An interpreter for the Shakespeare Programming Language.

shakespeare interpreter
pip install shakespearelang==0.3.0



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An interpreter for the Shakespeare Programming Language, implemented in Python.

What is the Shakespeare Programming Language?

The Shakespeare Programming Language (SPL) is a programming language with source code that looks like Shakespeare's plays. The language is Turing complete, so theoretically just as powerful as any other language. It's a lot of fun to write but not practical for any large projects. More info can be found on Wikipedia.

Note: Shakespeare's actual plays are not valid SPL. SPL does not aim to provide backwards compatibility with legacy code written ~400 years ago.

What is this project?

This is an interpreter I wrote for SPL. It's written in Python. The aim is to help programmers better understand how their SPL code is executing, with features like a console and debugging. All previous implementations of SPL were source-to-source-compilers, which makes an already confusing language even harder to follow.

What state is this project in?

I haven't written any tests yet, but it will probably run any valid SPL program. The console and debugger are both working.


pip install shakespearelang
# Or however else you install things. You do you.




shakespeare run my-program.spl
shakespeare debug my-program.spl
shakespeare console # or just "shakespeare" unadorned


In the console, you'll essentially write an SPL program/play line-by-line, defining your characters first.

Input to the console can be any of these:

  • Entrances, exits, and spoken lines as they would normally appear in a play/program.
  • Sentence(s) spoken by the last character who was speaking. For example, if the previous line was Juliet: You are a fat pig., the sentences Remember thyself! You are a fat fat pig. could be tacked onto the previous line.
  • Expressions (standalone values without assignment), spoken implicitly by the last speaking character or with an explicit character: Juliet: The difference between thyself and a fat pig. These cannot end with periods.
  • A character's name, which displays that character's stack and current value.
  • stage, which displays which characters are on and off stage.
  • exit or quit, which will leave the console.


Debugging and running are identical for many programs. In order to utilize the debugging feature, you'll need to place a breakpoint somewhere in your SPL code using the following stage direction:

[A pause]

When the debugger hits this stage direction, it will pause execution of the play/program and enter a REPL. This is just like the standalone console, except you can use the next command to step forward, and the continue command to exit the REPL and continue running the program/play.


The interpreter's run_play method can be used to run an entire play, and there are other methods for evaluating expressions and questions, running events and sentences, and adding characters. These all can take either a string or an AST (the former being easier to get from a user, the latter being easier to generate in code). These are named how you might expect them to be named. See for a more complex example of deeply interfacing with the interpreter from Python.

Note: It is recommended to do any necessary parsing using interpreter.parser.parse() instead of using the parser directly, as the interpreter requires a specific setting on the parser to work correctly. Otherwise, information on parse() can be found at the Grako docs.