0.1.15 docs





    Jan 26, 2018

    Zach Tellman
    San Francisco, CA


    Index of all namespaces

    The README below is fetched from the published project artifact. Some relative links may be broken.
    Walker is my name
    and I am the same.
    Riddley Walker.
    Walking my riddels
    where ever theyve took me
    and walking them now
    on this paper the same.

    from Riddley Walker by Russell Hoban

    Code may be data, but only some of that data is executable. If we want to perform a pervasive code transformation, using something like clojure.walk presents a few problems:

    • binding forms are treated the same as actual expressions
    • clojure.walk/macroexpand-all will pass in a nil &env to all macros
    • macroexpansion doesn’t expand inlined functions

    This means that transforms that we intend to apply to expressions may have unintended consequences on a fn, let, or case form. It also means that any macro which relies on &env will not compose with our transformation. Finally, if inlined functions aren’t expanded, certain transformations will break.


    Build Status

    [riddley "0.1.15"]

    Riddley provides a correct riddley.walk/macroexpand-all, which preserves the binding information in &env and expands inlined functions, and riddley.walk/walk-exprs, which is a general mechanism for code walking and transformation.

    walk-exprs takes two arguments, a predicate for whether it should transform the sub-form, and a handler for doing the transformation.

    riddley.walk> (walk-exprs number? inc '(let [n 1] (+ n 1)))
    (let* [n 2] (. clojure.lang.Numbers (add n 2)))

    Notice that walk-exprs implicitly macroexpands the form, including the inline form for +. Unlike clojure.walk, if handler is called, sub-forms will not be walked. The handler function is responsible for recursively calling walk-exprs on the form it’s handed.

    Access to &env is available via (riddley.compiler/locals) if you need it as part of your transformation.

    Full documentation can be found here.


    Copyright © 2013 Zachary Tellman

    Distributed under the MIT License.