Port dependency, parse, and track to .cljc

Stuart Sierra · Stuart Sierra · commit 9a07ad48ab59 · 2015-07-17T16:52:41.000-04:00
Affects these namespaces:

- clojure.tools.namespace.dependency
- clojure.tools.namespace.parse
- clojure.tools.namespace.track

With minor changes, these files are platform-neutral.

c.t.n.dependency is a general-purpose library which has many
applications outside of tools.namespace.

The uses for c.t.n.parse and c.t.n.track in ClojureScript are less
apparent, but they are easy to port. Perhaps by porting other namespaces
it will be possible in the future to have a version of c.t.n.repl that
works on non-JVM platforms.
diff --git a/pom.xml b/pom.xml
@@ -10,6 +10,20 @@
     <version>0.1.2</version>
   </parent>
 
+  <dependencies>
+    <dependency>
+      <groupId>org.clojure</groupId>
+      <artifactId>clojure</artifactId>
+      <version>1.7.0</version>
+      <scope>provided</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.clojure</groupId>
+      <artifactId>tools.reader</artifactId>
+      <version>0.10.0-alpha1</version>
+    </dependency>
+  </dependencies>
+
   <properties>
     <clojure.warnOnReflection>true</clojure.warnOnReflection>
   </properties>
@@ -26,4 +40,5 @@
     <url>git@github.com:clojure/tools.namespace.git</url>
     <tag>HEAD</tag>
   </scm>
+
 </project>
diff --git a/src/main/clojure/clojure/tools/namespace/dependency.cljc b/src/main/clojure/clojure/tools/namespace/dependency.cljc
@@ -142,13 +142,16 @@
                (remove-node g' node)
                (clojure.set/union (set more) (set add)))))))
 
+(def ^:private max-number
+  #?(:clj Long/MAX_VALUE
+     :cljs js/Number.MAX_VALUE))
+
 (defn topo-comparator
   "Returns a comparator fn which produces a topological sort based on
   the dependencies in graph. Nodes not present in the graph will sort
   after nodes in the graph."
   [graph]
   (let [pos (zipmap (topo-sort graph) (range))]
     (fn [a b]
-      (compare (get pos a Long/MAX_VALUE)
-               (get pos b Long/MAX_VALUE)))))
-
+      (compare (get pos a max-number)
+               (get pos b max-number)))))
diff --git a/src/main/clojure/clojure/tools/namespace/parse.cljc b/src/main/clojure/clojure/tools/namespace/parse.cljc
@@ -10,24 +10,9 @@
       :doc "Parse Clojure namespace (ns) declarations and extract
   dependencies."}
   clojure.tools.namespace.parse
-  (:require [clojure.set :as set]))
-
-(defn- read-clj
-  "Calls clojure.core/read. If reader conditionals are
-  supported (Clojure 1.7) then adds options {:read-cond :allow}."
-  [rdr]
-  (if (resolve 'clojure.core/reader-conditional?)
-    (read {:read-cond :allow} rdr)
-    (read rdr)))
-
-(defn- force-errors
-  "Forces reader errors to be thrown immediately. Some versions of
-  Clojure accept invalid forms in the reader and only throw an
-  exception when they are printed.
-  See http://dev.clojure.org/jira/browse/TNS-1"
-  [form]
-  (str form) ; str forces errors
-  form)
+  (:require #?(:clj [clojure.tools.reader :as reader]
+               :cljs [cljs.tools.reader :as reader])
+            [clojure.set :as set]))
 
 (defn comment?
   "Returns true if form is a (comment ...)"
@@ -40,21 +25,23 @@
   (and (list? form) (= 'ns (first form))))
 
 (defn read-ns-decl
-  "Attempts to read a (ns ...) declaration from a
-  java.io.PushbackReader, and returns the unevaluated form. Returns
-  the first top-level ns form found. Returns nil if read fails or if a
-  ns declaration cannot be found. Note that read can execute code
-  (controlled by *read-eval*), and as such should be used only with
-  trusted sources."
-  [rdr]
-  {:pre [(instance? java.io.PushbackReader rdr)]}
-  (try
+  "Attempts to read a (ns ...) declaration from a reader, and returns
+  the unevaluated form. Returns the first top-level ns form found.
+  Returns nil if a ns declaration cannot be found. Note that read can
+  execute code (controlled by tools.reader/*read-eval*), and as such
+  should be used only with trusted sources. read-opts is passed
+  through to tools.reader/read, defaults to allow conditional reader
+  expressions with :clj"
+  ([rdr]
+   (read-ns-decl rdr {:read-cond :allow
+                      :features #{:clj}}))
+  ([rdr read-opts]
    (loop []
-     (let [form (force-errors (read-clj rdr))]
-       (if (ns-decl? form)
-         form
-         (recur))))
-   (catch Exception e nil)))
+     (let [form (reader/read (assoc read-opts :eof ::eof) rdr)]
+       (cond
+         (ns-decl? form) form
+         (= ::eof form) nil
+         :else (recur))))))
 
 ;;; Parsing dependencies
 
@@ -91,12 +78,25 @@
 	(keyword? form)  ; Some people write (:require ... :reload-all)
           nil
 	:else
-          (throw (IllegalArgumentException.
-                  (pr-str "Unparsable namespace form:" form)))))
+          (throw (ex-info "Unparsable namespace form"
+                          {:reason ::unparsable-ns-form
+                           :form form}))))
+
+(def ^:private ns-clause-head-names
+  "Set of symbol/keyword names which can appear as the head of a
+  clause in the ns form."
+  #{"use" "require" "use-macros" "require-macros"})
+
+(def ^:private ns-clause-heads
+  "Set of all symbols and keywords which can appear at the head of a
+  dependency clause in the ns form."
+  (set (mapcat (fn [name] (list (keyword name)
+                                (symbol name)))
+               ns-clause-head-names)))
 
 (defn- deps-from-ns-form [form]
   (when (and (sequential? form)  ; should be list but sometimes is not
-	     (contains? #{:use :require 'use 'require} (first form)))
+	     (contains? ns-clause-heads (first form)))
     (mapcat #(deps-from-libspec nil %) (rest form))))
 
 (defn deps-from-ns-decl
diff --git a/src/main/clojure/clojure/tools/namespace/track.cljc b/src/main/clojure/clojure/tools/namespace/track.cljc
