Changed eager read-all to lazy read-seq #999

Author: mitch-kyle

CHANGELOG.md

@@ -10,7 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
  * Added support for custom data readers (#924)
  * Added `*default-data-reader-fn*` (#924)
  * Added `basilisp.pprint/print-table` function (#983)
- * Added `basilisp.core/read-all` function (#986)
+ * Added `basilisp.core/read-seq` function (#986) (#999)
  * Added various compiler arguments to CLI commands (#989)
 
 ### Changed

src/basilisp/contrib/nrepl_server.lpy

@@ -134,7 +134,7 @@
               *e    *e]
       (try
         (let [result (last
-                      (for [form (read-all (io/StringIO code))]
+                      (for [form (read-seq (io/StringIO code))]
                         (basilisp.lang.compiler/compile-and-exec-form form
                                                                       ctx
                                                                       *ns*)))]

src/basilisp/core.lpy

@@ -4437,16 +4437,31 @@
   *default-data-reader-fn*
   nil)
 
-(defn- read-iterator
-  [opts x]
-  (let [read (:read opts basilisp.lang.reader/read)]
-    (read x
-          *resolver*
-          *data-readers*
-          (:eof opts)
-          (= (:eof opts) :eofthrow)
-          (:features opts)
-          (not= :preserve (:read-cond opts)))))
+(defn read-seq
+  "Create an lazy sequence that will contain each form from the
+  ``stream``\\. If no stream is specified, uses the value currently
+  bound to :lpy:var:`*in*`. It is the callers responsibility to ensure
+  that the stream resource is not closed before the sequence has been
+  realised.
+
+  Callers may bind a map of readers to :lpy:var:`*data-readers*` to customize
+  the data readers used reading this string
+
+  The stream must satisfy the interface of :external:py:class:`io.TextIOBase`\\, but
+  does not require any pushback capabilities. The default
+  ``basilisp.lang.reader.StreamReader`` can wrap any object implementing ``TextIOBase``
+  and provide pushback capabilities."
+  ([stream]
+   (read-seq {} stream))
+  ([opts stream]
+   (let [read (:read opts basilisp.lang.reader/read)]
+      (lazy-seq (read stream
+                           *resolver*
+                           *data-readers*
+                           (:eof opts)
+                           (= (:eof opts) :eofthrow)
+                           (:features opts)
+                           (not= :preserve (:read-cond opts)))))))
 
 (defn read-string
   "Read a string of Basilisp code.
@@ -4460,7 +4475,7 @@
   ([s]
    (read-string {:eof :eofthrow} s))
   ([opts s]
-   (first (read-iterator (assoc opts :read basilisp.lang.reader/read-str) s))))
+   (first (read-seq (assoc opts :read basilisp.lang.reader/read-str) s))))
 
 (defn read
   "Read the next form from the ``stream``\\. If no stream is specified, uses the value
@@ -4479,30 +4494,9 @@
   ([stream]
    (read stream true nil))
   ([opts stream]
-   (first (read-iterator opts stream)))
+   (first (read-seq opts stream)))
   ([stream eof-error? eof-value]
-   (first (read-iterator {:eof (if eof-error? :eofthrow eof-value)} stream))))
-
-(defn read-all
-   "Eagerly read all forms from the ``stream``\\. If no stream is specified, uses the
-  value currently bound to :lpy:var:`*in*`.
-
-  Callers may bind a map of readers to :lpy:var:`*data-readers*` or a default data
-  reader function to :lpy:var::`*default-data-reader-fn*` to customize the data
-  readers used reading this string
-
-  The stream must satisfy the interface of :external:py:class:`io.TextIOBase`\\, but
-  does not require any pushback capabilities. The default
-  ``basilisp.lang.reader.StreamReader`` can wrap any object implementing ``TextIOBase``
-  and provide pushback capabilities."
-  ([stream]
-   (read-all nil stream))
-  ([opts stream]
-   (let [eof (python/object)]
-     (->> (read-iterator (assoc opts :eof eof) stream)
-          seq
-          (take-while #(not (identical? % eof)))
-          doall))))
+   (first (read-seq {:eof (if eof-error? :eofthrow eof-value)} stream))))
 
 (defn eval
   "Evaluate a form (not a string) and return its result.
@@ -4535,7 +4529,7 @@
                     (python/str))
         ctx (basilisp.lang.compiler.CompilerContext. (or src "<Load Input>"))]
     (last
-     (for [form (seq (read-all reader))]
+     (for [form (read-seq {} reader)]
        (basilisp.lang.compiler/compile-and-exec-form form
                                                      ctx
                                                      *ns*)))))

tests/basilisp/test_core_fns.lpy

@@ -2335,6 +2335,19 @@
         (let [output (load "corpus/core-load-1" "corpus/core-load-2")]
           (is (= :core-load-2 output))))
 
+      (testing "load ns form before reading more"
+        (let [ns     (-> *ns* name symbol)
+              file   (str load-dir-test "/core_load_before_read.lpy")
+              sub-ns 'tests.basilisp.corpus.core-load-before-read]
+          (spit file
+                (str "(ns " sub-ns
+                     ") (defmacro a [] 1) (defmacro b [] `(a)) (b)"))
+          (try
+            (= 1 (load "corpus/core-load-before-read"))
+            (finally
+              (remove-ns sub-ns)
+              (in-ns ns)))))
+
       (finally
         (when (bio/exists? load-dir-test)
           (shutil/rmtree load-dir-test))))))