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A Brainfuck interpreter in RegEx only (using Find/Replace)
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A Brainfuck interpreter in RegEx only (using Find/Replace). This demonstrates, that RegEx in combination with Find/Replace is Turing complete.


Use any Editor that can find/replace with RegEx Syntax. I tested this on Notepad++, but since I only used Perl RegEx Syntax, it should also work with other applications. Create a new file and add the Brainflakes source code on the first line. It must contain a sequence of only the 8 coding BF characters, all on the first and only line, like it's done HelloWorld.b

Use "find and replace" in RegEx mode with the "find" parameter from Find.txt and the "replace" parameter from Replace.txt. Click “replace all” once. This will set up the environment (now 4 lines of code). If the BF code demands input, you have to write it on line 2, AFTER the ‘|’ character.

Now click “replace all” many, many times. Or if you don't want to get cramps, use the keyboard shortcut for “replace all” (in the German Version of Notepad++ its alt+T).

The Interpreter will only stop:

  • When more user input is needed
  • When a HALT state is reached (end of code). It will remove everything except the output and stop replacing.
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