Add read-all function (#986)

Emerged from #979

---------

Co-authored-by: Chris Rink <[email protected]>

Author: mitch-kyle

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
  * Added the `CollReduce` and `KVReduce` protocols in `basilisp.core.protocols` and implemented `reduce` in terms of those protocols (#927)
  * Added `basilisp.pprint/print-table` function (#983)
+ * Added `basilisp.core/read-all` function (#986)
 
 ### Changed
  * Improved on the nREPL server exception messages by matching that of the REPL user friendly format (#968)

src/basilisp/contrib/nrepl_server.lpy

@@ -122,7 +122,6 @@
   [{:keys [client* code ns file _column _line] :as request} send-fn]
   (let [{:keys [*1 *2 *3 *e eval-ns]} @client*
         out-stream                    (StreamOutFn #(send-fn request {"out" %}))
-        reader                        (io/StringIO code)
         ctx                           (basilisp.lang.compiler.CompilerContext. (or file "<nREPL Input>"))
         eval-ns                       (if ns
                                         (create-ns (symbol ns))
@@ -134,13 +133,11 @@
               *3    *3
               *e    *e]
       (try
-        (let [results (for [form (seq (basilisp.lang.reader/read reader
-                                                                 *resolver*
-                                                                 *data-readers*))]
+        (let [result (last
+                      (for [form (read-all (io/StringIO code))]
                         (basilisp.lang.compiler/compile-and-exec-form form
                                                                       ctx
-                                                                      *ns*))
-              result  (last results)]
+                                                                      *ns*)))]
           (send-value request send-fn [result {:ns (str *ns*)}]))
         (catch python/Exception e
           (debug :eval-exception e)
@@ -183,9 +180,7 @@
   [resolve-ns symbol-str]
   (let [reader               (io/StringIO symbol-str)
         {:keys [form error]} (try {:form (binding [*ns* resolve-ns]
-                                           (first (seq (basilisp.lang.reader/read reader
-                                                                                  *resolver*
-                                                                                  *data-readers*))))}
+                                           (read reader))}
                                   (catch python/Exception e
                                     (debug :symbol-identify-reader-error :input symbol-str :exception e)
                                     {:error (str e)}))]

src/basilisp/core.lpy

@@ -4428,6 +4428,17 @@
   *resolver*
   basilisp.lang.runtime/resolve-alias)
 
+(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-string
   "Read a string of Basilisp code.
 
@@ -4440,17 +4451,7 @@
   ([s]
    (read-string {:eof :eofthrow} s))
   ([opts s]
-   (first (basilisp.lang.reader/read-str s
-                                         *resolver*
-                                         *data-readers*
-                                         (:eof opts)
-                                         (if (= (:eof opts) :eofthrow)
-                                           true
-                                           false)
-                                         (:features opts)
-                                         (if (= :preserve (:read-cond opts))
-                                           false
-                                           true)))))
+   (first (read-iterator (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
@@ -4468,23 +4469,29 @@
   ([stream]
    (read stream true nil))
   ([opts stream]
-   (first (basilisp.lang.reader/read stream
-                                     *resolver*
-                                     *data-readers*
-                                     (:eof opts)
-                                     (if (= (:eof opts) :eofthrow)
-                                       true
-                                       false)
-                                     (:features opts)
-                                     (if (= :preserve (:read-cond opts))
-                                       false
-                                       true))))
+   (first (read-iterator opts stream)))
   ([stream eof-error? eof-value]
-   (first (basilisp.lang.reader/read stream
-                                     *resolver*
-                                     *data-readers*
-                                     eof-value
-                                     eof-error?))))
+   (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*` 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))))
 
 (defn eval
   "Evaluate a form (not a string) and return its result.
@@ -4517,9 +4524,7 @@
                     (python/str))
         ctx (basilisp.lang.compiler.CompilerContext. (or src "<Load Input>"))]
     (last
-     (for [form (seq (basilisp.lang.reader/read reader
-                                                *resolver*
-                                                *data-readers*))]
+     (for [form (seq (read-all reader))]
        (basilisp.lang.compiler/compile-and-exec-form form
                                                      ctx
                                                      *ns*)))))