally, you simply call the block from
within the method using
yield.
def takeBlock(p1)
if block_given?
yield(p1)
else
p1
end
end
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takeBlock("no block")
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� |
"no block"
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takeBlock("no block") { |s| s.sub(/no /, '') }
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� |
"block"
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However, if the last parameter in a method definition is
prefixed with an ampersand, any associated block is converted to a
Proc object, and that object is assigned to the parameter.
class TaxCalculator
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def initialize(name, &block)
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@name, @block = name, block
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end
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def getTax(amount)
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"#@name on #{amount} = #{ @block.call(amount) }"
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end
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end
|
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tc = TaxCalculator.new("Sales tax") { |amt| amt * 0.075 }
|
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tc.getTax(100)
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� |
"Sales tax on 100 = 7.5"
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tc.getTax(250)
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� |
"Sales tax on 250 = 18.75"
|
