Add images.

Images are precompiled libraries. They can be created programmatically
via the `write-image` function and then loaded with `require` or
`import`. They can also be run by the command line tool - you must
specify the path to the image without the .jimage extension.

CHANGELOG.md

@@ -2,6 +2,9 @@
 All notable changes to this project will be documented in this file.
 
 ## 0.4.0 - ??
+- `write-image` function creates pre compiled images for janet. These images
+  link to the core library. They can be loaded via require.
+- Add bracketed tuples as tuple constructor.
 - Add partition function to core library.
 - Pre-compile core library into an image for faster startup.
 - Add methods to parser values that mirror the api.

src/core/core.janet

@@ -1081,6 +1081,33 @@ value, one key will be ignored."
   (if (not= i len) (array/push ret (tuple/slice ind i)))
   ret)
 
+###
+###
+### IO Helpers
+###
+###
+
+(defn slurp
+  "Read all data from a file with name path
+  and then close the file."
+  [path]
+  (def f (file/open path :r))
+  (if-not f (error (string "could not open file " path)))
+  (def contents (file/read f :all))
+  (file/close f)
+  contents)
+
+(defn spit
+  "Write contents to a file at path.
+  Can optionally append to the file."
+  [path contents mode &]
+  (default mode :w)
+  (def f (file/open path mode))
+  (if-not f (error (string "could not open file " path " with mode " mode)))
+  (file/write f contents)
+  (file/close f)
+  nil)
+
 ###
 ###
 ### Pattern Matching
@@ -1556,8 +1583,14 @@ value, one key will be ignored."
   @["./:all:.:native:"
     "./:all:/:name:.:native:"
     ":sys:/:all:.:native:"
-    ":sys:/:all:/:name:.:native:"
+    ":sys:/:all:/:name:.:native:"])
-    ":all:"])
+
+(def module/image-paths
+  "See doc for module/paths"
+  @["./:all:.jimage"
+    "./:all:.:name:.jimage"
+    ":sys:/:all:.jimage"
+    ":sys:/:all:/:name:.jimage"])
 
 (var module/*syspath*
   "The path where globally installed libraries are located.
@@ -1621,10 +1654,17 @@ value, one key will be ignored."
                                      (if exit-on-error (os/exit 1))))
                       :source modpath})
         (file/close f)
+        (table/setproto newenv nil)
         (put module/loading modpath false)
         (put module/cache modpath newenv)
         (put module/cache path newenv)
         newenv)
+      (if-let [imgpath (find fexists (module/find path module/image-paths))]
+        (do
+          # Try image
+          (def imgsource (slurp imgpath))
+          (def img (unmarshal imgsource (env-lookup *env*)))
+          img)
         (do
           # Try native module
           (def n (find fexists (module/find path module/native-paths)))
@@ -1634,10 +1674,19 @@ value, one key will be ignored."
           (native n e)
           (put module/cache n e)
           (put module/cache path e)
-        e))))
+          e)))))
 
 (put _env 'fexists nil)
 
+(defn write-image
+  "Create an image from the file at path. Writes the output
+  image to a file at out."
+  [path out]
+  (def env (require path))
+  (def img (marshal env (invert (env-lookup _env))))
+  (spit out img)
+  img)
+
 (defn import*
   "Import a module into a given environment table. This is the
   functional form of (import ...) that expects and explicit environment
@@ -1702,26 +1751,5 @@ value, one key will be ignored."
     (put symbol-set k true))
   (sort (keys symbol-set)))
 
-(defn slurp
-  "Read all data from a file with name path
-  and then close the file."
-  [path]
-  (def f (file/open path :r))
-  (if-not f (error (string "could not open file " path)))
-  (def contents (file/read f :all))
-  (file/close f)
-  contents)
-
-(defn spit
-  "Write contents to a file at path.
-  Can optionally append to the file."
-  [path contents mode &]
-  (default mode :w)
-  (def f (file/open path mode))
-  (if-not f (error (string "could not open file " path " with mode " mode)))
-  (file/write f contents)
-  (file/close f)
-  nil)
-
 # Use dynamic *env* from now on
 (put _env '_env nil)