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<p>Early (outdated) documentation attempt here:</p><p><a href="https://docs.google.com/document/d/1DRN-tBIqhqVVyoHIDs7CMkduBFk-vqd_958ojeIBLHQ/edit">https://docs.google.com/document/d/1DRN-tBIqhqVVyoHIDs7CMkduBFk-vqd_958ojeIBLHQ/edit</a></p><p> </p><p> </p><h1>Notes from working with existing AST</h1><ul><li>Blocks<ul><li>Inconsistent treatment of empty blocks<ul><li>(let [x 1]) has four environments of interest: before the let form, at x's initializer, after x is 1, and after the let form. For an empty block, there is no where to get an environment with x in the locals.</li><li>Would be nice to have an explicit nil :constant node for empty blocks</li></ul></li><li>Synthetic blocks<ul><li>Would be a place to hang that :env</li><li>Could disallow special forms other than 'do from having blocks. Change (let* [x 1] 2 3) to (let* [x 1] (do 2 3))</li><li>let and letfn don't expose a :body-env, but try's catch does! would prefer explicit blocks nodes</li></ul></li><li>(conj (vec statements ret)) pattern spills into client code<ul><li>Inconsistent here too. Forcing children to vectors causes heap to fall over for cljs.core on my box</li><li>Should not allow lazy structures to persist between passes</li></ul></li></ul></li><li>:children key duplication<ul><li>Detailed discussion here: <a href="http://dev.clojure.org/display/design/AST+children">http://dev.clojure.org/display/design/AST+children</a> (fold that into this page?)</li></ul></li><li>No root AST node type<ul><li>Need a place to hang top-level info. File names, source data, etc.</li></ul></li><li>loop yields :let op<ul><li>Shares a lot of implementation details, but are genuinely distinct ops</li><li>Straight forward fix to add another op type and to call parameterized implementations</li><li>Allows more flexibility in representing bindings</li></ul></li></ul>