Execute Brain****/Lua: Difference between revisions

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Fixed syntax highlighting.
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{{implementation|Brainf***}}{{collection|RCBF}}
 
{{incorrect|Lua|Instead of jumping to the *next* close bracket when reaching a [ and memory[pointer] == 0, it should jump to the next *matching* close bracket such that embedded loops work}}
An implementation of a Brainf*** interpreter in [[Lua]].
<langsyntaxhighlight lang="lua">memory = {0} --memory is bounded on one side, at 1
 
program = io.read("*all") --loads an entire program at once, must not contain newlines
 
pointer = 1
Line 30:
if memory[pointer] ~= 0 then
table.insert(retpoints, instruction)
else -- if the memory at the pointer is zero, jump to the nextmatching close bracket
local b = 1 -- b stores number of unclosed brackets (when b == 0 the match has been found)
while program:sub(instruction, instruction) ~= "]" do
while instruction <= #program and b ~= 0 do
instruction = instruction + 1
while if program:sub(instruction, instruction) ~== "][" dothen
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 memory[pointer]#retpoints ~=> 0 then
if memory[pointer] ~= 0 then
instruction = retpoints[#retpoints]
else
table.remove(retpoints)
end
else
error"Missing '['!"
table.remove(retpoints)
end
end,
Line 53 ⟶ 66:
if instr then instr() end
instruction = instruction + 1
end</langsyntaxhighlight>
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