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Simple and elegant string-substitution based esolang 🕷️
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Malady Spyder PetPet

Malady is a string-substitution based esolang. The premise lies in defining rules within the code that are then used to alter the remaining code until no code is left. A Turing Machine can be easily implemented in Malady, thus rendering Malady turing-complete.

How to Install

You can grab a copy of Malady by cloning this repository. Malady requires Python 3 to run. You may also compile Malady by running make && sudo make install, provided you have Cython3 and a C compiler installed on your system.

How to Use

  • A source file in Malady is a sequence of lines of text (a textfile).
  • There are two types of lines in Malady: Rule lines and Text lines.
  • Lines that don't begin with > are considered plain text.
  • Rule lines begin with the character >, and follow the format >conditions|replacements.
    • Each rule occupies one entire line of code.
    • Conditions are comma separated values that must be matched in any non-rule line (or lines) of the source code in order to trigger the rule.
    • If all the condition tokens are found in the source, the replacements are executed.
      • If a condition is preceded by ~, that token will trigger if it ISN'T found in the source.
    • Replacements are comma sepparated oldvalue->newvalue statements.
      • An oldvalue of * matches any character.
  • Execution halts when there are no characters left in the source.


Add the values of A and B together in C:



This Malady interpreter is distributed under the GNU General Public License 3.0. That dancing spider is a Spyder and belongs to Neopets.

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