52 lines
930 B
Plaintext
52 lines
930 B
Plaintext
local ForthStack = {}
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global type Stack = record
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contents: {any}
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top: number
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push: function(Stack, any)
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pop: function(Stack)
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new: function(Stack): Stack
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end
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function Stack:push(val: any)
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self.top = self.top + 1
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table.insert(self.contents,val)
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end
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function Stack:pop(): any
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self.top = self.top -1
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if self.top < 0 then
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error("Stack underflow")
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end
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return table.remove(self.contents)
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end
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local stack_mt = {__index = Stack}
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function Stack:new(): Stack
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return setmetatable({contents = {}, top = 0} as Stack, stack_mt)
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end
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-- operations
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function ForthStack.add(stack: Stack)
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local a: any =stack:pop()
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local b: any=stack:pop()
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if a is number and b is number then
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local c=a+b
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stack:push(c)
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else
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error("invalid operands for add operation!")
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end
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end
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function ForthStack.dot(s: Stack)
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print(s:pop())
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end
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local s = Stack:new()
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s:push(1)
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s:push(4)
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ForthStack.add(s)
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print(ForthStack.dot(s))
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return ForthStack
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