Before talk?
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- non node-instantiating expressions extend their results with inline modules
- allow load_grammar and require statements at the top of treetop files
- deal with facets versioning issue



Function application... the left-recursion problem
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f g x

rule expression
  application / function / variable
end

rule application
  expression space expression
end

Function application... how can we avoid left recursion?
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rule expression
  application / function / variable
end

rule application
  operator space expression
end

rule operator
  function / variable
end