treetop

I've got a file that I want to parse with Treetop. If I wanted to parse the entire thing, I'd use rule document category_listing* end I don't really want to read the entire file into memory at once. I know I can set up the parser to parse one category_listing at a time (using #consume_all_input = false and #root = :category_listing ), which is half the problem. However, it looks like #parse expects to be passed a String (and it certainly fails when I try to pass it a File ), which makes the idea of reading and parsing category_listing by category_listing sound like a PITA. Can Treetop only be

I'm trying to use Treetop to parse an ERB file. I need to be able to handle lines like the following: <% ruby_code_here %> <%= other_ruby_code %> Since Treetop is written in Ruby, and you write Treetop grammars in Ruby, is there already some existing way in Treetop to say "hey, look for Ruby code here, and give me its breakdown" without me having to write out separate rules to handle all parts of the Ruby language? I'm looking for a way, in my .treetop grammar file, to have something like: rule erb_tag "<%" ruby_code "%>" { def content ... end } end Where ruby_code is handled by some rules

How would I do something like this in Treetop? /.+?;/ It seems like the only way is to do: [^;]+ ';' Which is kind of ugly.. any other way? .+? doesn't seem to work.. PEGs are greedy and blind by default, that means they eat as much input as they can and they do not consider what comes afterwards: S <- P1* P2 (greedy, blind) That can be considerably easy fixed though by making use of the ordered choice (and without using lookaheads): S <- P1 S / P2 (greedy, non-blind) S <- P2 / P1 S (lazy, non-blind) Well, I learnt PEGs are greedy, and there's no way around it. Lookaheads can be used to mimic

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 might be parsing the following: foo bar = 1 baz = 2 tap zap = 3 # should yield (ruby style hashmap): #