PEG for Python style indentation
问题 How would you write a Parsing Expression Grammar in any of the following Parser Generators (PEG.js, Citrus, Treetop) which can handle Python/Haskell/CoffeScript style indentation: Examples of a not-yet-existing programming language: square x = x * x cube x = x * square x fib n = if n <= 1 0 else fib(n - 2) + fib(n - 1) # some cheating allowed here with brackets Update: Don't try to write an interpreter for the examples above. I'm only interested in the indentation problem. Another example