class Crapshoot::Evaluator
Stack-based calculator that relies on the “eval” method of tokens.
Public Instance Methods
evaluate(tokens)
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# File lib/crapshoot/evaluator.rb, line 4 def evaluate(tokens) @stack = [] @tokens = tokens.dup until @tokens.empty? step end raise "Stack has too many entries: #{@stack.inspect}" unless @stack.length == 1 return @stack[0] end
step()
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# File lib/crapshoot/evaluator.rb, line 16 def step candidate = @tokens.shift result = candidate.eval @stack @stack.push result end