Karel For Synthesis

Parser and executor for Karel. Based almost entirely on Nearai's code with some modifications.

Usage

To use the executor, run

from karel_for_synthesis import execute

result = execute(program, input_grid, record_trace=True)

You can also parse and unparse programs by using the parse and unparse commands.

Outputs

This will give you an ExecutionResult object, with the following structure

• ExecutionResult
  • .result: the output grid, or None if there was an error
  • .trace: the output trace. None if record_trace=False is passed
    • .grids: the grids at every timestep in the execution of the program
    • .events: a series of KarelEvent objects
      • .timestep: grids[timestep] corresponds to the grid after this timestep
      • type: the token being executed
      • span: (i, j) for the first and last tokens corresponding to this block
      • cond_span: (i, j) for the first and last tokens contained in the conditional expression if one exists or None otherwise
      • cond_value: the value of the conditional expression or number of remaining iterations
      • success: False if the action failed or the loop repeats forever

Errors

• ExecutorSyntaxException: occurs if the program passed in has invalid syntax
• ExecutorRuntimeException: occurs if the program passed in has an error in executing and record_trace=False is passed