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@mtnygard

mtnygard/README.md

Last active May 9, 2018
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What would you like to do?
Create a dependency matrix of Clojure namespaces.

The dependency matrix shows the strength of coupling at a var-by-var level between namespaces.

If you pull the CSV output into a spreadsheet, the numbers in the cells show how many var->var dependencies there are between the namespaces.

If you want to just look at namespace->namespace dependencies (e.g., to create a visualization) then just consider any cell > 0 as a dependency.

(ns assess
(:require [clojure.tools.analyzer.jvm :as ana.jvm]
[clojure.java.io :as io]
[clojure.string :as str]
[clojure.pprint :as pp])
(:import java.io.PushbackReader))
;;; ========================================
;;; Utility functions
(defn- cross [f xs]
(for [x xs
y xs]
(f x y)))
(defn- map-vals [f m]
(with-meta
(zipmap (keys m) (map f (vals m)))
(meta m)))
(defn- remove-vals [pred m]
(map-vals #(remove pred %) m))
(defn- count-by [f coll]
(map-vals count (group-by f coll)))
;;; This postwalk is specific to the return value produced by
;;; clojure.tools.analyzer.jvm
(defn postwalk [ast f]
(f (reduce
(fn [acc key]
(let [value (get ast key)]
(if (vector? value)
(assoc acc key (doall (mapv (fn [node] (postwalk node f)) value)))
(assoc acc key (postwalk value f)))))
ast
(:children ast))))
;;; Postwalk an AST, extract references to vars.
;;; Meant for use on a top-level form like a def or defn
(defn var-references [ast]
(let [refs (atom #{})]
(postwalk
ast
(fn [n]
(when-let [v (:var n)]
(swap! refs conj v))
n))
@refs))
(defn- ns-loaded? [s]
(some #{s} (map #(.name %) (all-ns))))
(defn- ns-loaded! [s]
(when-not (ns-loaded? s)
(require s)))
;;; Does this AST node represent an `ns` form? If so, return the new
;;; namespace symbol
(defn- nsdecl? [n]
(and
(= :do (-> n :op))
(= :invoke (-> n :statements first :op))
(= 'clojure.core/in-ns (-> n :statements first :form first))
(-> n :statements first :form second second)))
;;; If this is a def, return the var it defines
(defn top-level-def [n]
(when (= :def (:op n))
(:var n)))
;;; Locate all var refs inside a sequence of forms.
;;; When the forms change namespaces, follow those namespace changes
;;; so the right aliases are in scope. When we encounter namespaces
;;; that aren't yet loaded, require them.
;;; This means the analysis only works when 100% of source modules
;;; compile!
;;; Returns a map of var to set of vars. Takes a sequence of forms, as
;;; you would get from `read-all-forms` below.
(defn- var-refs [forms]
(loop [ns-for-next-form *ns*
var-refs {}
forms forms]
(if-let [[f & rest] forms]
(let [node (binding [*ns* ns-for-next-form]
(ana.jvm/analyze f))
new-var (top-level-def node)
new-ns (nsdecl? node)]
(when new-ns
(ns-loaded! new-ns))
(recur
(or new-ns ns-for-next-form)
(if new-var
(assoc var-refs new-var (disj (var-references node) new-var))
var-refs)
rest))
var-refs)))
;;; ========================================
;;; Analyzing the results
(defn- var-ns [v] (.name (.ns v)))
(defn- ns-starts-with? [s ns]
(str/starts-with? (str ns) s))
;;; Customize this list to the specific project.
(def ^:private external-namespaces
["clojure"
"medley"
"gloss"
"camel-snake-kebab"
"automat"
"plumbing"
"schema."
"com.stuartsierra"
"cemerick"
"byte-streams"
"ring"
"bidi"
"compojure"
"buddy"
"endophile"
"cheshire"
"honeysql"
"pantomime"
"modular"
"org.httpkit"
"clj-time"
"redsys-clj"
"clj-uuid"
"postal"
"selmer"
"zeromq"])
(def ^:private external?
(apply some-fn (map #(partial ns-starts-with? %) external-namespaces)))
(defn- all-ns-in-depmaps [depmaps]
(reduce into #{}
(for [depmap depmaps
[from-var to-vars] depmap
to-ns (map var-ns to-vars)
:when (not (external? to-ns))]
(hash-set (var-ns from-var) to-ns))))
(defn- empty-coupling-list [depmaps]
(->> depmaps
all-ns-in-depmaps
(cross #(hash-map [%1 %2] 0))
(apply merge)))
(defn unnest [m]
(reduce-kv
(fn [l k v]
(conj l (assoc v :name k)))
[]
m))
;; Receives list of map from var to set of var
;; emits map of {[from-ns to-ns] strength}
(defn coupling-strength [depmaps]
(apply merge-with +
(empty-coupling-list depmaps)
(for [depmap depmaps
[from-var to-vars] depmap
:let [to-nses (count-by var-ns to-vars)]
[to-ns strength] to-nses
:when (not (external? to-ns))]
{[(var-ns from-var) to-ns] strength})))
;; Receives list of map from var to set of variable
;; Emits list of {:name sym sym1 int sym2 int sym3 int,,,}
;; where the first symbol is the "from" and the sym1, sym2, sym3
;; values are the strength of coupling between "from" and "sym1" etc.
(defn coupling-matrix [depmaps]
(let [all-known-nses (all-ns-in-depmaps depmaps)
empty-row (zipmap all-known-nses (repeat 0))
empty-matrix (zipmap all-known-nses (repeat empty-row))
nested-map (reduce
(fn [cmap [from-ns to-ns st]]
(let [oldrow (get cmap from-ns empty-row)]
(assoc cmap from-ns (update oldrow to-ns #(+ % st)))))
empty-matrix
(for [depmap depmaps
[from-var to-vars] depmap
:let [to-nses (count-by var-ns to-vars)]
[to-ns strength] to-nses
:when (not (external? to-ns))]
[(var-ns from-var) to-ns strength]))]
(unnest nested-map)))
;;; ========================================
;;; Deal with source files
(defn read-all-forms
[file]
(let [rdr (-> file io/file io/reader PushbackReader.)]
(loop [forms []]
(let [form (try (read rdr) (catch Exception e nil))]
(if form
(recur (conj forms form))
forms)))))
(defn- clojure? [f]
(or (str/ends-with? (.getName f) ".clj")
(str/ends-with? (.getName f) ".cljc")))
(defn- srcs-in-path [srcdir]
(->> srcdir
io/file
file-seq
(filter clojure?)))
;;; ========================================
;;; Driver functions
(defn all-var-refs-in-path
[srcdir]
(for [s (srcs-in-path srcdir)]
(with-meta (var-refs (read-all-forms s)) {:src (.getPath s)})))
(defn- print-csv
[ks rows]
(let [fmt-row (fn [row] (apply str (interpose "," row)))]
(println (fmt-row ks))
(doseq [row rows]
(println (fmt-row (mapv #(get row %) ks))))))
(defn analyze-to-csv
[srcdir outfile]
(with-open [writer (java.io.PrintWriter. (io/file "all-ns-refs.csv"))]
(binding [*print-length* nil
*out* writer]
(let [alldeps (all-var-refs-in-path "src")
mtx (coupling-matrix alldeps)
mtx (sort-by :name mtx)
cols (sort (filter #(not= % :name) (keys (first mtx))))]
(print-csv (list* :name cols) mtx)))))
{:deps
{org.clojure/tools.analyzer.jvm {:mvn/version "0.7.2"}}}
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