 --[[

  Brainfuck, written by John.
  
  Brainfuck is an esoteric programming language, designed to be as inconvenient as possible, hence the
  name Brainfuck. It essentially manipulates an infinite number of cells, each of which hold an 8-bit
  integer, and a pointer. The pointer 
  
  
  INSTRUCTIONS:
  
  In the input box, type in these characters:
  
  > - Move the pointer right
  < - Move the pointer left
  + - Increment the byte at the pointer by one
  - - Decrement the byte at the pointer by one
  . - Output the byte at the pointer
  , - 
  
  
  ADDITIONAL NOTES:
  
  - Characters not in this list will not be read and can be used as comments, and whitespace can be used.
  - Each cell can hold a value from 0 to 255. Go over or under, and it will overflow.
  
]]--

local input = io.read("*a")

-- look for >

local right = 0

for i = 1, #input do
  if input:sub(i, i) == ">" then
    right = right + 1
  end
end

-- look for <

local left = 0

for i = 1, #input do
  if input:sub(i, i) == "<" then
    left = left + 1
  end
end

-- look for +

local increment = 0

for i = 1, #input do
  if input:sub(i, i) == "+" then
    increment = increment + 1
  end
end

-- look for -

local decrement = 0

for i = 1, #input do
  if input:sub(i, i) == "-" then
    decrement = decrement + 1
  end
end

created 1 year ago

Lua online compiler

Write, Run & Share Lua code online using OneCompiler's Lua online compiler for free. It's one of the robust, feature-rich online compilers for Lua language, running the latest Lua version 5.4. Getting started with the OneCompiler's Lua editor is easy and fast. The editor shows sample boilerplate code when you choose language as Lua and start coding.

Taking inputs (stdin)

OneCompiler's Lua online editor supports stdin and users can give inputs to programs using the STDIN textbox under the I/O tab. Following is a sample Lua program which takes name as input and prints hello message with your name.

name = io.read("*a")
print ("Hello ", name)

About Lua

Lua is a light weight embeddable scripting language which is built on top of C. It is used in almost all kind of applications like games, web applications, mobile applications, image processing etc. It's a very powerful, fast, easy to learn, open-source scripting language.

Syntax help

Variables

By default all the variables declared are global variables
If the variables are explicitly mentioned as local then they are local variables.
Lua is a dynamically typed language and hence only the values will have types not the variables.

Examples

-- global variables
a = 10

-- local variables

local x = 30

Value Type	Description
number	Represents numbers
string	Represents text
nil	Differentiates values whether it has data or not
boolean	Value can be either true or false
function	Represents a sub-routine
userdata	Represents arbitary C data
thread	Represents independent threads of execution.
table	Can hold any value except nil

Loops

1. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while(condition)
do
--code
end

2. Repeat-Until:

Repeat-Until is also used to iterate a set of statements based on a condition. It is very similar to Do-While, it is mostly used when you need to execute the statements atleast once.

repeat
   --code
until( condition )

3. For:

For loop is used to iterate a set of statements based on a condition.

for init,max/min value, increment
do
   --code
end

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increase re-usuability and modularity.

optional_function_scope function function_name( argument1, argument2, argument3........, argumentn)
--code
return params with comma seperated
end