66 lines
2.2 KiB
Lua
66 lines
2.2 KiB
Lua
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-- BRAINFUCK interpreter by rnd, 2017
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-- https://en.wikipedia.org/wiki/Brainfuck
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if not ram then
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prog = "+++.>++++++.<[->+<]>."
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ramsize = 10
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maxsteps = 100; step=0; -- for RUN state only
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n = string.len(prog);ram = {};for i = 1, ramsize do ram[i]=0 end -- init ram
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pointer = 1 -- ram pointer
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instruction = 1 -- instruction pointer
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self.spam(1)
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RUNNING = 1; END = 2; RUN = 3;
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state = RUNNING
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get_ram = function() msg = "" for i = 1,ramsize do msg = msg .. ram[i] .. "," end return msg end
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cmdset = {
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[">"] = function() pointer = pointer + 1; if pointer > ramsize then pointer = 1 end end,
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["<"] = function() pointer = pointer - 1; if pointer > ramsize then pointer = 1 end end,
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["+"] = function() ram[pointer]=ram[pointer]+1 end,
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["-"] = function() ram[pointer]=ram[pointer]-1 end,
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["."] = function() say(ram[pointer]) end,
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[","] = function() ram[pointer] = tonumber(read_text.forward("infotext") or "") or 0 end,
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["["] = function()
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if ram[pointer] == 0 then
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local lvl = 0
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for j = instruction, n, 1 do
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if string.sub(prog,j,j) == "]" then lvl = lvl - 1 if lvl == 0 then
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self.label("JMP " .. j ) instruction = j return
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end end
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if string.sub(prog,j,j) == "[" then lvl = lvl + 1 end
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end
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end
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end,
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["]"] = function()
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if ram[pointer] ~= 0 then
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local lvl = 0
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for j = instruction, 1, -1 do
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if string.sub(prog,j,j) == "]" then lvl = lvl - 1 end
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if string.sub(prog,j,j) == "[" then lvl = lvl + 1 if lvl == 0 then
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self.label("JMP " .. j ) instruction = j return
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end end
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end
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end
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end,
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}
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end
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-- EXECUTION
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if state == RUNNING then
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c = string.sub(prog,instruction,instruction) or "";
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if c and cmdset[c] then cmdset[c]() end
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self.label("ins ptr " .. instruction .. ", ram ptr " .. pointer .. ": " .. ram[pointer] .. "\n" .. string.sub(prog, instruction).."\n"..get_ram())
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instruction = instruction + 1; if instruction > n then state = END end
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-- RUN THROUGH
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elseif state == RUN then
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while (step<maxsteps) do
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step = step + 1
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c = string.sub(prog,instruction,instruction) or "";
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if c and cmdset[c] then cmdset[c]() end
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instruction = instruction + 1; if instruction > n then self.label("ram : " .. get_ram()) step = maxsteps state = END end
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end
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end
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