117 lines
2.6 KiB
Plaintext
117 lines
2.6 KiB
Plaintext
local ds = require("DataStructures")
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local Dictionary, Stack, WordInfo, State = ds.Dictionary, ds.Stack, ds.WordInfo, ds.State
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-- helper functions
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function areNumbers(a: any, b: any): boolean
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return a is number and b is number
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end
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function getActiveDataStack(state: State): Stack
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return state.activeDataStack
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end
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function isNumber(token: string): boolean
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if tonumber(token) ~= nil then
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return true
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else
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return false
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end
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end
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function isWhitespace(chr: string): boolean
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return (chr == " " or
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chr == "\t" or
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chr == "\r" or
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chr == "\n" or
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chr == "\v" or
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chr == "\f")
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end
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function popTwoOperands(state: State): any, any
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local stack = getActiveDataStack(state)
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local b: any = stack:pop()
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local a: any = stack:pop()
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return a, b
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end
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-- Mathematical operations
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function add(state: State)
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local a, b = popTwoOperands(state)
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if areNumbers(a,b) then
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local c = (a as number) + (b as number)
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getActiveDataStack(state):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 sub(state: State)
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local a, b = popTwoOperands(state)
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if areNumbers(a, b) then
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local c = (a as number) - (b as number)
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getActiveDataStack(state):push(c)
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else
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error("invalid operands for sub operation!")
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end
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end
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function mul(state: State)
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local a, b = popTwoOperands(state)
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if areNumbers(a, b) then
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local c = (a as number) * (b as number)
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getActiveDataStack(state):push(c)
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else
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error("invalid operands for mul operation!")
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end
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end
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function div(state: State)
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local a, b = popTwoOperands(state)
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if areNumbers(a, b) then
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local c = (a as number) / (b as number)
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getActiveDataStack(state):push(c)
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else
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error("invalid operands for div operation!")
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end
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end
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-- I/O operations
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function dot(state: State)
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local out = state.activeDataStack:pop()
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print(out)
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end
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function skipWhitespace(state: State)
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local chr = state.activeInputStream:readCurrentCharacter()
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while (isWhitespace(chr)) do
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chr = state.activeInputStream:advanceOffset()
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end
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end
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function parseToken(state: State): string
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local chr = state.activeInputStream:readCurrentCharacter()
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local token = ""
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while(not isWhitespace(chr)) do
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token = token..chr
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chr = state.activeInputStream:advanceOffset()
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end
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end
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local CoreWords = Dictionary:new()
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local AddInfo = WordInfo:new(add, false)
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local SubInfo = WordInfo:new(sub, false)
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local MulInfo = WordInfo:new(mul, false)
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local DivInfo = WordInfo:new(div, false)
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CoreWords:define("+", AddInfo)
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CoreWords:define("-", SubInfo)
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CoreWords:define("*", MulInfo)
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CoreWords:define("/", DivInfo)
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return CoreWords
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