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Rethink the the parser/compiler architecture #37

rstacruz opened this Issue Jun 9, 2011 · 1 comment


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rstacruz commented Jun 9, 2011

Currently, the procedures that translate a Node into a string (for (x;y;z) { a } => x; while y; a; z) is tied too much into the procedures that transform a Node into another Node (if typeof x != 'undefined' => unless x?). I think they should be decoupled to make more optimizations easier and more maintainable.

Currently, js2coffee works like this:

  1. Ask Narcissus to build a tree of the source JS
  2. Js2coffee's Builder traverses this tree and builds a CS source from it

It should be more like:

  1. Ask Narcissus to build a tree of the source JS
  2. Transform this tree by traversing it and making optimizations along the way (+++)
  3. Js2coffee's Builder traverses this new tree and builds a CS source from it

During that transformation step, that's when the Coffee'isms like the following should be made:

  • ifs should be made unless when the condition can be negated simply
  • typeof x == 'undefined' should be made into existential checks
  • switch nodes should be ensured that there aren't unnecessary break statements
  • when A: when B: should be consolidated to a compound when A, B:
  • etc...

michaelficarra commented Jun 9, 2011

Yep , you must separate the AST manipulation step from the compilation step. You should probably continue taking manipulation passes over the tree until you reach a fixpoint. +1.

@rstacruz rstacruz added a commit that referenced this issue Jun 10, 2011

@rstacruz rstacruz Separate the tree manipulation step from the build step. See #37. Als…
…o, fix 'x.prototype.y' to be 'x::y' instead of 'x::.y'; and omit many unneeded parentheses in certain cases.

@rstacruz rstacruz closed this Jun 10, 2011

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