Execute Brain****/Lua: Difference between revisions
Content added Content deleted
(fixed missing then) |
m (Changed `io.read()` to `io.read("*all")` (reads the entire input until EOF, not just one line).) |
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<lang lua>memory = {0} --memory is bounded on one side, at 1 |
<lang lua>memory = {0} --memory is bounded on one side, at 1 |
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program = io.read() |
program = io.read("*all") |
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pointer = 1 |
pointer = 1 |
Revision as of 18:07, 1 September 2016
Execute Brain****/Lua is an implementation of Brainf***.
Other implementations of Brainf***.
Execute Brain****/Lua is part of RCBF. You may find other members of RCBF at Category:RCBF.
An implementation of a Brainf*** interpreter in Lua. <lang lua>memory = {0} --memory is bounded on one side, at 1
program = io.read("*all")
pointer = 1
instruction = 1
retpoints = {}
functions = { [">"] = function()
pointer = pointer + 1 if not memory[pointer] then memory[pointer] = 0 end
end, ["<"] = function()
if pointer == 1 then error"Memory out-of-bounds!" end pointer = pointer - 1
end, ["+"] = function()
memory[pointer] = memory[pointer] + 1
end, ["-"] = function()
memory[pointer] = memory[pointer] - 1
end, ["["] = function()
if memory[pointer] ~= 0 then table.insert(retpoints, instruction) else -- if the memory at the pointer is zero, jump to the matching close bracket local b = 1 -- b stores number of unclosed brackets (when b == 0 the match has been found) while instruction <= #program and b ~= 0 do instruction = instruction + 1 if program:sub(instruction, instruction) == "[" then b = b + 1 elseif program:sub(instruction, instruction) == "]" then b = b - 1 end end if b ~= 0 then error"Missing ']'!" end end
end, ["]"] = function()
if #retpoints > 0 then if memory[pointer] ~= 0 then instruction = retpoints[#retpoints] else table.remove(retpoints) end else error"Missing '['!" end
end, ["."] = function()
io.write(string.char(memory[pointer]))
end, [","] = function()
memory[pointer] = io.read():byte()
end} while instruction <= #program do
local instr = functions[program:sub(instruction,instruction)] if instr then instr() end instruction = instruction + 1
end</lang>