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class Proc

Parent: Object Version: 1.6

Index:

new [ ] arity call

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Proc objects are blocks of code that have been bound to a set of local variables. Once bound, the code may be called in different contexts and still access those variables.

def genTimes(factor)
return Proc.new {|n| n*factor }
end
times3 = genTimes(3)
times5 = genTimes(5)
times3.call(12)	�	36
times5.call(5)	�	25
times3.call(times5.call(4))	�	60

class methods
new	Proc.new [{| | block } ] -> aProc
	Creates a new Proc object, bound to the current context. It may be called without a block only within a method with an attached block, in which case that block is converted to the Proc object. def procFrom   Proc.new end aProc = procFrom { "hello" } aProc.call � "hello"

instance methods
[ ]	prc[ [ params ]* ] -> anObject
	Synonym for Proc.call.
arity	prc.arity -> anInteger
	Returns the number of arguments required by the block. If the block takes no arguments, returns -1. If it takes one argument, returns -2. Otherwise, returns a positive argument count unless the last argument is prefixed with *, in which case the argument count is negated. The number of required arguments is anInteger for positive values, and ( anInteger +1).abs otherwise. Proc.new {||}.arity � 0 Proc.new {|a|}.arity � -1 Proc.new {|a,b|}.arity � 2 Proc.new {|a,b,c|}.arity � 3 Proc.new {|*a|}.arity � -1 Proc.new {|a,*b|}.arity � -2
call	prc.call( [ params ]* ) -> anObject
	Invokes the block, setting the block's parameters to the values in params using the same rules as used by parallel assignment. Returns the value of the last expression evaluated in the block. aProc = Proc.new {|a, *b| b.collect {|i| i*a }} aProc.call(9, 1, 2, 3) � [9, 18, 27] aProc[9, 1, 2, 3] � [9, 18, 27]

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