60 lines
1.6 KiB
Ruby
60 lines
1.6 KiB
Ruby
module Util
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module List
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# set the next instruction (also aliased as <<)
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# throw an error if that is set, use insert for that use case
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# return the instruction, so chaining works as one wants (not backwards)
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def set_next( nekst )
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raise "Next already set #{@next}" if @next
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@next = nekst
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nekst
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end
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# get the next instruction (without arg given )
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# when given an interger, advance along the line that many time and return.
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def next( amount = 1)
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(amount == 1) ? @next : @next.next(amount-1)
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end
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# set the give instruction as the next, while moving any existing
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# instruction along to the given ones's next.
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# ie insert into the linked list that the instructions form
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# but allowing the instruction to be a list too (ie more than one)
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def insert( instruction )
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raise "circular insert #{instruction}" if instruction == self
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instruction.last.set_next @next
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@next = instruction
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end
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# return last set instruction. ie follow the linked list until it stops
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def last
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code = self
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while( code.next )
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raise "Circular list #{code.class}:#{code}" if code == code.next
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code = code.next
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end
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return code
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end
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# set next for the last (see last)
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# so append the given code to the linked list at the end
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def append( code )
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last.set_next code
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self
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end
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alias :<< :append
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def length
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ret = 0
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self.each { ret += 1}
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ret
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end
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def each(&block)
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block.call(self)
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@next.each(&block) if @next
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end
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end
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end
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