深入理解運算原理｜從簡單的機器到無所不能的程式

只想加入運算能力

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#<struct PDAConfiguration state=2, stack=#<Stack (a)bba$>>,

#<struct PDAConfiguration state=3, stack=#<Stack ($)>>

}>

最後是直接測試字串的

NPDADesign

類別：

class NPDADesign < Struct.new(:start_state, :bottom_character,

:accept_states, :rulebook)

def accepts?(string)

to_npda.tap { |npda| npda.read_string(string) }.accepting?

end

def to_npda

start_stack = Stack.new([bottom_character])

start_configuration = PDAConfiguration.new(start_state, start_stack)

NPDA.new(Set[start_configuration], accept_states, rulebook)

end

end

現在可以檢測我們的 NPDA 真的能識別回文：

>> npda_design = NPDADesign.new(1, '$', [3], rulebook)

=> #<struct NPDADesign …>

>> npda_design.accepts?('abba') ...