Add the parse function.

CHANGELOG.md

@@ -2,6 +2,7 @@
 All notable changes to this project will be documented in this file.
 
 ## Unreleased - ???
+- Add the `parse` function to parse strings of source code more conveniently.
 - Add `jpm rule-tree` subcommand.
 - Add `--offline` flag to jpm to force use of the cache.
 - Allow sending pointers and C functions across threads via `thread/send`.

janet-installer.nsi

@@ -1,6 +1,7 @@
 # This file is invoked by build_win.bat
 # Relevant configuration variables are set there.
 
+SetCompressor /FINAL /SOLID lzma
 Unicode True
 
 !echo "Program Files: ${PROGRAMFILES}"

src/boot/boot.janet

@@ -2052,6 +2052,19 @@
     (res)
     (error (res :error))))
 
+(defn parse
+  "Parse a string and return the first value. For complex parsing, such as for a repl with error handling,
+  use the parser api."
+  [str]
+  (let [p (parser/new)]
+    (parser/consume p str)
+    (parser/eof p)
+    (if (parser/has-more p)
+      (parser/produce p)
+      (if (= :error (parser/status p))
+        (error (parser/error p))
+        (error "no value")))))
+
 (def make-image-dict
   "A table used in combination with marshal to marshal code (images), such that
   (make-image x) is the same as (marshal x make-image-dict)."